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A N N A R B O R . M l 4 8 1 0 6 18 B E D F O R D ROW, L O N D O N W C 1 R 4 E J . E N G L A N D 7921210 I U N T U N G , KASUMbHGO THE C I S f R I R l ' T l t l h A M : E TON' UMI CS OF T HE ARMYfcORM v P S F U P A L E T 1 A ON I F UNCT A ( HAW . ) MICHIGAN. MICHI GAN STATE UNIVERSITY, University Microfilms International 30 0 N, ZEEB R O A D , A N N A R B O R . M l 48106 PH.D., 1979 THE DISTRIBUTION AND BIONOMICS OF THE ARMYWORM, PSEUDALETIA UNIFUNCTA (HAW.) IN MICHIGAN By Kasumbogo Untung A DISSERTATION Submitted to Michigan State University in p a r t ia l f u l f il l m e n t of the requirements fo r the degree of DOCTOR OF PHILOSOPHY Department o f Entomology 1978 ABSTRACT THE DISTRIBUTION AND BIONOMICS OF THE ARMYWORM, PSEUDALETIA UNIPUNCTA (HAW.) IN MICHIGAN By Kasumbogo Untung The two-year study of the armyworm is an e f f o r t to understand the re la tio n s h ip between the armyworm, host plants and i t s natural enemies. This study aims to in v e s tig a te the preference o f the armyworm to host plants fo r oviposition and feeding; the e f fe c t o f parasitism on the amount of food consumed by the la rv a e ; and the d is trib u tio n o f the larvae w ith in and between fie ld s both lo c a lly and re g io n a lly . The popu­ la tio n dynamics of the armyworm and i t s parasites is b r i e f l y analyzed. The f i e l d study was done in a wheat f i e l d and an asparagus-crabgrass f i e l d in Cass County, and the food consumption and host preference studies were carried out in the laboratory. The armyworm population in Michigan is a combination o f over­ w intering and the m igrating individuals from the southern states. Moths prefer to o v ip o s it on small grains rather than on grasses, with barley and rye preferred over oats. Larval and pupal survival and development rates are also higher in small grains, however la rv a l con­ sumption were greater on corn than e ith e r barley or oats. The parasite Winthemia rufopicta reduces food consumption by 50%, and Apanteles m i l i t a r i s reduces the consumption by 84%. Kasumbogo Untung The d is tr ib u tio n pattern o f larvae in the f ie l d depends upon the a v a i l a b i l i t y and d is t r ib u t io n o f food; the existence o f places to hide against sunshine; the la rv a l density; and the population age s tru ctu re . The d is trib u tio n in the wheat f i e l d has a tendency to be uniform under high d e n s itie s , and the d is t r ib u t io n o f larvae in the asparagus f i e l d is clumped. Nearest neighbor and quadrat counts were used to analyze the d is trib u tio n data. The R elative Net Precision method is u t i l i z e d fo r finding the optimum sampling u n it. Winthemia is a major d e te rre n t o f annyworm increase during out­ break years due to it s high numerical and functional response. Apanteles is a more host s p e c ific parasite to the armyworm, i t s p a r a s it­ ism was high in 1977 while the armyworm density was low. I t seems th a t Apanteles does not e x h ib it a high response to the density changes of the armyworm. DEDICATION To Budi, Anto, Medi, Tantyo ii ACKNOWLEDGEMENTS I wish to express my sincere thanks and appreciation to my major professor, Dr. D. L. Haynes fo r his constant d ire c tio n and guidance toward the philosophy o f pest management. His friendship and encourage­ ment w ill influence most o f my career in solving a g ric u ltu ra l pest problems in my home country, Indonesia. I also owe special thanks to Dr. R. F. Ruppel, Dr. J. A. Webster, Dr. R. L. Tummala, and Dr. T. C. Edens fo r serving on my guidance committee. I am indebted to n\y home un iv e rs ity Gadjah Mada U niversity and my sponsor MUCIA-AID fo r providing me a rare opportunity to study and have tra in in g in th is outstanding Department o f Entomology. I also wish to express my appreciation to the A.D.B. in the Netherlands which was w i l l ­ ing to support me with an additional fellowship fo r my doctorate program. I have enjoyed the in te ra c tio n and aid from the marvelous students and frie n d s , E. P. Lampert, F. W. Ravi in and A. J. Sawyer. To Budi, my w ife , thank you fo r a l l the patience and understanding throughout my t r a in in g . TABLE OF CONTENTS Pape LIST OF TABLES....................................................................................................... v ii LIST OF FIGURES..................................................................................................... x INTRODUCTION........................................................................................................... 1 LITERATURE REVIEW................................................................................................. 4 L ife History and Behavior of the Armyworm................................. Armyworm in Michigan.............................................................................. Host Preference and Food Consumption............................................ Spatial D is trib u tio n o f Larvae UnderField Condition Indices of Dispersion............................................................................ Selection of Sampling U n it ............................................................... Comparisons o f the Various Indices o f Aggregation................. Armyworm-Parasite R elatio n s h ip ........................................................ Overwintering and Supercooling A b i l i t y ........................................ 4 7 11 14 18 22 23 25 30 MATERIALS AND METHODS........................................................................................ 31 Field Sampling and Parasite Observation...................................... F ie ld Research, 1976............................................................... Field Research,....1977............................................................... E ffe c t o f P a ra s itiz a tio n by Winthemia and Apantel es on the Amount o f Food Consumed........................................................... Winthemia r u f o p ic t a ................................................................... Apantel ei~ mil i t a r i s ................................................................... Bucket Experiment.................................................................................... Spatial D is trib u tio n Study................................................................. Quadrat Count Method................................................................. Individual Mapping..................................................................... Computer Analysis o f Spatial D is t r ib u tio n ................................. Optimum Sampling U n its .......................................................................... Host Preference........................................................................................ Oviposition T e s t.......................................................................... The Developmental Rates........................................................... Food Consumption Rates............................................................. iv 31 31 32 33 33 34 34 35 37 37 40 44 46 46 47 47 Page Experiments on the E ffe c t o f Temperature on the Armyworm Development.......................................................................................... Effe ct o f Temperature to O vipo sitio n............................... Late Fall Development............................................................... Refrigeration T e s t........................................................................... Supercooling T e s t............................................................................. 50 50 51 51 52 54 RESULTS AND DISCUSSION............................................................................................ Spatial D is trib u tio n o f the Armyworm in Michigan......................... Regional D is t r ib u t io n ............................................................... Within and Between F ie ld D is trib u tio n of Larvae..................... Seasonal Appearance of the Armyworm in Michigan..................... Spring Emergence............................................................................... Field Occurrence o f Armyworm Stages in 1976................. E la c k -lig h t Data In t e r p r e t a t io n .......................................... Spatial D is trib u tio n Study................................................................. Wheat, 1976.................................................................................... Wheat, 1977....................................................... Asparagus and Crabgrass, 1976-1977.................................... Nearest Neighbor A n alysis................................................................... Spatial and Temporal E ffe c t on Larval D is t r ib u tio n .................... Quadrat Count A n alysis ............................................................................... Randomized Sampling E f f e c t ................................................................. Relative Cost Estimates........................................................................ Optimum Sampling A n alysis................................................................... Standard Deviation as an Estimate o f Precision....................... Parasite I d e n t i f i c a t i o n ........................................................................ Parasite - Host Development.................................................................... Winthemia ru fo p ic ta ( B i g ) ........................................................... Host Size Preference.......................................... Eggs and Maggot S u rv iv a l................................................. Development o f Prepupae and Pupae.............................. E ffe c t o f W. ru fo p ic ta Parasitism on Host Food Consumption............................................................... Apantel es m i l i t a r i s Walsh........................................................... Development o f Pupae......................................................... Effects o f A. m i l i t a r i s on Host Food Consump­ t i o n .......................................................................... E ffe c t o f Apantel es on Host Growth....................... Field Parasitism Rates........................................................................... 1976 Field Study......................................................................... 1977 Field Study.......................................................................... Bucket Experiment........................................................................... Oviposition Pattern o f Winthemia............................................. Host Preference......................................................................................... Oviposition Rates............................................................................ The Developmental Rates................................................................ Food Consumption Rates.................................................................. v 54 54 59 64 64 66 69 72 72 74 74 82 83 87 87 87 90 96 96 101 101 101 101 104 104 109 109 110 114 116 116 118 121 123 130 130 132 137 Page Developmental and Survival Rates.................................................... Armyworm.......................................................................................... Winthemia rufopicta ( B i g ) ....................................................... Apantel es m ilita rT s Walsh....................................................... E ffe c t o f Temperatures on S u rv iv a l.................................... Late Fa ll Development............................................................... Supercooling Test........................................................................ Frost M o r t a lit y ............................................................................ 139 139 149 153 158 162 162 169 CONCLUSIONS............................................................................................................. 171 LITERATURE CITED................................................................................................... 175 APPENDICES A. Program L isting of Nearest Neighbor Analysis.................... 179 B. Program Listing of Quadrat Count Analysis........................... 182 C. D is trib u tio n Data of Larvae in an Asparaous-Crabgrass Field in 1976 and 1977.................................... ~............................. 186 D. Degree-day Accumulations f o r Cass, Bay and Lenawee Counties from April 1 , 1976 to September 30, 1976........... 218 E. Results o f the Nearest Neiohbor Analysis of 1976 and 1977 Data................................. ~................................................ 222 F. D is trib u tio n S ta tis tic s o f Fields 111-3 and 333 -2 .......... 226 G. Calculations o f R elative Net Precision fo r 1976 D a t a ... 233 H. Food Consumption Rates o f Individual Larva Fed With Barley, Downy Wheat, and Corn Leaves...................................... 238 vi LIST OF TABLES TABLE 1. Page History o f Armyworm Damage in Michigan.......................................... 8 2. E ffe c t o f D iffe re n t Grasses on the Development o f the Oriental Armyworm. Leucanisseparata (Tahaka e t al . , 1970) 13 3. L is t o f Recorded Insect Parasites o f the Armyworm (Guppy, 1 967).............................................................................................................. 26 4 . Description of Four Oviposition Tests of the Armyworm at CLB Greenhouse........................................................................................... 48 5. Total of Armyworm Larvae in Five Sample Regions of the Wheat Field (Cass County, 1976)................... '............................... 63 6. Armyworm Density in Wheat Fields in Cassand Ingham Counties (June 1976).............................................................................. 65 7. Degree-days Requirement f o r the Development o f Armyworm Instars (Base = 4 6 ° F ) ............................................................................ 68 8 . D is trib u tio n of Armyworm Larvae in Quadrat Units of a Wheat Field (Cass County, 1976).................................................... 73 9. Relationship Between Mean and Variance o f Larval Density in a One Square Foot Sample o f Wheat Fields in Cass and Ingham Counties, 1976............................................................................ 75 10. E ffe c t o f N to the Values o f R o f Selected F ie ld s ................. 84 11. Nearest Neighbor Analysis of Asparagus Field Data (Cass County, 1976 and 1977)......................................................................... 85 12. R Values o f D iffe re n t Dates of Observation and F ie ld s / Plots of Armyworm Larvae in CassCounty, 1976........................... 86 13. C o e ffic ie n t of Variations o f D is trib u tio n S ta t is t ic s of Armyworm Larvae in Asparagus Fields (Cass County, 1 9 7 6 ) . . . 88 14. R elative Cost Estimates o f Asparagus Field (1 9 7 7 )................ 89 15. RNP Ratings of Field D is trib u tio n o f Armyworm Larvae in Asparagus (1 9 7 6 )....................................................................................... 91 v ii TABLE Page 16. RNP Ratings o f Field D is trib u tio n of Armyworm in Asparagus (1 9 7 7 )...................................................................................... 92 17. L is t o f Parasites o f the Armyworm in Michigan (Reared from Field Collections in 1976-1977)....................................................... 100 18. Number of Eggs Laid by W. rufopicta onLate Instars of Armyworm Larvae, Under Natural Conditions (1976 and 1977). 102 19. Average Time of Development of Prepupae and Pupae of W. ru fo p icta in 70°F.............................................................................. 105 20. Average Total Food Consumption of Unparasitized and P arasitized 6th Armyworm Larvae by Winthemia (cm2 of Barley Leaf A re a ).................................................................................... 107 21. Total Food Consumption of Parasitized Larvae by Apanteles m i l i t a r i s ..................................................................................................... Ill 22. Average D aily Food Consumption of Unparasitized Armyworm Larvae Parasitized by Apanteles m il i t a r i s (in cm2 barley l e a f a r e a ) ........................................................................................................ 112 23. Nearest Neighbor Index o f Armyworm Larval Groups in Crabgrass Field (Cass County, July 29, 1 977)................................. 129 24. Nearest Neighbor Index of Armyworm Larval Instars in Crabgrass Field (Cass County, July 29, 1977.............................. 130a 25. Number o f Armyworm_Eggs Laid on Three Host Plants in a Free Choice Test (x hh S . E . ) .................................................................... 131 26. Number o f Armyworm Eggs_Laid on Small Grains and Grasses in a Free Choice Test (x + S . E . ) .......................................................... 133 27. Average Longevity o f Armyworm Laevar Fed Small Grains and Grasses (x + S .E .) ....................................................................................... 134 28. Pupal Longevity from Armyworm Fed Small Grains and Grasses ( x + S . E . ) ........................................................................................................ 135 29. Average Weight and M o r ta lity o f Larvae and Pupae of Army­ worm Raised on D iffe re n t Small Grains and Grasses (x + S . E . ) ........................................................................................................ 136 30. Average Total Food Consumption of One Armyworm Larva, Reared on Three P la n ts ............................................................................... 138 31. Average Total Food Consumption of Armyworm Larvae........................ 140 32. Average D aily Rate o f Larval FoodConsumption of Armyworm. v iii 141 TABLE Page 33. Duration (days) of the Immature Stages of the Armyworm at Constant Temperatures (Guppy, 1969).............................................. 143 34. Comparison o f Regression and Standard Error Method fo r Developmental Zero of Armyworm Immature Instars (Guppy, 1 9 6 9 )................................... 148 35. E ffe c t of Three Temperatures on Ovipositional Rate (x + S . E . ) ................................................................................................... 151 36. Duration o f Development of Minthernia rufopicta a t Various Constant Temperatures (Danks, 1975a)............................................ 152 37. Comparison of Regression and Standard Error Methods for Developmental Zeros of Winthemia Stages (Danks, 1 9 7 5 a ) .. . . 154 38. Survival o f Armyworm Larvae a t D iffe re n t Constant Tempera­ tures in °C (McLaughlin, 1962, Guppy, 1969) 159 39. Development o f Armyworm Larvae Before the F ir s t Frost (East Lansing, 1 9 7 7 ).............................................................................. 166 40. Number of Pupae Producing Adults A fter Being Refrigerated a t 4 0 °F ......................................................................... '.............................. 167 41. Supercooling o f Armyworm Instars Under Natural and A r t i f i c i a l Preconditioning ( ° F ) ....................................................... 168 ix LIST OF FIGURES FIGURE Page 1. Map o f armyworm in fe s ta tio n in United States in 1953 (Cooperative Economic Insect Report, 1954)............................. 10 2. The diagram o f the bucket experiment used fo r checking f i e l d parasitism o f armyworm larvae in CassCounty 1977.. 36 3. Map of f i v e regions in the wheat f i e l d in Cass County, 1976.............................................................................................................. 38 4. The flow chart o f nearest neighbor a n a ly s is .......................... 41 5. Sample space insid e 10 x 10 sq. f t . , with 1 x 1 sq. f t . as a sampling u n i t ................................................................................ 43 5A. The flow chart o f quadrat count a n a ly s is ................................ 45 6. D is trib u tio n o f armyworm outbreaks--1975................................... 55 7. D is trib u tio n o f armyworm outbreak— 1976.................................... 56 8. D is trib u tio n o f armyworm outbreak--1977.................................... 57 9. D is trib u tio n o f armyworm o u tb re a k --!978.................................... 58 10. Armyworm la rv a e d is t r ib u t io n in wheat f ie ld s (1 9 7 6 )............. 60 11. Armyworm la rv a e d is t r ib u t io n in Cass Countywheat fie ld s (1 9 7 6 ) 61 12. Armyworm la rv a e d is t r ib u t io n in Lenawee County wheat f ie l d s (1 9 7 6 )........................................................................................... 62 13. F ie ld occurrence o f armyworm stages in Southern Michigan, 1976.......................................................... ‘ ......................................... “ . . . 67 14. Number o f armyworm moths caught in the b la c k -lig h t traps in Cass and Lenawee Counties 1976...................................... 70 15. Number o f armyworm moths caught in the b la c k -lig h t trap in Bay County 1976................................................................................ 71 x Page FIGURE 16. Variance/Mean r a t i o of armyworm larvae in 1 sq. f t . sample in a wheat f i e l d ....................................................................... 76 17. D is trib u tio n o f armyworm larvae in a wheat f i e l d in Cass County, May 24, 1977.............................................................................. 77 18. D is trib u tio n o f armyworm larvae in a wheat f i e l d in Cass County, June 10, 1977............................................................................ 78 19. D is trib u tio n o f armyworm larvae and plants in an asparagus f i e l d ( f i e l d 1 1 1 - 3 ) ................................................................................ 79 20. D is trib u tio n o f armyworm larvae and plants in an asparagus f ie ld ( f i e l d 333-1 ) ................................................................................ 80 21. D is trib u tio n o f armyworm larvae and plants in an asparagus f i e l d ( f i e l d 4 4 4 - 1 ) ................................................................................ 81 22. R elative net precision la rv a l sampling ( f i e l d o f quadrat sizes fo r armyworm 111-3 the density = 5 3 ) ....................... 93 R elative net precision o f quadrat sizes fo r armyworm la rv a l sampling ( f i e l d 333-1 , the density = 1 1 0 )..................... 94 Relative net precision o f quadrat sizes fo r armyworm la rv a l sampling ( f i e l d 1 1 1 -2 , the density = 2 3 ) ...................... 95 25. Relationship between quadrat size and density estimates ( f i e l d 111-2, density = 2 2 ) ............................................................ 97 26. Relationship between quadrat size and density estimates ( f i e l d 111-3, the density = 5 3 ) ....................................................... 98 27. Relationship between quadrat size and density estimates ( f i e l d 333-1 , the density = 1 1 0 )...................................................... 99 28. Relationship between the number of Winthemia eggs la id on one armyworm la rv a and the percentage o f eggs producing a d u lts ............................................................................................................ 103 29. Daily food consumption and larvae p a ra s itiz e d o f unparasitized armyworm larvae byWinthemia............................................... 108 30. Daily food consumption o f unparasitized armyworm larvae and larvae p a ra s itize d by Apantel es m i l i t a r i s ......................... 113 23. 24. 31. I n i t i a l re la tio n s h ip between number o f Apantel es cocoons emerged from armyworm l a r v a , and to ta l food consumption of p a ra s itize d la rv a (up to day 6 a f t e r e c lo s io n )................. xi 115 FIGURE Page 32. Parasitism of armyworm larvae in wheat (Cass County, 1976)........................................................................................ 117 33. Number o f Winthemia adults caught in emergence traps (Cass County, 1 976)................................................................................ 119 34. Parasitism o f armyworm larvae in a wheat f i e l d (Cass County, 1977)............................................................................................. 120 35. Parasitism of armyworm larvae in a wheat f i e l d (bucket experiment, CassCounty, 1 9 7 7 )........................................................... 122 36. Relationship between armyworm la rv a l density with Winthemia parasitism in the wheat f i e l d (Cass County, June 19, 1 976)........................................................................................... 124 37. Relationship between armyworm la rv a l d en sity, with Winthemia parasitism in the wheat f i e l d (Cass County, June 12, 1976)........................................................................................... 125 38. D is trib u tio n o f para s itize d armyworm larvae by Winthemia and unparasitized larvae in 10 x 19 sq. f t . asparagus f i e l d (Cass County, July 29, 1 977)................................................ 126 39. Relationship between armyworm la rv a l de n s ity , with Winthemia parasitism in crabgrass-asparagus f i e l d (Cass County, July 29, 1 9 7 7 ).......................................................................... 127 40. Rate of armyworm la rv a l consumption (b a r le y , wheat and c o rn ).............................................................................................................. 142 41. The rate o f development o f six larva instars of the army­ worm at d if f e r e n t temperatures (Guppy, 1 969) 144 42. The rate o f development o f egg and pupa o f the armyworm at d if f e r e n t temperatures (Guppy, 1 9 6 9 )............................................ 145 43. Developmental rate of the s ix la rv a l instars o f the army­ worm (Guppy, 1 969)................................................................................... 147 44. Estimation of developmental zero o f immature stages o f the armyworm using standard e rr o r method (Guppy, 1 9 6 9 )................. 150 45. Developmental rate o f Winthemia ru fo p ic ta l i f e stages 155 46. Estimation o f developmental zero of Winthemia l i f e stages using the standard e rro r m ethod..................................................... 156 47. Estimation of developmental zero of Apanteles m i l i t a r i s larvae (Calkins and S u tte r, 1 976)................................................... 157 xii FIGURE Page 48. Survival of armyworm larvae as a function of temperature in °C (McLaughlin, 1962 and Guppy, 1969).................................... 160 49. Survival o f eqgs and pupae as a function o f temperature in °C...............* ............................................................................................ 161 50. Instantaneous survival ra te o f eggs and pupae of the armyworm....................................................................................................... 163 51. Instantaneous survival ra te o f 1 s t, 2nd, and 3rd instars o f armyworm la r v a e ................................................................................ 164 52. Instantaneous survival ra te of 4 th , 5th and 6th instars of armyworm la r v a e .................................................................................. x ii i 165 INTRODUCTION The armyworm, Pseudaletia unipuncta (Haw.) (Lepidoptera:Noctuidae) has been recognized as a po ten tial pest of corn and small grains in Michigan. The significance o f the arniyworm to Michigan's a g ric u ltu re has increased in the past 5 years, due to the unusual consecutive out­ breaks which occurred in 1975, 1976, and 1978. The e f fe c tiv e measures developed by entomologists consist prim ari­ ly o f pesticide treatment o f infested f ie ld s (Ruppel, 1973). The lack o f the biological information about the arniyworm and i t s environment contributes to the practice o f "insurance spray" type o f co n tro l. Due to the suddenness of armyworm outbreaks, most o f the control treatments are applied improperly, which makes the pesticide applications increase the cost o f control monetarily and environmentally. Understanding the complex and dynamic re la tio n s h ip between the armyworm, host plants and i t s natural enemies is the, prereq uisite for a b e tte r armyworm management program. Biological information and environ­ mental data are the most important parameters fo r developing various management strateg ies under the s tru ctu re o f o n -lin e pest management (Haynes e t a l . , 1973). Within the context o f the pest management framework, th is research is an introductory contribution to the bio log ical research component. Due to the preliminary c h a ra c te ris tic s o f th is report covers a broad subjects o f d is trib u tio n and bionomics o f the armyworm. Techniques and 2 a n a ly tic a l methods have been developed during the conduct o f this research p ro je c t. The i n i t i a l population source is an important element fo r the complete understanding o f the armyworm ecosystem. An armyworm popula­ tio n in Michigan can re s u lt from a overwintering la rv a l population and/or from a migrating adult population. There is no published information about the overwintering phenomenon o f arniyworm in Michigan. By using emergence tra p s , l i g h t traps and f i e l d observations, the seasonal occurrence o f the armyworm in Michigan can be analyzed. In th is study, observations of la te f a l l development o f armyworm larvae and pupae, and t h e ir supercooling points were made to provide some in s ig h t into the overwintering phenomena. During the outbreak years i t is necessary to understand the d i s t r i ­ bution between f ie ld s both lo c a lly and r e g io n a lly , to estimate the regional density of the arniyworm. This information can be obtained by checking the density of the armyworm population throughout the state by using an appropriate sampling method organized into systematic survey. The sampling methods should be derived from the c h a ra c te ristic s of the s p a tia l d is trib u tio n o f the armyworm w ith in the f i e l d . The o p t i ­ mum sampling u n it is the u n it which gives the highest accuracy f o r a given cost. Since the s p a tia l d is t r ib u t io n o f the larvae w il l be d i f f e r ­ ent from one f i e l d to another, two types o f f ie ld s were used to analyze w ith in f i e l d d is t r ib u t io n ; a wheat f i e l d and an asparagus-crabgrass fie ld . For speeding up the process o f determining the optimum sampline u n it from a given d is tr ib u tio n data, th is study is try in g to demonstrate 3 the use o f a computer programming. Computer programs have been developed to c a lc u la te various indices o f armyworm dispersion and other d is t r i b u ­ tio n s t a t i s t i c s . This step enables the user to c a lc u la te the optimum sampling u n it " o n -lin e " , fo r wide ranges o f density and d is t r ib u t io n . During the high population year (1976) and the low population year (1 97 7 ), the in te ra c tio n between the armyworm and i t s p a ra s ite s , Winthemia rufopicta ( B ig ) , Apanteles m i l i t a r i s , and Meteorus communis have been b r i e f l y examined. Due to the moving behavior of the pest, the population dynamic study could be done only to the f i r s t generation of larvae. Crop loss estimates due to the armyworm feeding required informa­ tio n about to ta l food consumption o f la rv a l in s ta rs . Damage.or crop losses depends upon many factors such as la rv a l d e n s ity , la rv a l-a g e d i s t r ib u t io n , host plant condition and parasitism ra te s . The higher the percentage of parasitism the lower the damage caused by feeding larvae. This in te ra c tio n was studied fo r Winthemia and Apanteles parasites. Even though armyworm is known as a polyphagous species, f i e l d evidence was found to show th a t th is pest has a host preference. Host preference studies were conducted which demonstrate preference to d if f e r e n t plants fo r feeding and oviposition s i t e . This information was used p a r t i a l l y to explain the movement habit o f the larvae in the f i e l d . Based on the a v a ilab le references (Guppy, 1969; Danks, 1975b; Calkins and S u tte r, 1976) and various experiments in the controlled growth chamber, the e ffe c t o f temperature to the development and survival o f the armyworm and i t s parasites is discussed. This information is essential fo r the development o f population dynamics model. LITERATURE REVIEW L ife History and Behavior of the Armyworm Most o f the l i t e r a t u r e on the arniyworm deals with the l i f e history esp e c ia lly during the outbreak years. These papers range from R iley (1883), Davis and S a tte rtw a it (1916), Breeland (1 9 5 8 ), Pond (1 9 6 0 ), to the most recent studies by Guppy (1961 in Ontario, Canada. The armyworm overwinters mainly as p a r t i a l l y grown larvae ( th ir d to sixth in s ta r ) in the soil beneath thick mats o f grassy vegetation. The species is able to add extra instars during overw intering, th a t depend on the length and temperature of the w in te r, and the in s ta r in which overwintering began (Breeland, 1958), Guppy (1961) says th a t the armyworm does not overwinter in eastern Ontario, he suggests th a t moths in Ontario come from the overwintering stages in the more southernly regions. In Michigan the f i r s t spring adults usually appear in the black l i g h t tra p in the e a rly spring, range from 100-200° DD (D > 4 6 °F ). If the physiological time analysis is applied to the development of the stages o f the armyworm, th is early spring emergence indicates th a t some of the insects might overwinter as adults or as pupae, or th a t there is spring f l i g h t northward from the southern part o f the range o f the insect. 4 5 The female moths emerge s lig h t ly e a r l i e r than the males. Moths are n o ctu rn al, during the day they are ra re ly seen in the f i e l d . Mating u su ally occurs one to three days a f t e r adult emergence, appar­ e n tly only one mating is required to f e r t i l i z e the e n tir e l i f e produc­ tio n o f female eggs. F i r s t oviposition occurs 6 days a f t e r adult emergence, and female moths continue depositing eggs fo r about a week. Eggs are la id in masses, and are composed of several rows of eggs covered with a white adhesive f lu id fastening them together. Moths p re fe r to lay eggs in dry m aterials such as straw of haystacks, corn stubb le, and dry leaves. In small grain f ie ld s eggs are la id on dry leaves on the base of plants and on the t i p of young leaves. O viposition normally begins a f t e r dark. The fecundity o f armyworm moth is high, one moth has a potential to la y up to 2000 eggs, however, the number of eggs deposited by a single female can vary g re a tly . The lif e t im e egg production of the moth varies from a low o f 5 to a high a t 1759 and an average o f 454 eggs (Breeland, 1958). A fte r deposition of a ll eggs, there is usually a post ovip o s itio n period o f a few days before death of the moth occurs. The l i f e o f a moth can be up to 27 days with an average o f 10 days. Moth oviposits most frequently in t ig h t places as provided by the narrow space between sheath and blade o f growing grasses or the same in c u t, dried straw or corn s ta lk s . Riley (1883) stated th a t e a rly in the season the moths oviposited by preference in the cut straw of haystacks. Eggs are la id in masses, the moth seldom deposits a l l o f her eggs in one mass, but may deposit a l l of her eggs in a given oviposition 6 period. Average incubation period in the middle o f the summer is 6.4 days (Breeland, 195 ) . There are normally six instars o f larvae in which the develop­ mental rates are dependent upon the temperature. Guppy (1969) has investigated the e f f e c t o f temperature on the development of immature stages o f the armyworm. All stages o f larvae feed on leaves with a d i f f e r e n t consumption ra te s . Most of feeding damage is done by la te instars o f la rv a e . The f i r s t and second in s t a r are very d i f f i c u l t to detect in the f i e l d because o f t h e i r small size (3 -6 mm. of length) and the hab it of drop­ ping on silken threads when disturbed. A fte r dropping, the larvae remain motionless in a C-shape position f o r some time. sixth in s ta r have common habits. The t h ir d to Larvae are active at dusk and dawn and do most o f t h e i r feeding a t n ig h t, during the day they remain con­ cealed under f o l ia g e , ground d e b ris , or in the crown of small grains. When disturbed la rv a e w i l l assume a motionless C-shaped po sitio n . The larvae concentrate feeding on the a v a ila b le green leaves, and i f most of the green leaves are chewed, they s t a r t clipping heads. I f the a v a i l ­ able food in one f i e l d cannot support t h e i r numbers, larvae w i l l s t a r t marching and m igrating to adjacent f i e l d s . F i r s t generation larvae feeding in small grains and corn, have e ith e r developed in the f i e l d or migrated from adjacent grassy f i e l d s . Pupation normally occurs in the s o il to a depth of one inch or less depending upon the te x tu re o f the s o i l . In small grains f ie ld s pupation occurs in the soil under or around the base o f the p la n t. 7 There are three generations o f armyworms each year in Michigan. The f i r s t generation larvae are the most destructive to small grain crop. The second generation larvae ra re ly causes any economic damage, since they concentrate in forage crops, pastures and grassy f ie l d s . The t h ir d generation larvae also causes no economic damage. Armyworm in Michigan Records of armyworm outbreaks in Michigan since 1951 can be found in the Cooperative Economic Insect Report of USDA. Research before 1951 can be obtained from the Insect Pest Survey B u lle tin and Losses of USDA, and A g ric u ltu ra l Crop Report o f Michigan Secretary of State. Armyworm and other pest records in Michigan have also been reported in Pest A le rt (previously a Weekly Pest Report). This publication has been c irc u la te d by the Department of Entomology, Michigan State Univer­ s i t y , since 1963. According to the a v a ila b le records, armyworm before 1960 was a minor or unimportant pest of small grains in Michigan. armyworm was scattered and lo c a liz e d . The damage by In 1938 and 1954, armyworm in fe s ta tio n s were confined mostly to localized areas of the middle and upper counties o f Michigan. Monroe County was the only county in the southern part of the state which reported an armyworm in fe s ta tio n . Table 1 is the summarized record of armyworm outbreak in Michigan since 1900 with a l i s t o f counties where outbreaks were reported. Unfortunate­ l y , the information about acreage density and control treatment are lacking. A f te r 1960 i t appears th a t the armyworm became a more 8 Table 1. Year History o f Arniyworm Damage in Michigan Counties Where the Damage was Reported 1938 G r a t io t , Montcalm 1952 Lapeer, Charlevoix, Oceana, Monroe 1953 Local outbreak, location is not reported 1954 Bay, G r a tio t, Saginaw, Mackinaw, Cheboygan, A lg e r, Chippewa 1957 From Ottawa to Bay Co., included Ingham and Osceola 1964 Monroe, Livingston, Berrien, A llegan , Van Buren, Cass, Kalamazoo, Wayne 1965 St. Joseph, Van Buren, Berrien Allegan, Ottawa, Macomb 1975 All southwestern counties from Berrien Co. up to Tuscola Co. 1976 B e rrie n , St. Joseph, Cass, Van Buren, Kalamazoo, Allegan, Lenawee, Monroe, Tuscola, Bay, Saginaw Note 100 acres are treated. The worst in US h is ­ tory . 2300 acres were treated 9 important pest and in fe s ta tio n areas extend in to southwestern and westcentral counties. However, fewer reports came from northern and upper peninsula counties. Control measures included applications of Toxaphene, 1953; and Sevin, Malathion, Parathion, Dylox or Diazinon in 1975 and 1976. The d i f f i c u l t i e s in applying pesticides fo r armyworm control are related to proper tim ing. Many f ie ld s were treated needlessly because treatments were e ith e r applied under l i g h t in fe s ta tio n or delayed u n til la rv a l feeding was completed. Natural enemies such as Tachinid f l y , Winthemia quadripustulata and Braconid parasite (not mentioned by species but most l i k e l y Apanteles m i l i t a r i s ) , and diseases (fungus and v iru s ) were considered as the main fa c to r to control the population a f t e r the outbreak. Compared with other states such as Tennessee, M issouri, Kentucky, Wisconsin, I l l i n o i s , e t c . , Michigan has less o f a problem with armyworm damage. I t appears th a t Michigan missed the worst outbreak of armyworm in the history of the United States and Canada, in 1953. While other states suffered hundreds o f thousands of do llars damage to small grain and corn f ie ld s by the armyworm, Michigan experienced only 100 acres o f l i g h t in f e s ta tio n . This s itu a tio n can be seen in Figure 1 which is the map of the in fe s ta tio n area in 1953. Even though the in te rv a l o f an "armyworm year" in one location is not regular and cannot be predicted, i t is in te re s tin g to note th a t a f t e r the f i r s t year o f outbreak there w i l l usually follow one or two more outbreaks less severe than the f i r s t . In Michigan, fo r example, the outbreak in 1964 was followed by 1965 outbreak, 1975 followed by 10 Fipure 1 . Map o f armyworm in fe s ta tio n in the United States in 1953. ★ C o o p e ra tiv e Economic Insect Report Published by USDA. 11 1976 outbreak. In other states the 1953 outbreak was followed by out­ breaks in 1954 and 1955. Host Preference and Food Consumption The armyworm is a polyphagous insect, feeding on a great v a rie ty o f plants. The larvae have been reported to feed on small g ra in , corn, sorghum, grasses, beans, forage crops, vegetable crops and a few f r u i t crops. I t is generally accepted th a t the armyworm prefers grasses over other groups o f plants. However there should be a c e rta in subset of the grass fa m ily which the armyworm prefers most. Guppy (1961) reported th a t during the 1954 outbreak in Eastern Ontario most of the population was in oat f i e l d , but he suggested th a t i t is u n lik e ly t h a t oats are the most preferred host. Crop m aturity and stand density o f stubble and dead leaves fo r ovip o s itio n sites may be more important in a ttra c tin g the insect than host species. Breeland (1958) made an oviposition te s t using 6 small grains and grasses. Wheat received highest egg deposition, then Dali is grass ( Paspalum d ila ta tu m ) ; Johnson Grass ( Sorghum halepence) ; and barley ( Hordeum vulgare) . The lowest eggs were deposited in oats ( Avena s a tiv a ) ; Sudan Grass ( Sorghum vulgare) . There is no report about the e f f e c t of d i f f e r ­ ent hosts to the development of larvae and pupae o f the armyworm. For the comparison works of Tanaka et a l . (1970) can be used as a reference. Tanaka e t a l . (1970) working with the o rie n ta l armyworm ( Leucania separata) did host preference investigations in the laboratory using seven d i f f e r e n t grasses. They checked the e f fe c t o f hosts on m o r ta lity 12 of larva and pupae, pupal weight, number o f in s ta r of la rv a e ; Table 2 summarizes some o f t h e i r observations. From this ta b le i t can be con­ cluded th a t the armyworm cannot survive in c ertain grass such as Napier Grass, and suffered a high m o rta lity in Bahia Grass and Rhodes Grass. Extra instars which developed w hile feeding on c e rta in p la n ts , demon­ s tra te th a t the larvae are under stress. Information about host preference of armyworm is important fo r understanding the migrational behavior of the pest in a f i e l d . The potential food consumption by a single larva is high, which allows armyworm population to ra p id ly exceed an economic threshold. David and S a tte rth w a it (1916) state th a t with 8,890 corn plants per acre, i t would require 21,473 larvae to destroy an acre o f corn two f e e t high. This number represents the potential progeny o f only 40 moths. Most food is consumed by the l a t e r in s ta rs . Tanaka and Wakikado (1974) reported th a t the f i r s t to fourth instars consumes 3.5% o f the to ta l food needed fo r la rv a l development, the f i f t h in s ta r consumes 12.8%, and the sixth in s ta r consumes 84.7%. Ninety-seven percent of the to ta l food consumed was done by the f i f t h and sixth in s ta rs . Mukerji and Guppy (1970) investigate the q u a n tita tiv e re la tio n s h ip between food consumption and the growth of the armyworm. When the armyworm feeds at a high r a t e , i t is able to accelerate development, increase growth, and maintain a high reproductive p o t e n t ia l. When the ra te of food intake is low; development, growth, and fecundity are reduced. 13 Table 2. E ffe c t of D if fe r e n t Grasses on the Development of the Oriental Arrnyworm. Leucania separata (Tahaka e t al . , 1970) M o r ta lity o f Larva Number o f In s ta r Larva Pupal Weight (mg) 5.8 6 385.0 2. Corn (Zae mays) 24.0 6 382.2 3. Sorghum (Sorghum vulgare) 17.0 7 384.9 4. Dali is Grass (Paspalum d ilatatum ) 16.7 7 357.3 5. Rhodes Grass (Chloris gayana) 47.6 9 272.2 6. Bahia Grass (Paspalum notatum) 90.9 7 340.7 Host Plant 1. Fescue (Festuca arundinaeca) 7. Napier Grass (Pennisetum purpureum) 100.0 - -0- 14 S p a tia l D is trib u tio n o f Larvae Under Field Condition Spatial d i s t r i b u t i o n of a population in a natural h a b ita t, is important in the study o f the ecology o f c ertain animals. Even though the s p a tia l d i s t r i b u t i o n does not t e l l much about the behavior and dynamics o f population, i t can be used fo r measuring population size and describing the condition of the population. The dispersion pattern o f a population, a t any in s ta n t represents the culmination of a history of b i r t h , death and movement. Ey observing the dispersal pattern of the ind ividu als some in s ig h t in to the biological c h a ra c te ris tic s of the species, and the reasons behind the changes in the density o f the popu­ la tio n can be gained. Indices o f the dispersion are needed to c le a r ly describe the spatial pattern or to use in te s tin g the departure from randomness for sampling purposes. Many dispersion indices which have been developed, b a s ic a lly can be divided into two categories based on the sampling scheme, p lo t (quadrat) counts and distance measurements. The choice of whether to use p lo t counts or distance measurements might be dictated by physical conditions which are not under control of the researcher. Observed f i e l d counts, re s u ltin g from a chosen sampling method, must be compared to a th e o re tic a l series of p ro b a b ility d is t r ib u t io n , to fin d out which d i s t r i b u t io n is the most f i t to represent the s patial c h a ra c te ris tic s o f the population. A favorable agreement between the observed data and the calculated values o f th e o re tic a l series should be made c a r e f u l l y , otherwise i t may lead to an unwarranted conclusion. 15 VJaters and Henson (1959) l is t e d three p o s s ib ilit ie s th a t can r e s u lt in mi s in t e r p r e t a tio n : 1. The observed data might s a t i s f a c t o r i l y f i t more than one d is t r ib u t io n . 2. Some d is trib u tio n s can a ris e from several d is t in c t mathematical and b io log ical models. 3. The parameters of most dis c re te frequency d is trib u tio n s are strongly influenced by the form and size of sampling u n it , and by population density. There are three th e o re tic a l d is trib u tio n s which are used to describe the basic types of s p a tia l dispersion of population: 1) random d is t r ib u t io n ; 2) regular d is tr ib u tio n ; and 3) contagious d is t r ib u t io n . 1) Random d is t r ib u t io n or Poisson d i s t r i b u t i o n . The frequency d is trib u tio n is a Poisson d is tr ib u tio n given by the function ax e " a Px = S r where, Px = the p r o b a b ility o f x individual in asampling x = number o f ind iv id u a ls per un it a = mean number o f in d ividu als per un it e = base o f natural logarithm = 2.71828 unit The assumptions th a t should be met by th is d is tr ib u tio n are: a. Each individual has the same chance of f a l l i n g into any u n it. b. Each u n it has the same chance o f being f i l l e d by any in d iv id u a l. 16 c. The presence of one individual in a u n it does not in any way a ffe c t the chances of another f a l l i n g into i t . d. The samples must be small r e l a t i v e to the population. These conditions are less l i k e l y to happen in the f i e l d . As E l l i o t (1977) pointed ou t, the agreement with Poisson series simply means th a t the hypothesis o f randomness is not disproved o r , in another word, non-randomness is present but cannot be detected by sampling techniques in the f i e l d . I f the size of the sampling un it is much la rg e r or much smaller than the average size o f clumps of in d iv id u a ls , and these clumps are re g u la rly or randomly d is t r ib u t e d , then the dispersion of the population is apparently random, and non-randomness is not detected. The tendency to randomness often increase with the age of a population which could be due to the decrease in population density or to the divisio n of larg er clumps in to several smaller clumps. 2) Regular or Uniform D is t r ib u t io n . The mathematical model for the regular d is tr ib u tio n is a p o sitive binomial which is given by the function: „ P(x) where, P " k! x !(k -x )! qpX = the p r o b a b ility o f x in d ividu als in a sampling u n it p = p ro b a b ility o f any point in the sampling unit being occupied by an individual q = (1 - P) k = the maximum possible number o f individuals a sampling u n it could contain. 17 The dispersion of a population is regular when the individuals in the population are r e l a t i v e l y crowded and move away from each other. Under these conditions, the number of individuals per sampling unit approaches the maximum possible, the variance o f the population is less than the mean. T e r r i t o r i a l behaviour w i l l often produce a uniform spacing of the in d iv id u a ls . Therefore, a regular d is trib u tio n ra re ly describe the dispersion o f population over a large area, but sometimes describe the a small area. dispersion in 3) Contagious or Aggregated D is t r ib u tio n . The mathematical model for the contagious d is t r ib u t io n is a negative binomial which is given by the fun ction , where, PA n _ n + u l~ k ( k+x-1)! P( x ) " x Y ( k - iy i , u nX = the p r o b a b ility of xin d ividu als in a sampling u n it u =a rithm etic mean The parameters of th is d is t r ib u t io n are u and the exponent k, they are estimated from the frequency d is tr ib u tio n of the sample by the s t a t i s __ tics A x and k. There are several methods of c a lc u la tin g k value (Anscombe, 1949, 1950). The spatial d is tr ib u tio n o f a population is contagious when the variance is s ig n if ic a n t ly g re a te r than the mean. There are always d e fin ite clumps or patches o f in d iv id u a ls in th is d is t r ib u t io n . The individuals tend towards aggregation due to environmental factors or behavior o f the animal. The dispersion pattern depends upon the size of the clumps, the distance between clumps, and the s patial d is trib u tio n 18 o f in d ividu als w ith in each clump. D iffe r e n t species w i l l usually show d i f f e r e n t contagious d is trib u tio n s w ith in the same h a b ita t, and the dispersion pattern o f one species may vary w ithin the same h a b ita t. Bliss and Calhoun (1954) explained th a t the negative binomial d is tr ib u tio n can a ris e in the population in fiv e d if f e r e n t ways, i . e . , 1) heterogeneity in the p r o b a b ility of occurrence: 2) true contagion; 3) compounding Poisson and logarithm ic d is trib u tio n s ; 4) birth -d e a th immigration process; and 5) inverse binomial sampling. In addition to these, the sampling method chosen by the experi­ menter may e f f e c t the apparent d is t r ib u t io n , contagious d is trib u tio n (o r other d is tr ib u tio n s ) involve both b io lo g ic a lly s ig n ific a n t and s t r i c t l y a r t i f i c i a l components. Indices o f Dispersion Many d if f e r e n t indices have been developed to compare d i f f e r e n t patterns of dispersion in populations. E l l i o t (1977) emphasized th a t the ideal index o f dispersion should possess the follow ing a ttr ib u te s : 1. I t should provide real and continuous values over the range of maximum r e g u la r it y , through randomness, to maximum con­ tagion. 2. I t should not be influenced by v a ria tio n in the size o f the sampling u n it (quadrat s i z e ) , the number o f sampling units ( n ) , the sample mean ( x ) , and the to ta l numbers in the sample ( I x ) . 19 3. I t should be easy to c alculate from large amounts of d a ta . 4. I t should enable differences between samples to be tested for s ig n ific a n ce . There is no p erfect index o f dispersion which f u l f i l l s a l l those conditions, some assumptions are made as a constraint o f the indices. The follow ing indices are most fre q u e n tly used. 1. Variance to Mean Ratio - This te s t is based on the e q u a lity of variance and mean in a Poisson s e rie s , and the in e q u a lity of both para­ meters in the regular and contagious d is t r ib u t io n . The variance to mean r a t i o , or index o f dispersion ( I ) is calculated by the following formula, I = = x if, S (x -x)2 x (n -l) I > 1, contagious d is tr ib u tio n is suspected, I = 1 a random d i s t r i ­ bution and I < 1 a continuous d is tr ib u tio n is suspected. Because th is index is strongly influenced by the number of in d i­ viduals in the sample, i t is a good s t a t i s t i c a l t e s t fo r an agreement with the Poisson d is t r ib u t io n , but i t is not a good measure of the degree o f clumping in a population. 2. k in the negative binomial - I f the negative binomial can be f i t t e d to the d a ta , the value o f k gives a measure of dispersion. The smaller the value of k, the g re a te r the extent of aggregation; whereas, a la rg e value (over about 8) indicates th a t the d is tr ib u tio n is approaching a Poisson. 20 The disadvantages o f th is index are: 1) i t is not independent of the number o f sampling u n its ; 2) i t goes to + i n f i n i t y a t randomness; and 3) the values o f k is often influenced by the size o f the sampling u n it. Comparisons o f the level of clumping can only be made with k, when n and the u n it size are the same in each sample. The s t a t i s t i c k has been used in measuring the degree of popula­ tio n aggregation f o r various h a b ita ts , and developmental stages (Waters, 1959; Harcourt, 1961, 1963, 1965). 3. M o ris ita Index of Dispersion - Mori s ita (1959, 1962, 1964) has developed the follow in g index of dispersion, Tx 10 - n Z [x (x -in " n Ex(Ex-l) _ nZ(x2) - Zx ‘ ( £ x ) ‘ - Zx This index has the advantage t h a t , i t is independent of the sample mean, t o t a l numbers in the sample, and type of d is t r ib u t io n , but i t is affected by the number o f sampling un it ( n ) . Therefore, i t is a good comparative index o f dispersion, when each sample contains the same number of sampling u n its . When the d is tr ib u tio n is Poisson th is index w i l l approach u n it y , when the d is tr ib u tio n is contagious the index w i l l be g re a te r than one, and when the d is trib u tio n is regular the index w i l l be less than one. M o ris ita (1959) has investigated changes in 16 with d if f e r e n t sizes o f quadrat s iz e . From th is he could estimate the mean size of the clumps. 4. Nearest neighbour method - A ll of the above three indices with the other indices ( i . e . , Lloyd index, Deevey's, Cole's index, e t c . ) are 21 a ffe c ted to a greater or lesser extent by quadrat s iz e , and i t is often impossible to detect non-randomness when clumps o f individuals are very small. These problems can be overcome by using indices which are based on nearest neighbor measurement such as nearest neighbor method of Clark and Evans (1 9 5 4 ), and closest individual or distance method of C attain and C u rtis (1956). In th is method, the individual is selected at random, and the distance between i t and i t s nearest neighbor is measured. I f N is the number o f observations, the observed mean distance between an individual and i t s neighbor i s , r r = ^ N I f the dispersion o f ind ividu als is random, the expected or mean value of the average distance between a randomly selected individual and i t s nearest neighbor i s , E( r ) where, 2ph p = the density of the population expressed as the number o f in d iv id u a ls per u n it area. The r a t i o , R = eUT is the measurement o f the departure from randomness. d i s t r ib u t io n is aggregated. I f 1 > R > 0 the The more clumped the closer R is to zero. The population has a reg ular d is tr ib u tio n i f R is between 1 and 2.496. To t e s t the sign ifican ce o f the va lu e , C la rk andEvans deviation o f R fromexpected (1954) suggest the useo f a standardized normal 22 v a ria te , where, (r) _ .26136 (Np)Js A l im it a t io n o f the nearest neighbor analysis in a spatial study is th a t population density must be known and individuals must be statio n a ry w hile measurements are being taken. Selection o f Sampling Unit The study o f s p a tia l d is t r ib u t io n of ind ividu als is useful in selecting a sampling u n it fo r a sampling program. down six 1. Morris (1955) la id c r i t e r i a f o r selecting a sample u n it: I t must be such th a t a l l units o f the universe have an equal chance of s e le c tio n . 2. I t must have a s t a b i l i t y . 3. The proportion of the insect population using the sample u n it as a h a b ita t must remain constant. 4. The sampling un it must lend i t s e l f to conversion to un it areas. 5. The sampling u n it must be e a s ily delineated in the f i e l d . 6. The sampling should be o f such a size as to provide a reasonable balance between the variance and cost. In th is report I have emphasized the sixth c r i t e r i a . The f a m il i a r p rin c ip le o f selecting a u n it is the one th a t gives the smallest variance fo r a given cost, or the smallest cost fo r a 23 prescribed variance. From prelim inary sampling variances of each of d if f e r e n t units size (Su2) can be calculated. By c a lculatin g a common basis f o r these units i t is possible to a rr iv e at the size of the smallest u n it. Cochran (1963) used the term "Relative Net Precision" (RNP) to compare d i f f e r e n t u n it sizes. RNP where, Mu For a given fixed cost, a - - u-2CuSu2 = r e l a t i v e size o f u n it Su2 = variance among u n it t o ta ls Cu = r e l a t i v e cost o f measuring one u n it. Cu can be calculated as a r a t io of u n it size over a number of square foot th a t could be sampled with a fixed resources (fixed resource = sampling tim e ). For example th is value shall include the amount of resource (tim e) spent fo r processing one sample, and resources (time) spent to tra v e l between samples. For a fixed cost, a samole u n it with the high RNP gives more pre­ cision than one with lower RNP. The comparison between RNP of d if f e r e n t u n it sizes can be used to in d ic a te the optimum sample u n it fo r a certain d is trib u tio n type. Comparisons o f the Various Indices o f Aggregation For a given species, i t is important to know whether d if f e r e n t populations have a s im ila r p a tte rn , or whether the patterns vary. Population patterns may d i f f e r due to the geography, population density or various environmental fa c to rs . Observing the changes in pattern th a t 24 accompany a reduction in size of a population is essential i f the objec­ tiv e is to fo llo w long-term population trends. The sample scheme must be adjusted to r e f l e c t any fundamental change in d is t r ib u t io n . Each index o f aggregation is a single s t a t i s t i c th a t describes only a single aspect o f s patial patte rn . Each index should be thought of as providing only a measure o f the extent to which pattern departs from randomness. Pielou (1974, 1977) stated th a t the patterns of a population spread over a continuum has two obvious properties which may be called in te n s ity and g r a in . The in te n s ity of a pattern is the extent to which density varies from place to place. independent o f i t s in t e n s it y . The grain of a pattern is The grain is coarse i f i t s clumps and the gaps among them are la rg e ; i f converse, the pattern is fin e -g ra in e d . Indices o f aggregation calculated from data obtained by sampling with quadrats o f one size are a l l measures of the in te n s ity o f a p a tte rn , and not the g ra in . To study "grain" by means o f quadrat sampling i t is necessary to use several quadrat s ize s , as introduced by Greig-Smith (1954, 1964). Clark and Evan's index o f R c le a rly measures only the in te n s ity of p a tte rn . For the purpose o f comparing the in te n s ity of d i f f e r e n t p attern s, the indices which are used should not be affected by the population density. Two patterns can have the same in te n s ity although t h e ir densities d i f f e r . Among d i f f e r e n t indices Lloyd's Index o f Patchiness (C ), and M o r is ita 's Index o f Dispersion ( I d e lta ) are the most useful measurement. The R value o f Clark and Evans is probably the best i f one p a r t ic u la r ly wishes to measure the pattern in t e n s it y , because the d is ­ tances between in d iv id u a ls are included (P ie lo u , 1974, 1977). 25 Armyworm-Parasite Relationship The armyworm is attacked by a complex o f natural enemies which as a whole plays a decisive ro le fo r c o n tro llin g armyworm population. Many p a ra s ite s , predators and diseases of armyworm are recorded in pub­ lished l i t e r a t u r e . The most complete l i s t o f armyworm natural enemies were presented by Breeland (1958) and Guppy (1967). Breeland presented a l i s t of 16 p a ra s ite species, two predators and three diseases, and Guppy (1967) recorded 69 species o f primary insect parasites and 12 associated hyperparasites which are presented in Table 3. Two species o f p a ra s ite s , Winthemia rufopicta (Big) (Diptera: Tachinidae) and Apanteles m i l i t a r i s Walsh (Hymenoptera: Braconidae), and a Nuclear Polyhydrosis Virus are the most important natural enemies o f armyworm. Their presence in the f i e l d during the epidemic years has often been reported. Winthemia ru fo p icta (Big) has been confused with another species Winthemia quadripustulata F. All old records of the armyworm always used Winthemia quadripustulata i f they referred to Tachinid parasites of the armyworm. Recent papers p re fer using Winthemia rufopicta instead (Danks, 1975; Ravi i n , 1978 personal communication). This confusion needs some c l a r i f i c a t i o n and v e r if ic a t io n by taxonomist. Winthemia ru fo p icta is an aggressive p a ra s ite , having a high search a b i l i t y , rapid development, and high reproductive p o te n tia l. The female prefers to lay eggs on the 5th and 6th armyworm larvae. The f l i e s have a diurnal pattern of a c t i v i t y , which contrasts strongly with th a t of i t s armyworm host (Danks, 1975). Number of eggs la id on a host 26 Table 3. List o f Recorded Insect Parasites of the Armyworm (Guppy, 1967) Order Family Species Hymenoptera Braconidae Meteorus autographae Mues. Meteorus communis (Cress.) Meteorus 1aphygmae V ie r. Apantele's flaviconchae Riley Apanteles forbesi Apanteles- laeviceps Ashm. Apanteles m arainiventris (Cress.) ApantelelT rufocoxalis Ril ey Microgaster auripes Prov. M ic r o p litis alas kensis Ashm. M ic r o p litis me!ianae V ie r. Mi c r o p ! i t i s v a ric o lo r V ie r. Rogas aciculatus (Cress.) Rogas a tric o r n is Cress. Roqas po litic e p s ' Gahn. Rogas te rm in a li7 (Cress.) Rogas sp. Ishneumonidae Pimp!a pedal is Cress. N e te lia geminata (Say) N e te lia ocel1ata ( V i e r . ) N e te lia sayi (Cush.) Phaeogenes hebrus (Cress.) Melanich7ie~umon bre v ic in c to r (Say) Splichneumon superbus (P r o v .) Cratichneumonprevipennis (Cress.) Ichneumon ambulatorius P. IchneumoTi' annulatorius F. IchneumoTT canadensis Cress. Ichneumon- laetus (B ru lle ) CampoletTs oxylus (Cress.) Hyposoter exiguae ( V i e r . ) Tnerion Jassacus V ie r. Emcospilus purgatus (Say) EnicospiTus sp. Eulophidae Eulophus sp. Euplectrus mellipes Prov. Euplectru? plathype'nae How. Scelionidae Telenomus minimus Ashm. Telenomus~ sp. continued 27 Table 3--continued Order Family Species Di ptera Tachinidae P e le te ria texensis Cn. Archytas a p ic if e r W1 k . Archytas' marmoratus (Tnsd.) Athrycia cinerea TCoq.) Periscepsia laevigata (Wulp) Periscepsia helyrous TVll k .) Compsilura concmnata (Mg.) Eucelatoria rubentis (Coq.) Euphorocera claripennis (Macq.) Euphorocera sp. Exorista me!1 a ( W1k.) Exonsta larvarum (L .) Chaetogaedia monTicola (B ig .) Triachora u n ifa s c ia ta (R .D.) Winthemia quadripustulata ( F . ) Winthemia~ rufop icta (B ig .) Gymnocarcelia ricinorum Tnsd. Lespesia a le tia e ( Ri1ey) Lespesia archippivora (R ile y ) Lespesia melalophae (Al 1en) Madremyia saundersi i ( Wi1 1 .) Patelloa~leucaniae (Coq.) Phryxe vulgaris (F a !1 . ) Phryxe pecosensis (Tnsd.) Sarcophagidae Helicobia rapax (W lk.) Blaesoxi"pha (Blaesoxipha) hunteri THough) 28 larva is p o s itiv e ly correlated with the size of th a t la rv a . Maggots hatching from the eggs w i l l penetrate the c u tic le and develop in the body of the host. The survival o f maggots inside the la rv a l body depends on the a b i l i t y of the host to support maggot development; the number o f maggots entering the host; and the in te ra c tio n with other species competing for the same host (Danks, 1975). Usually the host larvae are k ille d 2-3 days a f t e r maggots penetrate into the host body. Winthemia ru fo p ic ta is not a host s p e c ific p a ra s ite , i t attacks mostly Noctuid la rv a e . The success of i t s development and survival depends on the a v a i l a b i l i t y and s u i t a b i l i t y of d if f e r e n t hosts d is ­ trib u te d through time and space. Besides the armyworm, Danks (1975) recorded 6 other hosts o f th is species; namely, Laphigma frugiperda (A & S . ) , H e !io th is zea (Boddie), He!iothis virescens (F a b .) , Trichoplusia ni (Huebn. ) , Prodeni a o r n ito g a l1i Guen. , Peridroma saucia (Huebn.). Agrotis ip s ilo n (H u f n .) , F e l t i a ducens Walk, and F e lt ia subterrania (F a b .) also become p o ten tial hosts fo r W. r u fo p ic ta . In North Carolina the f i r s t generation o f W. ru fo p icta emerges during A p r i l , and probably p a ra s itiz e s hosts th a t overwinter as p a r tly grown larvae ( e . g . , the armyworm) or th a t begin development very early in the year ( e . g . , Peridroma saucia) . The parasite may build up on any common s u ita b le host th a t is abundant l a t e r in the year (Danks, 1975). Apanteles m i l i t a r i s Walsh, a gregarious braconid p a r a s ite , is an endoparasite, with a good searching a b i l i t y and high reproductive p o te n tia l. I t i s , more or less host s p e c ific to the armyworm. 29 I t attacks th ird to f i f t h instars of armyworm larvae. No Apanteles larvae emerged from armyworm larvae exposed to attack in instars 1, 2, and 6 (Calkins and S u tte r, 1976). Towers (1915) reported th a t the wasps did attempt to ovip osit on the 5th and 6th i n s t a r , but were generally unsuccessful (except in newly molted 5th in s ta r ) because of the tough­ ness o f the c u t ic le . Parasitized armyworm larvae w i l l be k ille d in the l a t e 6th in s ta r . The rate of A. m i l i t a r i s development w ith in larvae of armyworm decreased proportionately with increases in ambient temperatures between 21 and 27°C. The parasite seems to develop well a t moderately high temperatures, but in the f i e l d , i t s slow development a t lower tempera­ tures would probably prevent i t from becoming a major dete rre n t fa cto r during cool spring weather (Calkins and S u tte r , 1976). The parasite always emerges as a t h ir d in s ta r larvae and only from s ix th in s t a r host la rv a e , regardless of the host in s ta r th a t was o r ig ­ i n a l l y attacked. The number o f parasite larvae emerging from one host body ranges from 1 to 161 (Calkins and S u tte r , 1976), or from 6 to 101 (Breeland, 1958). Armyworms para s itize d by A. m i l i t a r i s show no signs of t h e i r p lig h t u n til nearly mature when they become sluggish, and death comes only a f t e r the p a ra s ite larvae have emerged and spun t h e i r cocoons. During the time before the larvae is k i l l e d , i t s food consumption is s ig n if ic a n t ly reduced. Tower (1916) states th a t armyworms p a ra s itize d by A. m i l i t a r i s eat approximately h a lf as much as do non-parasitized larvae during the same period. 30 Overwintering and Supercooling A b il i t y Insects are able to overwinter e ith e r in a diapause or hiberna­ tio n s ta te . Usually the diapause is induced by seasonal changes in photoperiod, temperature or d ie t . A combination of short photoperiod, low temperature, and dry d ie t may take an insect into diapause. Winter dormancy or hibernation is controlled by two fa c to rs , environmental and genetic fa c to rs . Most insects enter a period o f dormancy when some environmental factor,such as temperature, becomes unfavourable and they w i l l resume t h e i r a c t i v i t y when conditions are favourable. The armyworm's success in surviving the w inter conditions depends upon i t s a b i l i t y to withstand low w inter temperatures. S a lt (1961) divided cold hardiness of the insect into two classes: 1) avoidance of freezing by supercooling, and 2) freezing tolerance. The former group are called freezing -su sceptible and the l a t t e r group are called fre e zin g to le r a n t or fre e z in g -r e s is ta n t. The armyworm is included in the f i r s t group. The a b i l i t y o f an insect to supercool is an in d ic a to r of cold tolerance. Most researchers use the supercooling point as an index of cold tolerance even though the mean supercooling temperature of any species w il l not alone determine whether the species w i l l overwinter on a p a r tic u la r h a b ita t. Most insects do not survive freezing and the supercooling point is the le th a l l i m i t of low temperature. Supercooling point o f an insect is dependent upon many i n t r i n s i c and e x tr in s ic fa c to rs , and takes place as a p ro b a b ility function ( S a l t , 1961). MATERIALS AND METHODS Field Sampling and Parasite Observation Field Research, 1976 Larval and pupal sampling of armyworms were undertaken in a wheat and rye f i e l d in Cass County, Michigan. as the sampling method. A quadrat count method was used Larval sampling, un fortu nately, was done during la t e in s ta rs , due to the l a t e report of the location outbreak. sampling was done four times, June 8 , 12, 19, and 25. were found in the f i e l d a f t e r June 25. The No larva or pupa Sampling and observations were carried out during the daylig ht hours. One square foot o f soil surface was used as a sampling u n it , and ten samples were taken per observation date. All larvae were c o lle c te d , counted and checked fo r in s ta r and Winthemia p a r a s itiz a tio n . Instars of armyworm were checked by measuring the head capsule, using Guppy's (1969) c r i t e r i a . Parasitism was checked by the presence o f parasites eggs on la rv a l body. Larvae were placed in paper containers and tra n s ­ ferred to the laboratory fo r additional parasites observations. Soil samples were taken by digging soil 1-2 inches deep and plac­ ing the soil in a p la s tic bag, and tra n s fe rrin g the bags to the Collins Road Field S tation. The next day soil samples were run through a so il s i f t e r , and checked f o r annyworm pupae. 31 The number o f pupae were 32 counted, and the pupae were reared in a 70°F room fo r checking p a r a s itism and s u r v iv a l. Field Research, 1977 To measure population density and study the s patial d is tr ib u tio n of larvae in the f i e l d , a 10 x 10 fo o t p lo t was set and observed on May 24th, June 4 th , 10th and 17th. Locations o f larvae in the plots were marked with bamboo sticks and they were mapped onto a 10 x 10 graph paper. Due to the low count of larvae found in the 10 x 10 s q . f t . p lo t , quadrat count technique was not appropriate as a sampling plan. Instead, night sweeping was used as the sampling method fo r larvae dur­ ing the rest of the season. Sampling of larvae in 1977 was done in the wheat f i e l d located in Cass County. 12:00 p.m. Sweep sampling was carried out a f t e r dark between 10 and The sampling u n it was one hundred sweeps, taken ten times at each observation date. Sampling and observations were done on May 20, 24, 27, and June 1 , 4 , 7 , 14, and 21. A fte r June 21, no armyworm larvae were caught by the net. Collected la rv a e were placed in p la s tic cups, and a l l larvae were tran sferred to a 70°F room fo r checking instars the following day. Parasite i d e n t i f i c a t i o n , developmental r a t e , and percentage o f p a r a s it­ ism were obtained by rearing collected larvae. For each observation d a te , larvae were separated by i n s t a r , and placed in 5-inch Dixie cups, and fed on barley leaves. cup. A maximum o f 5 larvae were placed in each Every day, the larvae were checked fo r i n s t a r , frass removal, food renewal and p a ra s ite emergence and development. 33 The cocoon or puparium o f the emerging parasites were separated and kept in d iv id u a lly in small p la s tic cups with a perforated cover. The emergence o f adu lt parasites was recorded fo r each cup. The unknown parasite specimens were mounted fo r fu rth e r i d e n t if ic a t io n . Tachinids eggs and Apanteles cocoons were also counted at th is time. E ffe c t o f P a ra s itiz a tio n by Winthemia and Apenteles on the Amount o f Food Consumed Winthemia ru fo p ic ta Experiments were done from August 15, 1976 to August 30, 1976 in the 70°F room. Cass County. The tested larvae were taken from an asparagus f i e l d in Only the sixth in s ta r larvae were tested in th is e x p e ri­ ment. Larvae were separated into p arasitized and unparasitized larvae by using the presence o f parasite eggs on the armyworm body. Larvae were placed in d iv id u a lly in 5-inch D ixie cups, with a perforated l i d . Barley leaves were used as a food. Total le a f area given to the i n d i ­ vidual la rv a were measured everyday with a Licor (B) Area Meter, before and a f t e r feeding. Total d a ily la rv a l consumption was assumed to equal the d iffe re n c e between these le a f area measurements. Each day frass was removed, and wet cotton and paper towels were renewed in each cup. Leaves were measured and changed each day u n til the p a ra s itiz e d la rv a died or the unparasitized larva pupated. Food consumption records were maintained fo r each larvae since some o f the "unparasitized larvae" (no Tachinid eggs attached) were l a t e r k il l e d by Winthemia. 34 Apanteles m i l i t a r i s These experiments were conducted at two places. Apanteles rearing was done a t CLB greenhouse, while the consumption te s t was done inside the 70°F room at the Natural Science Building. The experiments were carried out between July 8 , 1977 and July 29, 1977. Groups o f Apenteles cocoons from several hosts were held in 10 oz. c le a r p la s tic cups, with a perforated cover to provide continuous aera­ tio n . Hasps were kept in the cups fo r 5 days to assure th a t mating was successful. Twenty female wasps were removed from the cups with an a s p ira to r, and placed with armyworm larvae. Ten th ird in s ta r armyworm la rv a e , and ten Apanteles wasps were placed in a 5-inch Dixie cup. Arniyworm larvae were exposed to the parasites fo r 24 hours a t a rearing room temperature (73°C ). These twenty exposed larvae were removed from the cups and placed in d iv id u a lly in 5-inch Dixie cup. Barley leaves were used as food. Total l e a f area given to the individual larva every day was measured with Licor (§) Area Meter, as described in 1976 section. All other pro­ cedures are id e n tic a l to those described f o r 1976. Bucket Experiment During July to September 1977, armyworm populations were very low in the Cass County f i e l d and no larvae were caught in net samples. Therefore, a new method was devised fo r continuing the observation o f f i e l d parasitism during the rest of the season. larvae were exposed to f i e l d conditions. Greenhouse reared Containers with fo lia g e 35 provided enough fresh food, and shade fo r the te s t larvae during the exposure period. The method was successful due to the high larval recovery r a te s , a f t e r a short exposure period, however, some larvae escaped. Several techniques were te ste d , and the best design is diagrammed in Figure 2. Two buckets were used, the f i r s t is the outer bucket which contains water fo r maintaining the plan ts, and the inner bucket fo r holding plants th a t were inserted in 5 p la s tic tubes. Verm iculite was placed in the inner bucket between the tubes, fo r reducing the chance of la rv a l escaping. Food plants were any grass or small grain which had green leaves and roots. Larvae were placed between or on these plants. All armyworm la rv a l instars were exposed on each observation date. In each bucket 20 ind iv id u a ls o f each in s ta r were placed. On the next observation date, before the new larvae were put in , the remaining larvae in the bucket were tran sferred and reared in the 70°F room at the Natural Science Building. The method of checking the armyworm parasitism was id e n tic a l to the method described e a r l i e r . The bucket experiment was carried out twice a week, from June 8 to October 11, 1977. Spatial D is trib u tio n Study The study of the d is t r ib u t io n of the armyworm was done in two Cass County location s; in a wheat f i e l d , and in an asparagus-crabgrass fie ld . Two d i f f e r e n t methods were used in successive years; namely, 36 > PLANTS .> BUCKET 1 ^ m BUCKET 2 VERMICULITE > WATER BUCKET 2 VERMICULITE * <5, Figure 2. PLASTIC TUBE The diagram of the bucket experiment used fo r checking f ie l d parasitism o f armyworm larvae in Cass County 1977. 37 quadrat counts fo r the wheat f i e l d in 1976, and individual mappings in 10 x 10 f t . sw. plots in 1977. Quadrat counts were also used fo r the asparagus f i e l d in 1976 and 1977. Quadrat Count Method Three sample u n it sizes were used; 1 sq. f t . , 4 sq. f t . , and 1 sq. yard in a wheat-rye f i e l d near Marcel!us, Cass County on June 12, 1976. Samples were taken randomly, fo r each u n it size f iv e re p lic a tio n s were used, except th a t only 3 rep lic a te s o f the large u n it (1 x 1 sq. yard) were taken. To in v e s tig a te the d is tr ib u tio n o f the la rv a e , the f i e l d was divided in to f iv e regions according to the condition of plants and e le ­ v a tio n . Figure 3 shows these regions in the f i e l d . Five 1 sq. f t . sample units were taken at random from each region, and the number and in s ta r o f larvae were recorded. Quadrat counts were also used to study the la rv a l d is trib u tio n between f i e l d s . Eight wheat f ie ld s in Cass County were checked during the peak o f the f i r s t generation larvae on June 14, 1976. Five 1 sq. f t . samples were randomly taken from each f i e l d , and the number and in s ta r o f larvae recorded. The same observations were done in four f ie l d s near Mason in Ingham County June 16, 1976. Ind ividu al Mapping One spot in the 1977 wheat f i e l d was selected randomly. One p lo t o f 10 x 10 sq f t . was measured by using a rope and bamboo sticks as a border. A ll wheat rows inside the plo t were examined fo r armyworm la r v a e , i f a larva was found the location o f the larva was marked with a 38 p a s t u r e Fi9Ure 3 ' *» the wheat f , . ld 1n Cass 39 bamboo stock and removed. A fte r a ll larvae were marked and removed, t h e i r locations were mapped onto a 10 x 10 scale graph paper fo r la t e r analysis. Mapping o f individuals in the wheat f i e l d was performed 4 times, May 24, June 4, 10 and 17. The asparagus-crabgrass f i e l d were located in S ilv e r Creek Town­ ship, Cass County, Michigan. These asparagus f ie ld s were heavily i n ­ fested with crabgrass and other weeds. The two f ie ld s together were about 5 ha and were surrounded and separated by an apple orchard. One f i e l d was designated as a high density f i e l d , and one a low density f i e l d . randomly. From each f i e l d one 10 x 10 f t . of sample was selected The mapping routine was as previously described fo r wheat 1977, except the grass was cut to insure th a t every larva in the plot was counted. Observations were made on August 9, 12, 17, 23 and 29 of 1976, with 2 samples taken on each date in the high f i e l d , and one in a low f ie l d (15 data s e ts ). Pupal locations in the 10 x 10 plots was investigated by dividing each plot into 100 squares o f 1 x 1 sq. f t . from 1 to 100. These squares were numbered All plants on the p lo t were cut and removed. Each square was dug 2-3 inches deep, and the so il was screened through a soil s i f t e r (Gin s h i f t e r ) . Some o f the soil squares were put in a numbered p la s tic bag and taken to the Collins Road Field S ta tio n . The samples were held in a 40°F room u n til they could be processed, which was less than 3 days. The number o f pupae found in each soil square was recorded, the pupae were located in the middle of the square. In 1977 observations were taken only in a high density asparaguscrabgrass f i e l d . 40 Observations on la rv a l d is tr ib u tio n were taken on July 29, August 5 and 12 of 1977, and on pupal d is trib u tio n August 16, 1977. the observations were s im ila r to what was done in 1976. Basically Besides the location and in s ta r of arrnyworm larvae the presence of Tachinid's eggs were also checked and recorded. The location of Apanteles coccoons and Rogas terminal is puparium were recorded in the mapping. D is trib u tio n of plants in the p lo t area was recorded as they were in 1970. Computer Analysis of Spatial D is trib u tio n Field mapping data fo r 1976 and 1977 were inputed in to the CDC 6500 computer using the CDEXSPOCS program developed by Dimoff, 1977. Two computer programs were developed fo r the analysis of these data, one based on the nearest neighbor method andthe other based on quadrat counts. The flow chart o f the nearest neighbor method is presented in Figure 4, and the program l i s t i n g is presented in Appendix A. the formulas A ll of which are used to calculate d is t r ib u t io n s t a t i s t i c s are based on Clark and Evans'paper (1954). In the quadrat count analysis the programs have been developed using the following assumptions: a) The f i e l d where the population is located is composed of large numbers o f s im ila r 10 x 10 f t . plots with a same type of d is t r ib u t io n . b) A p lo t where one sampling u n it is taken, w i l l not be i n ­ cluded in the next sampling. is without replacement. The sample design therefore PLEASE NOTE: In a ll cases this material has been filmed 1n the best possible way from the available copy. Problems encountered with this document have been Id en tified here with a check mark y*1_. 1. Glossy photographs 2. Colored Illu stratio n s 3. Photographs with dark background 4. Illu stratio n s are poor copy ____ 5. Print shows through as there 1s text on both sides of page ________ 6. In d is tin c t, broken or small p rin t on several pages 7. Tightly bound copy with p rin t lost 1n spine 8. Computer printout pages with In d istin ct p rin t 9. _____ lacking when material received, and not available Page(s) from school or author ________ 10. Page(s) _______ seem to be missing 1n numbering only as text follows _______ 11. Poor carbon copy _______ 12. Not original copy, several pages with blurred type 13. Appendix pages are poor copy ________ 14. Original 15. copy with lig h t type ________ Curling and wrinkled pages _______ 16. Other University. Micrdnlms International 300 N Z E E B RD. . A N N A R B O R . M l 4 8 1 0 6 <3131 761-4 700 throughout 41 START ^ READ X,y FOR ONE SET USING RANF GENERATE ONE RANDOM POINT , MEASURE THE ISTANCES WITH OTHER POINTS PRINT ALL DISTANCES STOP ARRANGE FREQ COUNTS OF DISTANCES PRINT PRINT FREQUENCY COUNTS FIND NEAREST NEIGHBOR ( ccm i Figure 4. SERR * .2613/ • RHO RE The flow chart o f nearest neighbor analysis. 42 c) To avoid the e f f e c t o f a border between p lo ts , or to avoid d u p lic a tio n in taking samples, sample space was lim ite d to the area inside the p lo t with a border space th a t is equal to o n e -h a lf o f the sample u n it length (see Figure 5 ). Random points are taken from any spot in the sample space. Individuals in the border space w il l be included in the sample counts, i f the respective random points are on the margin o f the sample space. Because o f th is r e s t r i c t i o n the maximum sampling u n it (quadrant) which could be used is o n e -h a lf o f 10 x 10 sq. f t . or 5 x 5 sq. f t . S t a t is t ic s which are calculated by the program are the mean of the population (My), mean and variance o f the sample, variance/mean, I d e l t a , K value o f negative binomial, and Chi-square te s t values fo r variance/mean and I d e lta . My is calculated as the average number of in d ividu als in the sampling u n it inside the sample space. The mean and variance of the samples are calculated from the sample counts. I d e lta is calculated by M o r is ita 's formula I d e lt a = nE(x2) - E ( x ) /E ( x ) 2 - Ex and k of negative binomial is estimated by, K = ( * 2) / ( s 2 - x) chi-square te s t value fo r I d e lta is calculated as Id (x - 1) + n and fo r variance/mean is calculated as ( s 2/ x ) (n - 1 ) . Ex 43 ------^ BORDER 10 F t . SAMPLE SPACE SPACE ✓ Figure 5. Sample space inside 10 x 10 sq. f t . , with 1 x 1 sq. f t . sampling u n it. as a 44 The debugging value fo r I d e lta and K are set = -9 .9 9 9 , i f (E x )2 = Ex and s2 = x . The flow chart of the program is presented in Figure 5A, and program l i s t i n g is in Appendix B. Optimum Sampling Units For c a lc u la tin g RNP, we need data on Cu, or r e l a t i v e cost of measuring one u n it. Cu is calculated as a r a t io of u n it size over a number of square f e e t which could be sampled with a f i x resource. In practical f i e l d sampling the principal resource is time; th a t i s , the amount of time spent fo r processing one sample, the time spent to tra v e l between samples. Data fo r th is time resources was calculated in 1977, fo r the asparagus-crabgrass f i e l d in Cass County. The time spent processing one sample u n it includes the time required for cuttin g the grass, cleaning the soil surface, fin d in g the la rv a e , and counting and recording the larvae. The sampling time o f eight quadrat units ( i . e . , .4 , .6 , 1 .0 , 1 .6 , 2 .0 , 3 .0 , 3 .6 , and 4 .0 sq. f t . ) was recorded, e t c . , with 5 re p lic a ­ tions fo r every u n it. Wood frames o f various quadrat sizes were used to measure the soil surface fo r processing. one person. The e n t ir e sampling process was performed by Between sample time was estimated from 30 samples taken from a single f i e l d . 45 ( START 0> ) < READ X,Y OF ONE SET PRINT, i*,£ x SAMPLE, X, S' MU. S’ / i , IDELTA X HAT, CHI* TEST READ NUNB OF SAMPLES READ SAMPLE SIZE / / 7 XX - YY \ * •'SAMPLE CHI’ TEST ■ IDELTA U x - i) ♦ N - / X RANGE ■ 10 - 2XX Y RANGE - 10 - 2YY AREA - X RANGE * Y RANGE IDELTA ■ n £ ( x ’ > t x / C x ) ’ - ix N <■ Mu • Tot . I h d iv / AREA — * < U x )’ '' X - 1, NUMB IDELTA • -9999 KHAT ■ x’ (s '-x ) <> GENERATE RANDOM POINT KHAT - -9999 'COUNT POINTS IN SAMPLE UNIT A {cONT)----------------------- y Figure 5A. /CALCULATE 7 x, s’ , s '/x / - CHI* TEST • (s’ /x )* Cn-1) The flow chart of quadrat count analysis. 46 Host Preference Armyworm cultures were maintained by using natural food fo r the la rv a e . A ll larvae were obtained from adults which were collected in the f i e l d . The studies consisted o f 3 parts: an oviposition t e s t - - t o in v e s tig a te the preference o f adu lt moths in egg laying; a developmental growth t e s t — to investigate the e f f e c t of d if f e r e n t host plants to the growth and development of la rv a and pupa; and a food consumption t e s t — to in v e s tig a te the ra te of food consumption o f the armyworm on d if f e r e n t host p la n ts . Oviposition Test Barley (Larker c u l t i v a r ) , Downy (h a iry le a f surface) wheat, Genesee (smooth l e a f surface) wheat, oats (C lin tla n d 6 4 ), corn (Dekalb XL 22B), and rye (Wheeler c u l t iv a r ) were tested. Timothy ( Phleum pratense) , Brome Grass ( Bromus inerm is) , and Quack Grass ( Agropyron repens) were used in the f i r s t experiment, but l a t e r , due to poor seed germination, these plants were not used. Three seedlings of te s t plants were sown in 1.5 inch Dixie cups. D if fe r e n t plants were set in 16 x 17 x 10" ovip osition cages with nylon screen on three sides. Cups were arranged in the cage in randomized block design, with 3 rep lic a tio n s fo r each entry. A p a ir o f moths was released in the cage and fed with a solution of 1:10 o f honey and water. The moths were given a fre e choice to mate and lay t h e i r eggs. counts were done on the second day a f t e r ovip osition began. The egg The tempera­ ture in the rearing room was maintained at 70-73°F, with 50-60% r e la t iv e humidity and 16 hours of l i g h t . 47 This te s t was conducted 4 times with a d if f e r e n t composition of p la n ts , number of cups and number o f moths. The description o f these experiments is presented in Table 4. The Developmental Rates Three newly hatched larvae were placed in a cup containing 3 host seedlings. A lantern globe was used as a cover fo r each cup, i t s top was closed by a nylon sleeve to allow fo r c irc u la tio n o f a i r inside the cage. Six small grains ( i . e . , Downey Wheat, Genesee Wheat, B arley, Rye, Corn and Oats) and two grasses (Timothy and Brome Grass) were tested. The plants were changed once every two days in the e a rly instars and every day in the la t e in stars. Larvae were weighed tw ice, at 10 and 15 days, in the f i r s t e x p e ri­ ment (from 2/10/76 to 3 /3 0 /7 6 ) and once at 13 days in the second experi­ ment (4 /5 to 5 /1 5 /7 6 ) . checked. Every day the stage of each ind ividu al was Observation o f la rv a l instars was performed by measuring the width o f the head capsule, using Gyppy's data (1969). larvae fo r every plant was recorded. the completion o f pupation. The m o r ta lity of Pupae were weighed two days a f t e r The m o rta lity o f pupae was also recorded. The temperature in the rearing room was maintained around 70-75°F, with 50-60 r e l a t iv e humidity, and a 16 hour lig h t cycle. Food Consumption Rates Ten newly hatched larvae were fed in d iv id u a lly on each te s t pla n t. Leaves were taken from greenhouse seedlings o f Barley, Genesee wheat, Downy wheat and oats. The individual larva and seedling leaves were put in 5-inch Dixie cup with a c le a r p la s tic cover. To maintain high 48 Table 4. Description of Four Oviposition Tests o f the Armyworm a t CLB Greenhouse Experiment Number Date Number o f Replication Number of Pairs of Moth A 2/4 - 2/11/76 6 2 B 2/21 - 3 /2 /7 6 5 2 C 2/9 - 2/1/76 3 6 D 2/13 - 2/23/76 4 6 49 humidity inside the cup and the freshness of leaves, a moist paper towel was used to cover a piece o f wet cotton placed at the base of a l l leaves. Each day leaves, paper towel and cotton were checked and changed. The frass was cleaned from the cups, and the la rv a l in s ta rs were checked by measuring the head capsule w idth, or by finding old head capsules. Leaf consumption by the la rv a , was measured by determining the l e a f surface area before and a f t e r feeding. Leaf surface area was measured by Licor Model L I -3000 Portable Area Meter. This meter u t i ­ liz e s an e le c tro n ic method of rectangular approximation to measure the le a f surface. However, f i r s t and second in s ta r larva feed by s k e lo t in iz - ing the l e a f and t h e ir damage cannot be detected by the meter since l i g h t does not pass through the damaged areas. The damage by these in ­ stars was measured i n d ir e c t ly by taping each damaged le a f to a c le a r p la s tic sheet. The sheet was then photocopied, and the damaged areas were marked with a pencil then cut out. These cut out pieces were then run through the area meter. The damage produced by the th ird to sixth in s ta r forms clean holes or the e n tire l e a f is eaten. The area meter could be used d i r e c t l y to measure to ta l surface area consumed by the larva each day by obtaining the d iffe re n c e between the to ta l area o f leaves before and a f t e r being fed to the la rv a . Care was taken so th a t the amount of le a f tissue given each day was more than the larva needed fo r th is period. Food consumption measurement was done from the f i r s t day the larva hatched to the prepupa stage. 50 Experiments on the E ffe ct o f Temperature on the Armyworm Development E ffe c t of Temperature to Oviposition This study was done at the CLB greenhouse and the Natural Science Building from July to October 1977. The main objective o f th is study was to in v e s tig a te the e f fe c t of constant temperature on the development of adult moths and t h e i r oviposition ra te . The t e s t was done in environmental chambers a t the CLB greenhouse which were set at 15, 22.8, and 25°C. was 50-60%. The l i g h t period was 16 hrs./day and the r e l a t i v e humidity Two males and one female were placed in a 1 cb. f t . oviposi­ tio n cage, and moths were fed with a 10:1 honey s olu tio n. lings were used as an ovip osition s i t e . Barley seed­ Three re p lic a tio n s were used at each temperature. In order to gain the e f fe c t of a wider range o f temperatures, other ovip osition te s ts were done at the Natural Science Building by using 5 "wooden growth chambers". These chambers are made and measured 24 x 24 x 18 inches. I t was equipped with a out of wood heater, a fan, s e lf - t im e r switch, and an automatic temperature c o n tr o lle r . temperatures were s e t, they were 10, 12, 16, 30, and 32°C. Five The f i r s t three growth chambers were in the 50°F room, and the other two chambers, with temperatures o f 30 and 32°C, were placed in the 70°F room. one ovip osition cage could be put into the chamber. Only For every tempera­ tu re the ovip o s itio n t e s t was done three times. The te s t was stopped i f two out o f three moths were dead. Every day barley leaves were checked fo r eggs, and i f eggs were found, the number was recorded. 51 Late Fall Development Armyworm ind ividu als of d if f e r e n t instars were taken from the CLB greenhouse to the insectary on Collins Road. The insectary rearing program was started on August 15, 1977 and continued u n til November 5, 1977. Larvae were reared inside 16 x 16 x 16 inches nylon cage and fed with barley seedlings. In order to follow the in s ta r development, ten new larvae were reared in d iv id u a lly in 5-inch D ixie cups. The leaves in the cup were changed each day when the larvae were checked fo r in s ta r development. The larvae were kept in the cup from September 9 , 1977 u n til they were k ille d by the f i r s t f r o s t on November 11, 1977. Several days before the f i r s t f r o s t , 200 larvae and pupae were placed on the ground and covered with grass to study the m o rta lity e f f e c t o f the f i r s t f r o s t and probable w inter m o r ta lity . Ten larvae or pupae were placed in 5-inch p la s tic cups which were f i l l e d with s o i l . Nylon screen was used to cover each cup to avoid the larvae moving out of the cup. One cup (10 in d iv id u a ls ) o f larva or pupa were checked the f i r s t day a f t e r the f r o s t , and at two week periods in w inter. The m o r ta lity o f each in s ta r was recorded every observation date. R efrig era tio n Test In order to study the a b i l i t y o f armyworm pupa to survive under a cold temperature, 250 pupae from the culture in the CLB greenhouse were kept in a r e f r ig e r a t o r . The average temperature was 40°F, and the r e l a t i v e humidity was 50%. The pupae were kept in the r e fr ig e r a to r fo r three and four months, s ta r tin g from April 21, 1977 to July 21, 1977. The pupae were removed 52 from the r e fr ig e r a to r and placed in the rearing cage a t room temperature (7 3 °F ). The number of moths th a t emerged e ith e r normally and mulfunc- t io n a l ly were recorded. The dead pupae were removed and counted. Supercooling Test Larvae and pupae fo r the supercooling te s t were obtained from the greenhouse rearing program and Collins Road Insectary. The greenhouse specimens were kept a t 40°F fo r 24 hours before te s tin g , the insectary specimens were tested r ig h t away because they had been exposed to n a tu ra lly f a l l i n g temperatures. The te s t was done from October 18, 1977 to October 20, 1977. The supercooling point is determined by placing the specimen on the bottom of a p i t of an aluminum bar. The c ir c u la r aluminum bar serves as a heating sink with a length o f 16.5" and a diameter of 1 .5 " . well fo r the specimen is 1.8" deep and 0.8" diameter. The Before a specimen was placed in the w e ll, the well was lined with modelling clay to insure tra n s fe r of released body heat to the thermocouple. was attached to the base o f a p la s tic plug. The thermocouple The plug was lowered in the well u n til the thermocouple touched the body o f the te s t specimen. thermocouples were attached to a Honeywell ® The potentiometer to provide a continuous record of the te s t specimen body temperature. The bar was placed into a fre e ze r chamber which contains a mixture of dry ice and ethyl alcohol 90%. The ambient temperature o f the fre e z e r could reach -70°F. The temperature in the well dropped an average of 2.85°F per minute. Upon fre e z in g , the larvae or pupae emitted heat of 53 c r y s t a l l iz a t i o n which was recorded as a sharp momentary increase in temperature. The lowest temperature reached p rio r to the increase was the supercooling point of th a t in d iv id u a l. RESULTS AND DISCUSSION Spatial D is trib u tio n o f the Armyworm in Michigan Regional D is trib u tio n Since 1900 armyworm outbreaks have been scattered and lo c a liz e d , however, fo r the l a s t 4 years (1975-1978) outbreaks have been more common and in te n s ifie d (see Figures 6, 7 , 8 , and 9 ). these figures was obtained from: The data fo r 1) Insect A l e r t s * , 2) Pest Management A s s is ta n t, and 3) county agents. In 1975, outbreaks population levels were re s tric te d (with one exception) to the southwestern portion o f the state (Figure 6 ); in 1976, 23 counties in the Lower Peninsula and one county in the Upper Peninsula (Figure 7 ) ; in 1977, only two counties (Figure 8) had out­ break populations. The year 1978 was considered to have the most severe outbreak o f armyworm ever recorded in Michigan (see Figure 9 ). In 1975 and 1976, most of the damage was reported from small grains (wheat, rye and o a ts ). This was due to the rapid development of the armyworm, and placed the 5th and 6th instars in heading grain f i e l d s . In 1978, damage was reported in small grains but the crop most heavily damaged was corn. * Insect A lerts is published by the Cooperative Extension Service of Michigan State U n iv e rs ity . 54 55 Fiau re 6. D is tr ib u ti on o f armyworm o u tb re a k --!975. 56 F ig u r e 7. D i s t r i b u t i o n o f arrnyworm o u t b r e a k - - ! 976. F ig u r e 8. D i s t r i b u t i o n o f armyworm o u t b r e a k - - ! 977. F ig u r e 9. D i s t r i b u t i o n o f armyworm o u tb r e a k — 1978. 59 In 1978, the armyworm development was protracted due to the cool weather, th e re fo re , larvae reached 5th and 6th in s ta r when small grains were being harvested. These populations were forced to move from the grain to the adjacent corn f i e l d s . observed: In the corn f i e l d two phenomena were 1) the damage was apparently re s tric te d to th a t part of the corn f i e l d bordering the grain f i e l d or grassy areas, and 2) the most severe damage occurred when grasses were w e ll-e s ta b lis h e d in the corn fie ld . Figures 10, 11, and 12 present the d is tr ib u tio n of armyworm larva in wheat fie ld s during the 1976 outbreak in Cass and Lenawee Counties. These maps are based on survey data collected by the author and a Pest Management Field Assistant. These figures show th a t there is a s i g n i f i ­ cant v a ria tio n of la rv a l density between f i e l d s . Within and Between Field D is trib u tio n o f Larvae Table 5 summarizes the w ithin f i e l d d is tr ib u tio n study (see M aterials and Methods, pp. 3 5 -3 7 ). Analysis of the variance indicates th a t the differe n c e between regions is highly s ig n i f i c a n t , and there is no significance between samples w ithin each region. This te s t indicates th a t the uniform ity o f the la rv a l d is trib u tio n in the f i e l d is only lim ite d within a small area. of plants within the f i e l d . This seems to be related to the uniform ity The denser and t a l l e r the plants are in a c e rta in area, the higher the density o f larvae. The a v a i l a b i l i t y o f shade during the day appears to be the main fa c to r re s u ltin g in a higher density o f larvae in any p a r t ic u la r lo c a tio n . d is trib u tio n □ OSILVER CREEK O M arce llu s OVOLINIA OWAYNE ^ ★ ^ • O MA R C E L L U S OP OK AG ON OP E N N □ □ CLANGRAGE ONEWBERG Q c a ssopolis □ □ OHOWARD ★ OJEFFERSON □ OPORTER OCALVIN OMASON OONTWA OMILTON Larvae/ 1 sq . f t . 3 Larvae / 1 sq . f t . : 4 - 3 Larvae/ 1 sq . f t . : 6 - 9 Larvae/ 1 sq . f t . ▲ : 0 ★ : 1 - □ • Figure 11. o c Cities Townships Armyworm larvae d is t r ib u t io n in Cass County wheat f ie ld s (1976). 62 OCL 1 NT 0 N ^ oMACON O F RA NKL I N OCAMBRI DGE ▲ WO O D S T O C K cTE CUM S EH * ▲ ★▲ * • • ★ OR A I S I N V oROLLIN □A * RI DGEWAC * □ □ ' OADRI AN CROME □ Q a dr i an CBLITFIELD ▲ ?HUSDS ON ▲ o M A D I SON CPALMYRA ODOVER □ • ★ c SENECA lis s fie ld QOgden A. : 0 ★ : 1-3 L arva e/1 sq. ft. | | : 4-5 L arvae/1 sq. ft. # 9 L arvae/1 sq. ft. : Figure 12. oRIGA oFAIRFIELD CM E D I N A Larva O o C ities Township s Armyworm la rv a e d is t r ib u t io n in Lenawee County wheat f ie ld s (1976). 63 Table 5. Reaions Total o f Armyworm Larvae in Five Sample Renions of the Wheat Field (Cass County, 1976). Samp!e Numbers 3 4 5 Total 1 2 A 15 11 9 14 15 64 B 4 5 3 9 7 28 C 2 2 3 5 8 20 D 14 15 23 15 17 84 E 13 21 14 14 13 75 Total 48 54 52 57 60 64 Table 6 summarizes the between f i e l d d is trib u tio n study (see M aterials and Methods, p, 3 7 ). Analysis o f variance te s t fo r a com­ p le te ly randomized plant design was u t iliz e d to in te rp re t the data in Table 5. The te s t indicates th a t the density o f the armyworm larvae between f ie ld s is s ig n ific a n tly d if f e r e n t . Seasonal Appearance of the Armyworm in Michigan In order to b e tte r understand the armyworm phenology, continuous and intensive observations must be carried out over a large geographical area. This is complicated due to the d is tr ib u tio n o f the insect and the d i f f i c u l t y of detection o f c e rta in l i f e stages (a d u lts , eggs, and L-l and L-2 in s t a r s ) . During two years o f f i e l d observations, the author was only able to c o lle c t and locate la te instars o f the f i r s t and second generations. No eggs and e a rly instars were found. Third generation populations were monitored in Fall 1976 and Fall 1977, but no larva or pupa were found. By assuming th a t the development of the armyworm in the southern lower peninsula o f Michigan is uniform, several methods were u t i l i z e d to in te rp re t seasonal development o f the armyworm. Spring Emergence Few arinyworm larvae were collected from grassy areas near Mason (Ingham C o .), Gull Lake (Kalamazoo C o .), and Marcellus (Cass Co.) in midA p r i l, 1977. in s ta r . Most of the e a rly collected larvae were 4th and 5th T h i r t y - f i v e emergence traps were set out in Cass County to 65 Table 6. Armyworm Density in Wheat Fields in Cass and Ingham Counties (June 1976) County/Field Number 1 2 1 5 10 2 2 3 Number of Samples 3 4 5 Total 8 6 7 36 0 3 1 3 9 1 3 0 1 1 6 4 0 0 0 1 1 2 5 9 11 7 8 11 46 6 7 8 10 9 11 45 7 2 2 3 0 1 8 8 3 5 2 5 4 19 1 2 1 1 2 1 7 2 0 2 1 1 3 7 3 0 1 1 0 4 1 3 3 2 ? 4 11 Cass County Inaham County 3 66 to c o lle c t emerging moths. 1977. Two traps caught one moth each on May 20, This ind icates th a t the armyworm does overwinter in Michigan, and i t seems th a t they overwinter as 3rd or 4th in s ta r la rv a e . Even though th is in v e s tig a tio n does not provide s u f f ic ie n t information about overwintering conditions, i t c l a r i f i e s the uncertainty about the a b i l i t y of the armyworm to survive during Michigan w inters. Field Occurrence o f Arinyworm Stages in 1976 In 1976 armyworm larvae were abundant in the f i r s t and second generation. The 3rd and 4th in s ta r larvae were, f i r s t found in Lenawee and Van Buren Counties during the second week o f June, while the 5th and 6th instars were abundant in Cass County and other southern counties in la te June. July. Pupae were collected at the end o f June and the beginning of The 3rd and 4th in s ta r larvae o f the second generation were collected from h a y / a lf a lf a f ie ld s at the end of J u ly , and the 5th and 6th in s ta r were observed in asparagus f ie ld s in Cass County about the middle of August. The moths peak appearance in Cass County lig h t- t r a p s was a t the end o f J u ly , and another small peak occurred a t the beginning of September. Figure 13 was constructed from the records of degree-day accumula­ tio n in Cass County and the f i e l d occurrence o f armyworms. In th is fig u re the f i r s t occurrence o f adults was obtained from the data of b la c k -lig h t catches in Lenawee County. This fig u re c le a r ly indicates th a t the "distance" between the f i e l d occurrence o f one in s ta r in one generation and the follow in g generation is around 1300-1400 degree-days accumulation. This conforms to Table 7. The developmental data of PUPA PUPA L5-L6 L 5 -I.6 LA-L5 L4-L5 L3-I.A L3-L4 o> -v j ADULT ADULT ± 500 1000 1) 1) A p ril M.-iy Figure 13. ACCOM 1500 20000 2500 3000 11 L A T 1 O N (> 46°F ) June__________________________ Ju ly________ Any.usl Field occurrence of armyworm stages in Southern Michigan, 1976. 68 Table 7. Degree-days Requirement fo r the Development o f Armyworm Instars (Base = 46°F) In s ta r DD Required to Complete In s ta r's Development DD Accumulation fo r Completion of In s ta r's Development Egg 156 156 Larva 1 107 263 Larva 2 72 335 Larva 3 76 411 Larva 4 86 497 Larva 5 106 603 Larva 6 223 826 Pupa 390 1216 Preov-adult 214 1430 69 Guppy (1969) was used to c a lc u la te degree-days accumulation needed by each in s ta r at base 8°C. The ta b le shows th a t the armyworm takes approximately 1400 degree-days to develop from one stage to the same stage in the next generation. This inference explains th a t Table 7 can be used as a rough estim ator o f the appearance o f armyworm instars in the f i e l d . The seasonal occurrence inform ation, th e re fo re , could be used to v a lid a te a simulation model o f the armyworm eco-system. B la c k -lig h t Data In te rp re ta tio n Using b la c k -lig h t traps to monitor insects (e s p e c ia lly Lepidoptera) has been a common practice of the Cooperative Extension Service fo r many years. The function o f b la c k - lig h t data is to provide a rough estimate about the occurrence and abundance o f insect adults and fo r id e n tify in g pest species which could damage crops. B la c k -lig h t data is always biased. such as: This is due to many factors 1) the location and elevation of the s ta tio n ; 2) amount of lig h t surrounding the tra p ; 3) the in te n s ity o f l i g h t ; 4) type of trap: 5) d if f e r e n t attractiveness to the l i g h t by both sexes; and 6) weather conditions. B la c k -lig h t records from Michigan and other states indicates th a t these traps consistently captured armyworm moths. As an example, Figures 14 and 15 show the flu c tu a tio n s o f armyworm catches in Lenawee, Cass and Bay Counties in 1976 (Cass County b la c k -lig h t was started in the middle of the season). The physiological date (with Base Temp. = 46°F) is used as the X -a x is , and the number o f moths caught per degreeday is used as the Y-axis. Accumulation o f degree-days from January 1 NUMBER MOTHS CAUGHT / DD CASS CO. cn- LENAWEE CO. o 1000 CUMULATIVE DD O A 6 6 F) Figure 14. Number of armyworm moths caught in the black-1iqht traps in Cass and Lenawee Counties 1976. o BAY CO, N 't NUMBER MOTHS CAUGHT / DD CD CNI CD O O CD 0 10000 2000 30000 CUMULATIVE DD ( 46 F) Figure 15. Number of armyworm moths caught in the black-light trap in Bay County 1976. 72 to October 1, 1976, in Lenawee, Cass, and Bay Counties are lis te d in Appendix Even though there is an obvious d i f f e r e n t i a l moth catch between lo c a tio n s , they have a s im ila r trend; namely, th a t in one year there are more than 5 d is t i n c t peaks o f armyworm moth f l i g h t a c t i v i t y . This could be due t o , 1) a continuous adult emergence in one region through­ out the season, and 2) imigrations of moths from southern areas which have already completed the development. A continuous observation of the armyworm development at a controlled temperature in d ic a te th a t the development o f individuals in a population is nearly uniform, th e re fo re , th is makes the f i r s t p o s s ib ility doubtful. I t seems that armyworm moths in Michigan are coming from two sources: 1) a native population th a t emerges from a local overwintering population; and 2) populations th a t were moved or carried by the wind from southern states. The f i r s t f l i g h t peak (a t approximately 200 DD accumulation) is the migrating population, and the second peak is the native population. The migrating population may have caused the out­ break in 1976. Spatial D is trib u tio n Study Wheat, 1976 Variance/mean r a t i o is used as an index of dispersion. Table 8 indicates th a t as the sample s ize increases the d is trib u tio n moves from random towards a more aggregated population. 73 Table 8. Sample Unit D is trib u tio n o f Armyworm Larvae in Quadrat Units of a Wheat F ie ld (Cass County, 1976) Number of Samples x s2 1 sq. f t . 5 11.00 6.00 .56 2.18 Random 4 sq. f t . 5 38.4 92.74 2.15 9.66 Random 1 sq. yd. 3 134.0 1338.82 9.99 29.97 s 2/x Chi Square D is trib u ­ tion Aggregate 74 The re la tio n s h ip between the mean and variance of the larval count in one square foot is presented by Table 9 and Figure 16. Table 9 shows th a t a l l data is in agreement with the Poisson series or random d is t r ib u ­ t io n , (X 2 = 9.49 fo r P = .0 5 ). Even though s t a t i s t i c a l l y the table does not show a s ig n ific a n t d iffe re n c e from a regular d is t r ib u t io n , some f ie ld s ind icate a tendency toward a r e g u la r ity . The re g u la r ity o f the d is t r ib u t io n in wheat fie ld s is l i k e l y to be caused by the behaviour o f the la rv a e . In the daytime the larvae are not a c tiv e , and can be found in protected areas. plant crown. The most s u ita b le hiding place is in the High la rv a l density causes the insects to move away from each o th e r, and occupy empty crowns. T e r r i t o r i a l behaviour produces a uniform d is t r ib u t io n of individuals over a small u n it area. As the u n it area increases the influence o f t e r r i t o r i a l i t y decreases. Wheat, 1977 Figures 17 and 18 show the d is tr ib u tio n maps of armyworm larvae in the wheat f i e l d in Cass County. I t is obvious th a t due to the low d e n s ity , the la rv a l d is trib u tio n was random. Asparagus and Crabgrass, 1976-1977 Figures 19, 20, and 21 are three examples of the d is t r ib u t io n of la rv a e and plants in the sample p lo ts . These figures show th a t the d is t r ib u t io n o f the armyworm larvae was aggregated, to some e x te n t, throughout the f i e l d . These clumps were the r e s u lt o f the nocturnal behaviour o f the la rv a e . Most o f the larvae were found under crabgrass. This grass offered protection during the d a y lig h t hours, and was a ready 75 Table 9. Relationship Between Mean and Variance of Larval Density in a One Square Foot Sample o f Wheat Fields in Cass and Ingham Counties, 1976 s2/x Chi Squared D is trib u tio n Number x s2 1 2 3 4 5 11.00 5.60 12.80 16.80 15.00 6.00 5.81 7.18 13.18 11 .49 .55 1 .04 .56 .78 .77 2.18 4.15 2.24 3.14 3.06 Poisson Poisson Poisson Poi sson Poisson 6 7 8 9 10 4.00 1.40 1 .40 .80 7.20 6.50 .80 1 .30 .70 3.69 1 .63 .21 1 .30 .87 .51 6.50 2.29 3.71 3.50 2.05 Poisson Poisson Poi sson Poisson Poi sson 11 12 13 14 15 1.80 1 .20 .40 9.20 •9.00 1 .69 1 .21 .30 3.17 2.50 .94 1.01 .75 .34 .28 3.76 4.03 3.00 1.38 1.11 Poisson Poi sson Poisson Poi sson Poi sson 16 17 18 19 20 21 1 .60 3.80 1.40 1.40 .80 2.20 1 .30 1 .14 .30 1 .30 .71 .70 .81 .30 .21 .93 .85 .32 3.25 1.20 .86 3.71 3.55 1.27 Poisson Poi sson Poisson Poi sson Poi sson Poisson 9.0 6.0 0.0 3.0 VARIANCE 12.0 15 . 0 76 .0 4.0 8.0 12.0 16.0 20.0 MEAN Figure 16. Variance/Mean r a t io o f armyworm larvae in 1 sq. f t . in a wheat f i e l d . sample 77 FEET F ig u re 17. D i s t r i b u t i o n o f armyworm l a r v a e in a wheat f i e l d C ounty, May 2 4 , 19 77 . in Cass 78 10 10 FEET F ig u re 18. D i s t r i b u t i o n o f armyworm l a r v a e in a wheat f i e l d C ounty, June 1 0 , 1977. in Cass 79 CRABGRASS ASPARAGUS o — Y LARVAL COORDINATES (FEET) * CD %* CD I K * * * J K lllliill S S iS S B S i * * C M ~ * ** * T 2 T 4 T 6 X LARVAL COORDINATES Figure 19. 8 10 (FEET) D is trib u tio n o f armyworm larvae and plants in an asparagus f ie l d ( f i e l d 111-3). 80 CRABGRASS ASPARAGUS K Y LRRVRL COORDINATES (FEET) * m m * m ’ CD m & nm m m m lit CO M m m % #* * * * mm ■# m CsJ • 2 i 4 — •------------ j 6 X LRRVRL COORDINATES Fiqure 20. 1------- r — 8 i 10 (FEET) D is trib u tio n o f armyworm larvae and plants in an asparagus f i e l d ( f i e l d 333-1 ) . 81 CRABGRASS ASPARAGUS STINKGRASS Y LARVAL COORDINATES (FEET) o —, X LARVAL Figure 21. COORDINATES (FEET) D is trib u tio n o f armyworm larvae and plants in an asparaaus f ie l d ( f i e l d 444-1 ). 82 food source f o r the foraging la rv a e . Very few larvae were found under stinkgrass and asparagus because they did not provide adequate protec­ tio n and were not a preferred host. Two computer programs were developed fo r analyzing d is tr ib u tio n o f the armyworm la rv a e in a 10 x 10 sq. f t . p lo t. They provide un­ lim ite d p o s s ib ilit ie s o f studying sampling characters, which would have been d i f f i c u l t to perform in a f i e l d experiment. Effects o f u n it s ize s , u n it shapes, the number of samples, e t c . , to the f in a l r e s u lt were e a s ily derived from the program. The program provided the best estimate o f variance o f population fo r any desired sample u n its . A ll larval d is t r ib u t io n data from asparagus and crabgrass f ie ld s is presented in Appendix C. Nearest Neighbor Analysis The distance from one individual to another provides a variable fo r a measurement o f spacing, th a t obviates the use o f quadrats and, th e r e fo re , elim inates that e f f e c t of quadrat s iz e . The re s u lt of the nearest neighbor analysis was u t i l i z e d as a "standard" in comparing and discussing the resu lts o f quadrat count analysis. Output o f nearest neighbor analysis from a ll f ie l d s are presented in Appendix E. A number o f distance measurements (N) range from 5 to 200, depending on the density o f the p lo t. The program stopped execut­ ing data when N was higher than the number o f in d iv id u a ls . Column C (Appendix E) is the t e s t o f significance of the departure from randomness. 83 The weakness of th is method is in selecting individuals at random to measure distances. I f the random points are w ithin clumps, the R value w i l l be smaller than i f random points are between clumps. Table 10 presents the e f f e c t o f a number o f distance measurements (N) and the value o f R. The ta b le shows th a t R becomes more stable i f N is closer to the number of in d iv id u a ls . The la rg e r the N the greater the accuracy o f the derived d is t r ib u t io n type, because more nearest neighbor are measured and random e ffe c ts are reduced. Table 11 is an expanded version of Table 10. Instead of R values, the conclusion about the d is trib u tio n pattern fo r each f i e l d and each N is l i s t e d . The l a s t column fo r every f i e l d is the actual d is tr ib u tio n pattern fo r a given population. Table 11 also f i e l d data renders a clumped d is trib u tio n from the density and time of observation. shows that most o f the of in d iv id u a ls , independent Spatial and Temporal E ffe c t on Larval D is trib u tio n Table 12 is the l i s t o f R values of d if f e r e n t observations in 1976 (summarized from Appendix A ). The table shows that the differe n c e o f individual patterns between dates and plots are not s ig n ific a n t. It seems th a t the d iffe re n c e o f d is trib u tio n patterns are due to random fa c to rs . The 1977 data shows a change in individual patterns (Table 11). High density indicates a clumped d is tr ib u tio n and low density indicates a random d is t r ib u t io n . The random characters o f the la te larvae and pupae were probably due to random m o rta lity factors. 84 Table 10. E ffe c t o f N to the Values o f R of Selected Fields 10 Number o f Distance Measurements (N) 20 30 40 50 100 125 .81 .75 .94 .49 .62 .63 .63 333-2 .33 .68 .39 .34 .58 .58 444-1 .49 .60 .80 .50 .64 111-3 .61 .84 .78 .67 555-1 1.16 .78 1.02 .71 Field 5 333-1 150 200 - - - .41 - - - .63 - - - - .69 .68 - - - - .78 .92 .76 .87 .83 .91 Table 11. Field Nearest Neighbor Analysis of Asparagus Field Data (Cass County, 1976 and 1977) Date Density 5 10 20 Number of Distance Measurements (N) 30 40 50 75 100 125 150 200 Data 1976 c c c c c c c c c c - - - - - - - c - - - - - - - - - - - - - - - - - - - - - - - - - - - - C - - - - _ - - - - - - - - - - - - R - - - - - - - - - - - - - - - - - - R R R - - - - - - - - 53 13 22 36 R R R R R RG R R R c c c - - - - - - - - - - - - - - - - - - - - - - c - - - - - - - 7-29-77 266 R R R c c R R c c c c 555-2 8- 5-77 54 R R R R R C - - - - - 555-3 8-12-77 25 R R R - - - - - - - - 555-4 (Pupa) 8-16-77 16 R R - - - - - — - — “ 333-1 444-1 8- 9-76 8- 9-76 110 93 R C R C R R C C 333-2 444-2 111-1 222-1 8-12-76 8-12-76 8-12-76 8-12-76 115 29 14 12 C C C R R C C C C R C - 444-3 444-4 111-2 222-2 8-17-76 8-17-76 8-17-76 8-17-76 25 17 23 7 C C R R R R C 333-3 8-23-76 29 111-3 222-3 333-4 444-5 8-29-76 8-29-76 8-29-76 8-29-76 555-1 R C Data 1977 R = random distribution; C = clumped distribution; RG = regular distribution. 86 Table 12. R Values o f D iffe r e n t Dates o f Observation and Field s/P lots o f Armyworm Larvae in Cass County, 1976 R of the Highest Calculated N Date Field Density 8- 9-76 333-1 444-1 110 93 .75 .58 8-12-76 333-2 444-2 111-1 222-1 115 29 14 12 .51 .93 .45 .58 8-17-76 444-3 444-4 111-2 222-2 25 17 23 7 .54 .68 .92 1.26 8-29-76 111-3 222-3 333-4 444-5 53 13 22 36 .68 1 .33 .78 .72 8-23-76 333-3 29 1 .18 87 Quadrat Count Analysis Spatial an a ly s is , u t i l i z i n g th is method, was based on frequency counts of individuals in the a r b i t r a r i l y chosen sample u n i t , number of samples, and number o f in d iv id u a ls . To understand the e f fe c t of sam­ pling to the d is tr ib u tio n type, the output o f the program w i l l be com­ pared with the output o f the nearest neighbor method. Randomized Sampling E ffe c t Table 13 shows the c o e f f ic ie n t o f v a ria tio n s o f d is trib u tio n s t a t i s t i c s of two data sets. The complete re s u lt o f each run is pre­ sented in Appendix F. Table 13 demonstrates th a t the la rg e r the number o f samples taken, the smaller the v a r ia tio n . According to the nearest neighbor analysis both sets o f data are aggregated, but from the analysis using n = 5, and 10 these data could be random or aggregated. For n = 100, variance, variance/mean, and I Delta have the lowest v a r ia tio n . The e f fe c t of randomization is reduced by using a large number o f samples. Relative Cost Estimates The re s u lt o f the c a lc u la tio n o f the r e la t i v e cost measuring one u n it (Cu) from observations in the asparagus f i e l d (1 9 7 7 ), is shown in Table 14. The number o f 1 sq. f t . samples counted in one hour (NF) is calculated as NF = (60/TS + TM)A where TS is the time needed to count one sample and TM is the average moving tim e, and A is the u n it s ize . 88 Table 13. C o e ffic ie n t of Variations of D is trib u tio n S t a t is t ic s of Armyworm Larvae in Asparagus Fields (Cass County, 1976) S ta t is t ic s and Field 5 10 Number of Samples 30 50 70 100 Variance Field 111-3 Field 333-2 94.92 449.85 52.38 219.79 44.01 93.28 37.11 47.59 45.01 56.72 21 .36 24.66 63.85 83.69 42.38 155.77 45.19 90.31 29.09 41.52 18.81 39.93 8.76 19.84 177.78 32.33 90.30 82.80 52.91 87.63 55.33 32.29 30.58 25.33 14.49 20.87 Variance/Mean Field 111-3 Field 333-2 I Delta Field 111-3 Field 333-2 89 Table 14. R elative Cost Estimates of Asparagus F ie ld (1977) Number of 1 Sq.Ft. Sample Counted in 1 Hour (NF) Relative Time Required to Count One Unit (Cu) Unit Size in Sq. Ft. (A) Time Needed to Count 1 Sample in Minutes (TS) .4 .6 .8 1.0 1.2 1 .08 1.23 1.71 2.38 2.44 18 20 21 20 24 .027 .030 .038 .050 .05 1 .4 1.6 1 .8 2.0 2.2 2.63 2.88 3.26 3.71 3.80 26 28 28 28 30 .053 .057 .065 .071 .073 2.4 2.6 2.8 3.0 3.2 4.02 4.24 4.53 4.90 5.15 32 32 33 33 34 .075 .082 .084 .091 .094 3.4 3.6 2.8 4.0 5.35 5.70 5.85 5.89 35 35 36 37 .097 .103 .105 .108 90 The average moving time (TM) is .55 minutes. The r e l a t i v e time required to count one u n it is not proportional to the un it s iz e . Optimum Sampling Analysis Cost estimates from Table 13 were used fo r calc u la tin g Relative Net Precision (Cochran, 1963). Variance o f sampling units were obtained from outputs o f the program (N = 100). Appendix G presents the results o f RNP calculations fo r the data. For a fixed cost, the sampling unit with a higher RNP gives b e tte r precision than units with low RNP's. Ratings of RNP o f d if f e r e n t fie ld s in 1976 and 1977 are presented in Tables 15 and 16. Only the f i r s t to the f i f t h sampling u n its , with the highest RNP, are included in these tables (see also Figures 22, 23, and 24 ). The re la tio n s h ip between the optimum sample un it size and popula­ tio n density was not c le a r (Tables 15 and 1 6 ), even though there is a trend th a t the smaller sample u n it is fo r the higher density. RNP is dependent on the method o f sampling, u n it s iz e , and the type of d is t r ib u ­ tio n . I t seems th a t the optimum sampling u n it size is la rg e r than 1 sq. f t . , and averages around 2.5 sq. f t . As population density and d is t r ib u ­ tio n (hence variance) is always flu c tu a tin g , not too much stress should be placed on a precise determination o f the optimum size o f the sampling u n it. 91 Table 15. Date RNP Ratings o f Field D is trib u tio n of Armyworm Larvae in Asparagus (1976) Rating o f RNP fo r Sample Units (sq. f t . ) 1 “ 2 3 4 5 Density Field 8 - 9-76 110 93 333-1 444-1 1 .2 1 .2 3.2 4 .0 1.6 3.4 2.8 1.6 2.6 2.6 8-12-76 115 29 14 12 333-2 444-2 111-1 222-1 4.0 1 .2 1 .4 1.4 2.6 3.8 2.2 1.0 2.8 3.2 .8 2.4 2.2 4 .0 2.4 3.8 3.2 2.0 3.8 2.2 3-17-76 25 17 23 7 444-3 444-4 111-2 222-2 .8 3.4 2.0 2.2 1.6 3.0 1.6 3.2 3.4 1 .8 3.0 3.6 1 .8 2.4 3.6 3.8 1.0 2.6 .4 2.8 8-23-76 29 333-3 4.0 3.2 3.6 3.8 2.0 8-29-76 53 13 22 36 111-3 222-3 333-4 444-5 2.6 2.6 3.4 4.0 1 .6 2.8 3.6 2.2 2.2 4 .0 3.8 3.8 2.4 3.0 1 .4 3.4 .8 3.2 2.4 1.2 92 Table 16. RNP Ratings o f Field D is trib u tio n of Armyworm in Asparagus (1977) Ratings o f RNP fo r Sample Units (sq. f t . ) 5 1 2 3 4 Density Field 7-29-77 266 555-1 2.2 3.4 2.0 4 .0 3.8 8- 5-77 54 555-2 2.6 1 .8 2.8 3.6 1 .6 8-12-77 25 555-3 2.8 1.6 2.2 4.0 .6 8-16-77 16 555-4 3.2 3.4 3 .8 4 .0 1.2 Date SO- o 40.0 30.0 NET 10.0 RELRTTVE vo u> 20.0 PRECI SI ON « T 0. 0 I— | I | 0- 5 I I I 1 1 1-0 1 1 I 1 1 1-5 1 1 1— I 1 2. 0 QUADRAT SIZE Figure 22. 1 1 1 1 J~ ' I -I 1I 2. 5 IN SQ. 1 1 3. 0 1 1 I 1 1 3- 5 1 1 1 1 1 4. 0 FT. R elative net precision o f quadrat sizes fo r armyworm la rv a l sampling ( f i e l d 111-3 the density = 5 3 ) . X o RELATIVE NET PRECISION ° w csi- O f— o o a o o o o DAY AFTER EXPOSED TO APANTELES Figure 30. Daily food consumption of unparasitized armyworm larvae and larvae parasitized by Apanteles m il i t a r i s. 114 Compared with Tachinids, Apanteles is more e f fe c tiv e in reducing the amount o f d e f o lia t io n caused by armyworm. I t attacks armyworm in the early in s ta rs , and th is has a large impact on the heavy feeding la te stages. Its effectiveness should be considered and u t i l i z e d in future integrated control s tra te g ie s . E ffe c t o f Apanteles on Host Growth - Table 22 and Figure 30 in d i­ cate that during stadium IV (day 2-day 5) the rate of food consumption of parasitized larvae is greater than unparasitized larvae (although not s t a t i s t i c a l l y s i g n i f i c a n t ) . The parasitized larva has a greater metabolism ra te due to what Slonsky (1978) refers to as an "adaptive in te re s t" o f the p a ra s ite . Parker and Pinnell (1973) also reported th a t the larvae o f P ie r is rapae p arasitized by Apanteles glomeratus consumed s i g n i f i c a n t l y more food than normal larva in the 1 s t, 4 th , and 6th in s ta rs . Slonsky (1978) stated th a t the increased food consumption was caused by: 1) g re a te r duration o f the e n tire la rv a l period, and 2) parasitized la rv a may have fed a t a fa s t e r r a te . This study shows th a t there is no real d iffe re n c e of la rv a l dura­ tion between p a ra s itiz e d and unparasitized armyworm la rv a ; the increased food consumption was probably due to parasitized larvae feeding at a greater rate than unparasitized larvae. This case is supported by the f a c t th a t t o t a l food consumption by para s itize d la rv a has a p o s itiv e c o rre la tio n with the number o f Apanteles individuals inside the armyworm (Figure 3 1 ). The number o f parasites per la rv a l body is calculated as a number o f Apantel es cocoons emerging from each observed larva (see Table 21). This useful information must be considered in the 60.0 80.0 x 40.0 7 = 1 2 . 7 B M .37X R2=. 7 7 4 4 20.0 0.0 FOOD CONSUMPTION (CM2 LEAF) 100.0 115 --------- 1---------- 1---------- 1---------- 1---------- '---------- 1 0.0 to.o 20.0 30.0 n 1---------- '---------- 1 40.0 50-0 NO.RPRNTELES COCOON/RW LRRVR Figure 31. I n i t i a l re la tio n s h ip between number of Apanteles cocoons emerged from armyworm l a r v a , and to ta l food consumption o f p arasitized larva (up to day 6 a f t e r eclo s io n ). “ i 6 0 .0 116 development o f a model of the in te ra c tio n between armyworm, parasites, and host plan t fo r a management program. Field Parasitism Rates 1976 Field Study Two tachinid p arasites, Winthemia r u f o p ic t a , and the pupal para­ s i t e , Archytas a p i c i f e r , were collected from wheat f ie l d s in Cass County by quadrat count sampling. Four sets o f sampling data gives b r i e f information about the density dependent re la tio n s h ip between populations o f armyworm and both parasites (Figure 32). Percentage o f parasitism by Winthemia was highest when the armyworm population reached i t s peak. These parasites must be the m o rta lity fa c to r th a t reduced the armyworm population in the wheat season. I t should be r e it e r a t e d , th a t no army­ worm population was found in the f i e l d a f t e r June 27, 1976, which might be due to the low population of armyworm and readiness of the crop to be harvested. In 1976 Winthemia became the most dominant p a r a s ite , which might have been caused by the following conditions: 1) widespread high popu­ la tio n s of annyworm which could i n v i t e the parasite to move from other a v a ila b le hosts to the armyworm. In th is case armyworm was more s u i t ­ able and a v a ila b le fo r Winthemia, than other hosts such as H e!iothis and other Noctuids. 2) The parasitism was successful because the emergence and occurrence o f Winthemia in the f i e l d was in synchrony with the phenology o f the armyworm. 3) The absence or weakness o f in te rs p e c ific competition especially with Apantel es m i l i t a r i s which attacks arn\yworm in e a r l i e r stages. PRRRSITISM 0.0 10.0 20.0 ( 30.0 PERCENT ) 40.0 60.0 50.0 c_ c z Figure 32. Parasitism of armyworm larvae 0> to a in wheat cn (Cass County, 1976). X ro c_ c •"0.0 25.0 50.0 75.0 100.0 RRMYWORM DENSITY LLL 125.0 150.0 118 Figure 33 represents the to ta l catch o f Winthemia a d u l t s / f l ie s in 3 emergence traps in the same f i e l d . The catches coincided with the development of Winthemia on armyworm larva (Figure 3 2 ). The peak of parasitism was on June 12, and the peak o f f l y emergence was on July 6, 1976. The next generation o f Winthemia, adult females la id t h e ir eggs on other a v a ilab le a lte r n a te hosts, since the 5th or 6th arniyworm instars were not a v a ila b le a t th a t time. I f there were not enough a lte rn a te hosts a v a ila b le in the f i e l d , Winthemia must have experienced a s ig n ific a n t population crash in the following generations. 1977 Field Study Sweep sampling data taken from the wheat f i e l d in Cass County shows a d i f f e r e n t pattern o f parasitism. Three parasites were dominant; two Braconids, Apanteles m i l i t a r i s and Meteorus communis, and one Tachinid, Winthemia r u f o p ic t a . Figure 34 i l l u s t r a t e s the r e la t iv e abundance of the three major parasites and t h e i r host over time. Even though the graph does not show the m ulti-g e n e ra tio n 's r e la tio n s h ip , i t demonstrates the character of in te rs p e c ific competition between the three parasites fo r the same resource. The two Braconids seemed to c o -e x is t even though m o rta lity was density dependent. of the observation time. Apanteles had the highest parasitism during most Meteorus also showed a s ig n ific a n t parasitism which reached 30% on June 1. Winthemia parasitism was low at the beginning, but i t increased s ig n ific a n tly a t the end o f the observation period while the armyworm population and Braconid parasitism was d e c lin ing . The low parasitism o f 28.0 21.0 14.0 7.0 NO.OF FLIES CAUGHT / DAY 35. o o o JUN Figure 33. JUL Number of Winthemia adults caught in emergence traps (Cass County, 1976). AUO 72. r< o 48.0 -o (O CO 36.0 O -C D a: ro 24.0 O —Csl CO NETE0RU8 12.0 PARASITISM (PERCENT) 60.0 at O -C O O o MAY Figure 34. JUN io 20 Parasitism of armyworm larvae in a wheat fie ld (Cass County, 1977) o JUL 121 Winthemia might have been caused by several facto rs: 1) the endemic armyworm population did not a t t r a c t Winthemia females; i . e . , they might have la id t h e i r eggs on more s u ita b le and a v a ila b le host species, 2) Winthemia could not compete successfully with the Braconids which attacked the host e a r l i e r , and 3) Winthemia development and occurrence in the f i e l d did not synchronize with the development o f the armyworm; i . e . , coming too l a t e , the f l i e s had to find a lte rn a te hosts to continue t h e ir development. Bucket Experiment Larval recovery was high f o r the e a rly and middle instars of la rv a e ; 50-60% o f the 1st through 4th instars were recovered a f t e r being exposed f o r 3-4 days. The recovery rate was low fo r the 5th and 6th instars (25%). The remaining larvae moved out of the bucket and were not recovered. Apparently, the plants and shade in the bucket did not give enough protection and fresh food fo r the exposed larvae. Results o f the parasite observations ( in the labo ratory) is pre­ sented in Figure 35. Between June 28 and August 24, a l l recovered larvae were k ille d by Nuclear Polyhedrosis V iru s , and the parasitism during th a t time could not be detected. Figure 35 shows the re la tio n s h ip between the armyworm and its three major para s ite s . Both Braconids ( Apanteles and Meteorus) compete fo r the lim ite d number o f host. Winthemia came l a t e r a f t e r both Braconids stopped t h e i r parasitism o f the armyworm larvae. cannot compete successfully with Apanteles and Meteorus. supports the previous analysis of the sweepnet data. Winthemia This evidence —-• if ^ . ,mir Apante le s m i l i t a r i s Meteorus communis W Winthemia ru fo p ic ta P a r a s it is m 30 Percentage 40 of 50 20 10 June Figure 35. Ju ly August September October Parasitism of armyworm larvae in a wheat fie ld (bucket experiment, Cass County, 1977). 123 I f th is method is used again, more buckets and exposed larvae w i l l be needed to gain a b e tte r in s ig h t. Another method which can assure the f u l l recovery o f the exposed larvae should be investigated to replace the bucket method. Oviposition Pattern o f Winthemia Danks (1975a) stated th a t parasitism by Winthemia may be propor­ t io n a l l y greater where the host is lo c a lly more abundant. Such be­ havioral responses to lo c a lly higher host densities apparently occur in Winthemia ru fo p ic ta attacking H e!iothis spp. w ithin tobacco f ie l d s . Winthemia adults show a marked response to the spatial d is trib u tio n of armyworm la rv a e . Adults would la y more eggs where armyworm larvae are aggregated. To check the behavioral reponse of Winthemia attacking the army­ worm w ith in wheat f i e l d s , Winthemia parasitism data in the wheat f i e l d in Cass County in 1976, was plotted and presented in Figures 36 and 37. Figure 36 displays the trend o f density dependent rela tio n s h ip between the armyworm and Winthemia o v ip o s itio n , but Figure 37 does not indicate th is kind of r e la tio n s h ip . The behavioral response of Winthemia attacking the armyworm w ith in asparagus-crabgrass f ie ld s is represented by the mapped d is tr ib u tio n of arn\yworm larvae in the f i e l d on July 29, 1977 (Figure 3 8 ). This fig u re displays the d is t r ib u t io n pattern o f p arasitized and unparasitized la rv a e , and the respective in s ta rs . I f 1 x 1 sq. f t . is used as a u n it of observation, a l l para s itize d and unparasitized larvae are recorded, the c a lc u la tio n o f Winthemia parasitism of 100 units can be plotted and summarized by Figure 39. The fig u re shows c le a rly th a t there is no 30.0 40.0 M 20.0 « K 10.0 * 0.0 WINTHEMIA PARASITISM (PERCENT) 50.0 124 ------------------ if------------------ if .0 2.0 4.0 k if 6.0 m 1------------------- 1 8.0 10.0 ARMYWORM DENSI TY PER S Q. F T . Figure 36. Relationship between armyworm la rv a l density with Winthemia parasitism in the wheat f i e l d (Cass County, June 19, 1976). 70.0 125 K 50.0 40.0 30.0 20.0 K 0.0 iO.O WINTHEMIR PRRRSITISM (PERCENT) 60.0 m 0.0 , 5.0 ! 10.0 RRMYHORM D E N S I T Y Figure 37. 1 15.0 1------- 20.0 ”1 25.0 PER S Q . F T . Relationship between arrnyworm la rv a l d e n s ity , with Winthemia parasitism in the wheat f i e l d (Cass County, June 12, 1976). 126 D C o o AO •□ oo • □o □o □□ □ ••o o» o□ □□ parasii • i.a r v a c ,'t" INS' I'AR S t II I N S JAR p n p a r a s i t i p .e p larvae O 6th 1NSTAR Q 5th INSTAR A 4th INSTAR T^-Jth INSTAR Figure 38. D is trib u tio n o f p arasitized armyworm larvae by Winthemia and unparasitized larvae in 10 x 10 sq. f t . asparagus f i e l d (Cass County, July 29, 1977). 127 o o -1 2 o UJ * o S C£ UJ Q_ CO g CO £ £ 5 CE 3Z o i _ co 0.0 2.0 4.0 6.0 8.0 i 10.0 RRMYW0RM DENSI TY PER S Q . F T . Figure 39. Relationship between armyworm la rv a l d e n s ity , with Winthernia parasitism in crabgrass-asparagus f i e l d (Cass County, July 29, 1977). 128 re la tio n s h ip between the aggregation o f the individual larvae with the success o f o v ip o s itio n by Winthemia. Apparently Winthemia search t h e i r hosts and successfully lay t h e ir eggs in a random manner. The basic reason o f the d iffe re n c e between Winthemia behavioral response to H e !io th is spp. in tobacco, and to the armyworm in a wheat or crabgrass f i e l d is the a c c e s s ib ility o f the host. The species of He! io th is are common diurnal hosts th a t often feed exposed, and they are e a s ily attached by Winthemia. Therefore, as Danks (1975a,b) rep orted , the parasitism of Winthemia on He!iothis has a trend to be density dependent. The armyworm b a s ic a lly is nocturnal. During the day larvae avoid exposure to sunshine by hiding under dry leaves, stones, de b rie s , between s o il cracks, inside corn whorls, and in other concealed places. This behavior provides good protection from the parasite a tta c k , e s p e c ia lly to Winthemia adults which are active during the day. The asparagus-crabgrass f i e l d is a good example o f the e f fe c t iv e protection of the plants fo r the armyworm larvae. The success o f egg laying is dependent upon many fa c to rs , such as: 1) the amount o f protection a v a ila b le , 2) the movement o f the host, 3) the density o f the host, and 4) the aggregation o f the la rv a e . Even though the d i s t r ib u t io n o f armyworm larvae is clumped, Winthemia p a r a s it ­ ism does not respond to the aggregation. Another method u t i l i z e d to analyze the data in Figure 38 is by grouping the la rv a e according to the parasitism and compare t h e i r index o f dispersion. Table 23 shows the re s u lt of the neighbor analysis to 3 d i f f e r e n t groups o f armyworm larvae in the sample p lo t. 129 Table 23. Nearest Neighbor Index o f Armyworm Larval Groups in Crabgrass Field (Cass County, July 29, 1977) Mean Nearest Neighbor Distance ( r ) R Index C Test A ll larvae .23 .76 6.45 P a ra s itize d larvae .44 .79 3.52 Unparasitized larvae .29 .77 5.33 Group 130 Table 23 indicates th a t the degree of aggregation o f the p a ra s it­ ized larvae is lower than the unparasitized larvae and a ll larvae. The mean distance o f the nearest neighbor of the parasitized larvae is fa r th e r than the unparasitized larvae. This analysis supports the evidence that Winthemia lays eggs randomly among individuals of armyworm larva in the f i e l d . I f the larvae are grouped in to in s ta rs , there is a difference of aggregation degree between instars 4, 5 and 6 (Table 24). The 4th and 5th instars are d is trib u te d randomly while the sixth in s ta r is clumped. This' d ifference might be caused by the higher density o f the sixth in s t a r , or the sixth in s ta r moved fa s te r than the fourth and f i f t h so they found the best places fo r s h e lte r and food. Host Preference Oviposition Rates Table 25 shows the r e s u lt o f the oviposition experiment A and B (Table 4 ) . Three small grains were tested. Experiment A indicates that more eggs were la id on oat seedlings than on wheat. fewer eggs on Downy wheat than on Genesee wheat. The moths la id I t seems that the pubescence character o f Downy leaves might reduce the number of eggs la id . Experiment B indicates a d if f e r e n t s itu a tio n . Fewer eggs were found on oats than on wheat, and moths la id more eggs on Genesee than on Downy. S t a t i s t i c a l l y , the differences were not s ig n ific a n t. The high variance was due to the fa c t t h a t some seedlings did not have eggs deposited upon them. 130a Table 24. Nearest Neighbor Index o f Armyworm Larval Instars in Crabgrass F ie ld (Cass County, July 29, 1977) Group Mean Nearest Neiahbor Distance (f) R Index C Test Sixth in s ta r .31 .74 5.79 F ifth in s ta r .49 .89 1 .89 Fourth in s ta r .75 .81 1 .90 131 Table 25. Number o f Armyworm Eggs Laid on Three Host Plants in a Free Choice Test (x + S .E .) Plant Experiment A Egg Masses Eggs Downy Wheat (many l e a f h a irs ) 1.0+0.0 3.2+ Experiment B_____ Egg Masses Eggs 4. 3 3.4+1.1 1 5 4 . 8 + 56.7 Genesee Wheat (few l e a f h airs) 1.0+2.0 11.2+19.8 2.6+2.1 100.0+67.0 Oats (no le a f h a irs ) 2.8 + 1 . 9 8 1 .7 + 1 0 3 .9 1.6 + 1 . 5 71.4+82.2 132 Table 26 presents the r e s u lt o f the oviposition experiments C and D (Table 4 ) . table Seven small grains and two grasses were tested. The shows a tendency fo r the following conditions: 1) When given a gree choice, the moths showed a preference for small grains over grasses. 2) Oats are less preferred by moths than wheat, barley or rye. 3) Wheat with pubescent leaves reduce the number o f eggs l a i d . 4) Leaf width may be a fa c to r a ffe c tin g ovip o s itio n . Most eggs were la id in young term in a ls , which were ro lle d lo n g itu d in a lly . Requiring a t ig h t place fo r an oviposition s i t e , the moth w i ll fold the blade and secrete a sticky substance a f t e r depositing eggs. This o v i­ position behavior may explain why moths f a ile d to lay eggs on oats; corn leaves are much wider. In experiment D, eggs la id on corn were found between two leaves th a t crossed each other. This argument might apply also for oat leaves, but cannot be applied fo r grasses which have a narrower l e a f than small grains. These conclusions need fu rth e r in v e s tig a tio n . The Developmental Rates Table 27 shows d i f f e r e n t small grains (including corn) do not cause a s ig n if ic a n t d iffere n c e in the developmental time o f la rv a . Larvae develop slower when fed grasses. development (Table 28 ). Plant hosts do not a f fe c t pupal The re la tio n s h ip between grasses as a food source, weight and m o r ta lity o f larvae and pupae, is represented by Table 29. 133 Table 26. Number o f Armyworm Eggs Laid on Small Grains and Grasses in a Free Choice Test (x~+ S .E .) Plant Experiment C Egg Masses Eggs Experiment D Egg Masses Eggs Downy Wheat 3.0 + 2.7 124.0 + 128.2 2.3 + 2.2 37.0 + 1 0 4 . 5 Genesee Wheat 5.3 + 3.2 376.7 + 306.3 5.0 + 2.2 337.2 + 131.8 Oats 3.3 + 1.5 Rye (Secale cereale) Corn (Zea mays) 7.0 1.5 + 1 .3 50.5 + 57.9 2.3 + 1.5 275.3 + 268.9 2.5 + 1.0 79.0 + 79.1 0 0 1 .0 + 1 .7 124.3 + 215.4 1 .3 + 1 .3 134.3 + 114.1 0 0 - - 0 0 Bariey (Hordeum vulgare) 0.3 + 0.6 Timothy (Phleum pratense) 0 Sorghum (Sorghum vulgare) 1.0 + 1 . 7 Brome Grass (Bromus inermis) 96.0 + 2.0 + 3.5 0 44.3 + 76.8 134 Table 27. Average Longevity o f Armyworm Larvae Fed Small Grains and Grasses (x + S .E .) Plants Longevity (Days) Number of Larvae Downy Wheat 24.39 + 1.72 21 Genesee Wheat 23.41 + 1 .38 14 Barley 23.97 + .91 19 Rye 25.15 + 1 .02 24 Corn 25.79 + .95 18 Oats 24.54 + 1.95 11 Timothy 30.33 + .87 4 Brome Grass 34.33 + 2.89 6 135 Table 28. Pupal Longevity from Armyworm Fed Small Grains and Grasses (x + S .E .) Longevity (Days) Number Observed Downy Wheat 12.75 + 1 .58 18 Genesee Wheat 13.95 + 1 .26 13 Bari ey 12.79 + .97 16 Rye 12.65 + 1 .41 19 Corn 12.85 + .91 13 Oats 13.0 + Timothy 11.43 + .98 10 Brome Grass 12.00 + 1 .07 9 Plant 1 .0 8 Table 29. Average Weight and Mortality of Larvae and Pupae of Armyworm Raised on Different Small Grains and Grasses (x + S.E.) Plant Larval Mortali ty Larval Weight (mg) 10 days 15 days {%) Pupa Weight (mg) Pupal Mortality (%) Barley 50.6 + 16.2 418.8 + 60.6 36.7 304.1 + 24.71 10.6 Downy Wheat 43.5 + 2.7 269.6 + 77.9 50.0 269.0 + 38.0 16.7 Genesee Wheat 108.5 + 6.5 307.3 + 114.7 50.0 235.5 + 47.8 15.0 Oats 103.6 + 16.0 234.4 + 66.4 56.7 209.7 + 26.0 15.5 Corn 23.1 6.7 161.1 + 38.9 50.0 297.3 + 9.0 14.3 Rye 53.5 + 12.1 418.8 + 60.7 23.3 262.5 + 56.0 12.9 Timothy 1 3 .8 + 109.6 + 16.5 66.7 226.6 + 34.1 23.5 Brome Grass 13.7 + 61.8 18.4 60.0 167.2 + 25.4 37.5 2.8 161.8 + 137 Table 29 indicates that grasses have a d i f f e r e n t e f fe c t on the armyworm development, namely: 1) slower growth, 2) lower la rv a l and pupal weight, and 3) increased m o rta lity . The ta b le shows also th a t armyworm grow and survive b e tte r on rye and barley. There is no s ig n i­ fic a n t d iffere n c e o f pubescence o f wheat leaves to the growth and sur­ viv a l o f the larvae and pupae. For the following reasons th is e x p e ri­ ment should be duplicated to collaborate the conclusion drawn from the data presented in Table 29. 1. The amount o f food (seedlings) th a t was fed to the larvae was not the same weight. The d iffe re n c e shown in the la rv a l growth and survival might not be caused by the host plant or the q u a lity o f food, but i t might be caused by the quantity o f food consumed. 2. Some larvae were k ille d by the disease (v iru s ) in la te in s ta rs . The m o rta lity due to the disease was d i f f i c u l t to separate from m o rta lity due to the host plants. However, assuming th a t the virus attacked a ll the larvae at the same r a t e , the d iffere n c e of the m o r ta lity of larva which were fed d i f f e r e n t host plants can be assumed as an e f f e c t of the host plants. Food Consumption Rates Due to some technical con straints, only three plants could be tested completely (b a rle y , Downy wheat, and corn). The average to ta l consumption o f one larva on three d if f e r e n t crops is presented in Table 30. 138 Table 30. Average Total Food Consumption of One Armyworm Larva, Reared on Three Plants PI ants Average Total Food Conumpstion (cm2 le a f surface) Corn 293.27 Bari ey 271 .46 Downy Wheat 234.71 139 The stru ctu re o f corn leaves (which are smooth and succulent), might be the reason why the larvae consumed more corn leaves than wheat or b a rle y . The e f f e c t o f l e a f pubescence on consumption by the larva needs fu rth e r in v e s tig a tio n . The average t o t a l consumption of one larva also analyzed with respect to the consumption during la rv a l stadia (Table 31) shows the to ta l consumption o f la rv a during six s ta d ia , and the percentage o f food consumed by each i n s t a r . The percentage of to ta l consumption data show a general character o f la rv a l feeding. The to ta l la rv a l consumption (regardless o f the host type) was highest during the 5th and 6th in s ta r (Table 31). Detailed data of Tables 30 and 31 are presented in Appendix H. Table 32 and Figure 40 represent the d a ily ra te of food consumption of armyworm larvae th a t were fed b a rle y , Downy wheat, and corn. Detailed data about the ra te o f food consumption fo r a l l larvae is presented in Appendix H. Developmental and Survival Rates Armyworm Developmental times o f the immature stages o f armyworm are re a d ily a v a ilab le in papers by Pond (1 9 6 0 ), Guppy (1 9 6 9 ), and Kuo e t a l . (1970) fo r the o r ie n ta l armyworm, Leucania separata Walk. The development o f each immature stage o f the armyworm at constant temperatures from 10 to 31°C is shown in Table 33. Figures 41 and 42 show the ra te o f development fo r each o f the immature stages, calculated Table 31. Instar Average Total Food Consumption of Armyworm Larvae Downy Wheat Surface Area %Total (cm2) Consum. Bariey Surface Area (cm2) %Total Consum. Corn Surface Area (cm2) %Total Consum. I .13 .06 .21 .08 .30 .10 II .26 .11 .23 .08 2.28 .76 III 2.84 1.21 4.06 1.50 3.28 1.09 IV 4.45 1.90 8.84 3.26 15.02 5.04 V 12.49 5.32 34.93 12.86 45.56 15.27 VI 214.54 91.4 223.19 82.22 231.86 77.73 Total 234.71 100.0 271.46 100.0 298.27 100.0 141 Average D aily Rate o f Larval Food Consumption of Armyworm Bari ey______ Consumed In s ta r (cm2) Downy Wheat Consumed Instar (cm2) Corn_______ Consumed In s ta r (cm2) 3 4 5 .06 .19 .07 .13 .21 I I II II III .07 .06 .09 .17 1 .20 I I II II III .15 .13 .54 .62 1 .23 I I II II II 6 7 8 9 10 .75 1.36 1.62 5.51 3.96 III IV IV IV V 1 .64 1.58 1.81 1 .67 4.95 III IV IV IV V 1 .16 .30 1 .36 2.63 3.00 III III III IV IV 11 10.04 13.81 8.78 25.38 29.99 V V VI VI VI 4.59 3.40 6.98 9.06 9.68 V V VI VI VI 3.96 4.56 3.86 15.98 13.12 IV IV V V V 37.63 58.77 44.22 20.13 0 VI VI VI VI Prepupa 17.22 32.30 58.87 61 .40 29.10 VI VI VI VI VI 11.82 18.95 19.71 32.84 49.14 .V VI VI VI VI 0 0 0 Prepupa Pupa Pupa 0 0 0 Prepupa Prepupa Pupa 66.73 43.02 0 VI VI Prepupa 1 2 12 13 14 15 16 17 18 19 20 21 22 23 262.61 245.85 295.32 142 e c OOUMT H M C AT c GC UJ *■ c 0.0 3.0 6.0 15. 0 DAYS Figure 40. FROM HATCH Rate o f armyworm la rv a l consumption (b a rle y , wheat and co rn ). Table 33. Duration (days) of the Imnature Stages of the Armyworm at Constant Temperatures (Guppy, 1969) Stage 10° Eg? 47.0 Larva 168.0 13* 86.6 21 25 29 18 17 18.5 10.4 6.0 4.0 3.3 3.5 76.7 39.9 25.5 18.7 16.3 18.8+ 31 Instar I 23.0 12.3 7.3 4.5 3.3 2.5 2.5 II 18.0 9.3 4.5 2.8 2.0 1.5 1.8 III 20.0 8.0 4.8 3.1 2.1 1.7 2.0 IV 21.0 10.0 5.1 3.2 2.2 2.0 2.5 V 25.0 11.3 6.0 3.8 2.7 2.3 4.0 VI 22.0 10.8 25.5 12.8 8.3 6.5 6.4 2.0 39. Ot 24.8 V II Pupa * 6.0 45.5 Larvae with seven instars. Duration of stage until death of last larvae. 24.0 16.5 11.5 8.8 144 50- RATE OF DEVELOPMENT (in p e rc e n t) 701 30-1 20 - 10 - TEMPERATURE (OC) Figure 41. The r a te o f development o f six larva instars of the armyworm a t d i f f e r e n t temperatures (Guppy, 1969). 145 70h RATE OF DEVELOPMENT (IN PERCENT) 60 - 50- 40 - 30- 20 - 10- 17 21 25 TEMPERATURE (°C ) Figure 42. The ra te o f development of egg and pupa of the armyworm at d if f e r e n t temperatures (Guppy, 1969). 146 as the reciprocal o f the duration in days o f the stage in question, and plotted against the respective temperatures. An approximation of the base temperature (developmental zero) can be made g raph ically by p lo ttin g the percent o f development per day over d i f f e r e n t temperatures, fin d in g the point a t which the regression lin e crosses the X a x is , and d efinin g th a t point as the development zero. Figure 43 presents the application o f th is method in defining base temperatures-for armyworm la rv a l stages. The estimated base temperature for each immature in s ta r of the armyworm is presented in Table 34. There are three main objections to this method: 1) development, in a l l lik e lih o o d , is not a lin e a r process; 2) the developmental zero, in most cases, can be extrapolated f a r beyond the reasonable l i m i t s , and 3) there are probably d i f f e r e n t developmental zeros fo r many of the physiological processes involved. Therefore, i t is b io lo g ic a lly unmeaningful to estab lish an exact threshold (such as 9.47°C fo r eggs) on the assumption th a t no development occurs below th a t temperature. Another approach to estimating the developmental zero, is the standard erro r method. This is accomplished by a r b i t r a r i l y s u b s titu t­ ing d if f e r e n t thresholds and c a lc u la tin g degree-days from each d i f f e r e n t constant temperature (Table 3 3 ). The mean number o f degree-days and standard e rro r was then calculated fo r a l l temperatures at each th re s ­ hold. The point a t which standard e rro r is minimized is the best f i t estimate o f developmental zero fo r th a t set o f data (see Casagrande, 1971 fo r s im ila r use). 147 RATE OF DEVELOPMENT (IN PERCENT) L1V IV LVI 20 - 8 910 TEMPERATURE (°C) Figure 43. Developmental r a te o f the s ix la rv a l instars of the arntyworm (Guppy, 1969). 148 Table 34. Comparison o f Regression and Standard Error Method fo r Developmental Zero o f Armyworm Immature Instars (Guppy, 1969) Regression Method (0°C) Standard Errors Method (0°C) Egg 9.47 8 Larva 8.39 8 In s ta r L I 8.68 8 L II 9.37 8 L III 8.88 8 L IV 8.71 8 L V 8.69 8 L Pupa VI 5.06 9.65 • 8 9 149 Figure 44 shows standard errors th a t re s u lt from the use of d i f ­ fe re n t thresholds in computing degree-day requirements from Table 33. Table 34 is the comparison o f developmental zeros estimated u t i l i z i n g these two methods. Based on the standard e rro r method, 8°C was used as the develop­ mental zero temperature fo r a l l immature instars of the armyworm. Table 35 shows the ovip osition al adu lt development and number of eggs la id a t three d i f f e r e n t temperatures. lay eggs a t 15°C ( 5 9 . 0 ° F ) . The armyworm moth does not The d iffe re n c e between 22.8°C and 25.0°C only e ffe c ts the length o f preoviposition period but i t does not e f f e c t the oviposition period and number o f eggs l a i d . Unfortunately information about the e f fe c t o f a wider range of temperatures on the o v ip o s itio n habit was not obtained due to the f a il u r e o f the armyworm moth to la y eggs inside the "wooden growth chamber". I t seems th a t the v ib ra tio n and noise which came from the fan in the chamber obstructed the oviposition o f the armyworm moths. The developmental zero o f the armyworm adult based on the a v a i l ­ able data using standard e rr o r method is equal to 16°C (61° F ). This fig u re agrees with Pond's (1960) observations which mentioned that mating did not take place a t mean temperatures 4 0 .7 , 5 5 .0 , and 60°F. Minthemia ru fo p icta (Big) The development period o f Winthemia a t various temperatures was reported by Danks (1 9 7 5 a ), and is shown in Table 36. Developmental zeros (D-0) and rates are used fo r determination of to t a l deqree-days accumulation f o r each period of growth. Developmental 150 • EGGS A LARVAE o PUPAE 70 - 60- STANDARD ERROR 50 - 40- 30- 20- 10 - THRESHOLD TEMPERATURE (O C) Figure 44. Estimation o f developmental zero of immature stages o f the armyworm using standard e rro r method (Guppy, 1969). 151 Table 35. Temperature (°C) 15 22.8 25 E ffe c t o f Three Temperatures on Ovipositional Rate (x + S .E .) Preoviposi tion Period (day) 0 0 10.33 + 2.31 5.07 + Oviposition Period (day) .58 Eggs Laid 0 4.33 + 2.31 845.00 + 7 0 0 . 6 4.67 + 3.06 685.67 + 213.6 152 Table 36. Duration o f Development o f Winthemia rufopicta a t Various Constant Temperatures (Danks, 1975a) Instar 18.3°C 21 °C 24°C 26°C 30°C Egg 4.6 3.7 3.3 3.2 2.8 Larva 5.7 4 .6 2.7 4.0 2.7 Prepupa 2.2 2.3 1.5 1 .1 1 .2 - 12.0 10.6 9.8 8.6 16.0 18.7 11.6 10.7 9.3 Pupa Male Female 153 zero estimates are summarized e rro r method. in Table 37 using regression and standard Figure 45 shows the developmental rates and lin e a r regression approximations fo r each in s ta r . Figure 46 shows standard errors th a t re s u lt from the use of d if f e r e n t base temperatures in com­ puting degree-day requirements. Table 34 indicates th a t eggs larvae and pupae have a low threshold temperature and prepupae have the highest. This high base temperature is needed because Winthemia overwinters a prepupa. There is no fu rth e r development u n til s o il temperatures exceed the developmental threshold. Apanteles m i l i t a r i s Walsh Calkins and S u tte r (1976) provide only lim ite d data of develop­ mental rates o f Apanteles inside the armyworm larvae fo r three constant temperatures ( 2 1 .1 , 26.7 and 27°C). Using the standard e rro r method the threshold temperature o f Apanteles larva inside the host is e s t i ­ mated to be 17°C (Figu re 47) which is high fo r an insect. The average rate of development was not s ig n if ic a n t ly d if f e r e n t fo r parasites in the 3rd, 4th and 5th stage o f the host larvae. Related to the high base temperature, Calkins and S u tter (1976) stated th a t th is p a ra s ite seems to develop well a t moderately high temperatures. But in the f i e l d , i t s slow development at lower tempera­ tures probably would prevent i t from becoming a major d e te rre n t fa c to r during the cool spring weather. Ind ividu als spent 6 .4 days as a cocoon a t 27°C (Calkins and S u tte r, 1976), and 7 .2 days a t 21°C (based on data observations a t the Natural Science B u ild in g ). Adult longevity was 6-7 days a t 27°C, and 10 days a t 154 Table 37. Comparison o f Regression and Standard Error Methods for Developmental Zeros o f Winthemia Stages (Danks, 1975a) L ife Stage Egg Regression D-0 - 1 .93°C Standard Error D-0 0°C Larvae 2.28 2 Prepupae 8.14 12 Pupae 2.10 2 ' PKEPUPAE y = y*.04 + 4.18X 60- 50- 155 DEVELOPMENT/DAY 70- ETCS y = 2.18 + 1.13X 30- LARVAE y 20 - MAIE - PUPAE FEMALE io- 10 18 20 22 24 .82 E .39X 26 TEMPERATURE DECREES CENTIGRADE Figure 45. Developmental rate of Winthemia rufopicta l i f e stages. 6 5 ,* PUPAE 4 ,+ EGGS 3 156 STANDARD ERROR ,¥ LARVAE 2 PREPUPAE 1 0 1 1 7 11 13 15 17 TEMPERATURE DEGREES CENTIGRADE Figure 46. Estimation of developmental zero of Winthemia l i f e stages using the standard error method. 701 w so- 5 7 9 11 13 15 17 10 20 21 TURFS!I01D 'IT M ’KRATirRF. (°C ) Fiaure 47. Estimation of developmental zero of Apanteles m ilita ris larvae (Calkins and Sutter, 1976). 158 10°C; the o v e ra ll l i f e cycle ranged from 17-30 days, with the average a t 19 days. From th is data threshold temperatures o f cocoons and adults could be approximated. E ffe c t o f Temperatures on Survival McLaughlin (1962) investigated the e f fe c t o f temperature upon la rv a l m o r ta lity using moderate to high temperatures. Unfortunately, he did not include the f i r s t and second in s ta r in his study. Guppy (1969) reported the survival o f a l l la rv a l instars under two temperature extremes (10° and 31°C ). was constructed. Combining th is data of both papers, Table 38 An average of 96% o f f i r s t and second in s ta r larvae survived when they were reared at 22.97°C. All sixth in s ta r larvae f a i l e d to complete t h e i r development at 35°C (McLaughlin, 1962). Based on the a v a ila b le data, Figure 48 was constructed. Figure 49 shows the e f f e c t o f temperature on eclosion and adu lt emergence. The data was obtained from Pond (1 9 6 0 ), Guppy (1 96 9 ), Kuo e t a l . (1 97 0 ), and observa­ tions a t 22.7°C. For the purpose of population modelling, the e f fe c t of temperature upon survival is expressed as instantaneous survival rate (Fulton, 1978). This is done because the simulation model is continuous as opposed to a d is c r e te , and the assumption was made that temperature dependent m o r ta li­ t ie s operated continuously. This implies th a t: Pt = where Pon eat t = time Pt = Population a t time t PQ = I n i t i a l Population a = Instantaneous survival r a te . Table 38. Survival of Armyworm Larvae at Different Constant Temperatures in °C (McLaughlin, 1962, Guppy, 1969) Instar 22.2° 23.9° 25.6° 29.4° 31° 33.3° 94.74 — I 62.5 _* — — — II 70.0 -- — — -- III 71.43 78.85 — — 80.70 91.67 66.10 IV 46.67 89.45 — — 82.97 93.94 51.05 V 71.43 93.57 95.0 — 79.1 70.97 86.27 20.0 63.10 _ 60.0 60.7 36.36 16.15 VI •k 10° No data available. 100.0 — e o 0 -1 u CD O(D cr> o UJ 0.0 5. 0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 TEMPERATURE IN CELSIUS Figure 48. Survival of armyworm larvae as a function of temperature in °C (McLaughlin, 1962 and Guppy, 1969). 161 100EGGS PUPAE S U R V I V A L ( PERCENTAGE ) 80- 60- 40- 20 - 5 10 15 20 TEM PERATURE Figure 49. 25 30 35 (° C ) Survival o f eggs and pupae as a function o f temperature in °C. 162 There is an in te ra c tio n between the survival and the time spent in the stage. They both seem to be a function o f temperature. This in te ra c tio n can be removed using the instantaneous survival r a te . I f DEL is equal to the time the individual remains in one stage then the instantaneous survival ra te (a) is calculated as: a = 1n(Pt/Po)/DEL Using the data in Tables 34 and 38, the instantaneous survival ra te of armyworm in s ta rs were calculated (Figures 50, 51 and 52). Late Fall Development The r e s u lt o f observations of the development o f armyworm larvae reared in the insectary is presented in Table 39. The ta b le shows th a t the armyworm keep feeding and changing instars under the low temperature and short day length. This observation indicates th a t the armyworm does not go to diapause: but spent the w inter as a hibernating larvae. Supercooling Test Table 40 shows the m o rta lity o f armyworm pupae a f t e r being r e f r i g ­ erated at 4.4°C (4 0 ° F ). The table indicates th a t the armyworm pupae have a low resistance to exposure under low temperatures fo r a long period of time. This observation supports Breeland's (1958) statement th a t the armyworm is less l i k e l y to overwinter as a pupal stage. The supercooling point o f armyworm instars is presented in Table 41. The table shows a d iffe re n c e in supercooling between in s ta rs . The fourth larvae has a supercooling level lower than the f i f t h and sixth la rv a e . The d iffe re n c e might be due to the size o f in d iv id u a ls . 163 o o IxJ f— -J a: > > (V CD => " CO o o z LU h- o Z cr »— o 25 TEMPERATURE Figure 50. ( 35 CELSIUS ) Instantaneous survival rate of eoas and pupae o f the arrnyworm. 0-00 164 pm — — r * - 00” - « > 0 « N N CD -0.10 V \ \ \ -O.IS \ \V \ c \ \ -0.20 \ -0.25 INSTANTENOUS SURVIVAL RATE -0.05 V " " " " i -0.30 o 15 TEMPERATURE Figure 51. T 25 ( T 35 CELSIUS ) Instantaneous survival rate o f 1 s t, 2nd, and 3rd instars of armyworm larvae. 165 CT • « * C W « -.0 0 4 4 X , O LU I— QZ DC CE CO o I > DC ZD CO CO o I CO ZD o z IxJ CD hz 01 - a: hco o CSJ I 15 TEMPERATURE Figure 52. r r 5 25 ( 35 CELSIUS ) Instantaneous survival rate o f 4 th , 5th and 6th instars of armyworm larvae. 166 Table 39. Development o f Armyworm Larvae Before the F i r s t Frost (East Lansing, 1977) In s ta r Date Started Total D.D. Accumulation ( 46°F) Day Length (hr) L I 9- 7-77 47.0 13.0 L II 9 - 9-77 87.7 13.0 L III 9-16-77 174.0 12.5 137.1 12.0 L IV 10- 6-77 L V 11- 2-77 * U n t il the f i r s t f r o s t on 11-11-77. 83.0* 10.25 Table 40. Number o f Pupae Producing Adults A fte r Being Refrigerated a t 40°F R e frig e ra tio n Period Number o f Pupae Number o f Moths Normal Malfunction Dead Pupae 3 months 143 32 28 83 4 months 117 0 2 115 168 Table 41. Supercooling of Armyworm Instars Under Natural and A r t i f i c i a l Preconditioning (°F ) In s ta r 4th larva Natural Preconditioned Mean 10 A r tific ia l Preconditioned 12 11.5 13 5th larva 11 .5 11 10, 13 13 15.5 19, 20 6th larva 12.5 12 19, 20 14, 16 20.0 20, 21 Pupa Mean 15.0 15 13 14 13.0 14.0 S a lt reported (1964) th a t the size of the insect reduces it s supercooling a b ility . The natural preconditioned specimens did not have a lower supercooling p o in t, but in fa c t i t was higher than the a r t i f i c i a l conditioned specimens. pre­ The pupal supercooling point obtained from th is experiment was 13.5°F (-1 0 .2 8 °C ) which is d if f e r e n t from the re s u lt of Roberts e t a l . (1 9 7 2 ). They found the supercooling of the pupae is - 2 4 . 29°C ( - 1 1 . 7 2 ° F ) . This experiment was done using feeding larvae. ably had food p a r tic le s l e f t in the gut. These larvae prob­ These p a rtic le s could i n i t i a t e and speed-up the formation o f ic e -c ry s ta l nuclei and therefore thelarvae would reach the point more quickly. I f the period o f a r t i f i c i a l preconditioning is lengthened by another 2 or 3 days, the supercooling point w i ll e ventually drop even fu r th e r. S alt (1953) using the pale western cutworm, Agrotis orthogana Morr, found th a t the supercooling point of the feeding larvae was averaging -10.3°C (13.46°F) and ranging from -15.4°C to -6 .9 °C . The supercooling points of non-feeding larvae were s ig n if i c a n t l y lower than the feeding la rv a e , averaging -23.6°C ( -1 0 .4 8 ° F ) . S a lt 's data on feeding larvae does not d i f f e r from the resu lts o f th is experiment. I t seems th a t the supercooling points of armyworm in s ta rs are close to the supercooling points of. A g ro tis . Frost M o r ta lity The f i r s t f r o s t o f 1977 was on November 11. On November 14, cups o f larvae were checked, and i t was found th a t a l l exposed larvae were k i l l e d by the f r o s t . I t seems th a t the grass cover over the cup was not enough protection from the freezing temperature. The armyworm larvae 170 must o v e r - w i n t e r under a t h i c k l a y e r o f grass and o th e r concealed s it e s which can p ro v id e them w ith b e t t e r i n s u l a t i o n . 170 must o v e r - w in t e r under a t h i c k l a y e r o f grass and o th e r concealed s i t e s which can p ro v id e them w ith b e t t e r i n s u l a t i o n . CONCLUSIONS This study has been an attempt to i n i t i a t e the investigation of the d is tr ib u tio n and bionomics of the armyworm, Pseudaletia unipuncta (Haw.), which has become increasingly important in Michigan the la s t four years. The study was performed both in the f i e l d and the labora­ tory during 1976 and 1977. At the beginning of the season the population o f the started from two sources. armyworm was The f i r s t group was middle in s ta r of larvae which became ac tiv e from the over-wintering stage. were migrating adults from the southern s ta te s . The second group These two populations produce f iv e or sixth s ig n ific a n t peaks of the armyworm f l i g h t a c t i v i t y . The investigation o f the in te r r e la tio n s h ip between the two populations, i t s host crop and parasites' development are highly essential for the management o f the armyworm. Moths lay eggs on green and dry leaves o f grasses and small grains. Moths have an ovipositional preference fo r small grains over grasses, and i t is apparent th a t oats are less preferred than other small grains. The cause of non-preference in laying eggs may be the width o f leaves. The armyworm larvae are polyphagous, feeding on small and grasses. grains, corn From the laboratory observations i t was found th a t larvae fed grass had: 1) a slower development r a t e , 2) high m o r ta lity , and 3) lower la rv a l and pupal weight gain than those fed small grains or corn. 171 172 This food preference might explain the behavior of the larvae moving from grassy areas to the small grain or corn f i e l d s . The larvae con­ sume more corn l e a f area than barley or wheat. The d is tr ib u tio n pattern of larvae in the f i e l d is dependent upon the a v a i l a b i l i t y and the d is trib u tio n o f food and places to hide during the day; the la rv a l density; and also the age s tru c tu re . The d is t r ib u ­ tio n of larvae in a wheat f i e l d in 1976 was random and the trend seems to be uniform, because the high level o f the population caused the larvae to move away from each other. Due to the low la rv a l density in 1977, the d is tr ib u tio n o f larvae in the wheat was random. The d is tr ib u tio n pattern of second generation larvae in the asparagus and crabgrass f i e l d was highly clumped. The larvae seems to aggregate in the heavy concentration o f crabgrass and avoided asparagus plants as a place to hide. Computer programs have been developed to analyze the d is trib u tio n data by using nearest neighbor and quadrat count method. There is no s ig n ific a n t d iffere n c e o f individual patterns between f i e l d plots and observation dates. The study demonstrates the application o f R elative Net Precision (Cochran, 1963) to obtain the optimum sampling u n it fo r a c ertain d is tr ib u tio n p a tte rn . For the crab­ grass f i e l d the optimum sampling u n it was approximately 2.5 sq. f t . The re la tio n s h ip between the armyworm and i t s parasites Winthemia ru fo p ic ta ( B ig ), Apanteles m i l i t a r i s Walsh, and Meteorus communis (Cress.) has been studied but only during the armyworm f i r s t generation. Winthemia is an activ e p a ra s ite , having a high numerical and functional response, and attacks la te instars o f armyworm la rv a e . Winthemia parasitism in the outbreak year such as in 1976 was high, and i t is 173 highly dependent upon the la rv a l density. Under high density, la te instars are migrating to the bordering f i e l d s , and are more exposed to Winthemia atta c k s . Winthemia parasitism in 1977 was lower than the parasitism of Apanteles and Meteorus. This low parasitism might be due to the movement of Winthemia f l i e s to other more s u ita b le hosts, or to the in te rs p e c ific competition. Apanteles is a h o s t-s p e c ific parasite and i t attacks e a rly instars of armyworm la rv a . Its parasitism was high in 1977 when the armyworm population was low. Even though i t s presence has always been noticed in the f i e l d , th is parasite seems to have a low response to the density o f armyworm. The s p e c ific in te rr e la tio n s h ip between Apanteles and armyworm populations should be a future area of study. Meteorus. p a r a s it­ ism was s ig n ific a n t in 1977, and th is parasite seems to be able to co­ e x is t with Apanteles. Both p a ra s ite s , Winthemia and Apanteles, reduce s i g n if ic a n t ly the food consumption o f armyworm larvae. Winthemia reduces la rv a l food consumption by 50%, and Apanteles by 84%. There seems to be a po sitive re la tio n s h ip between the number o f Apantel es inside the armyworm and the amount of food consumed by the parasitized larvae. By analyzing the development and m o rta lity rates data of Guppy (1969) and McLaughlin (1 9 6 2 ), 46°F was determined to be the temperature base fo r the immature stages o f the armyworm. From these data the equa­ tions fo r the instantaneous ra te of survival o f immature stages were derived. Armyworm moths did not la y eggs a t 15°C. The over-w intering study indicated th a t armyworm over-winters in a hibernation stage rath er than a diapause larvae. The supercooling 174 points f o r a feeding larvae is approximately 15°F, and fo r a precondi­ tioned (24 hours) larvae is approximately 13°F. This study should be expanded to include a longer preconditioning period. I t was apparent th a t the supercooling points o f the armyworm did not d i f f e r from the supercooling point o f other noctuids such as the pale western cutworm ( S a l t , 1953). LITERATURE CITED LITERATURE CITED Anscombe, F. J. 1949. 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Forest S c i. 5: 397-412. APPENDICES APPENDIX A PROGRAM LISTING OF NEAREST NEIGHBOR ANALYSIS 179 180 C C C C C C PROGRAM DISTNC( INPUT, OUTPUT, TAPE 1=65,TAPE2=65) ------------------------------------------------------------------------------------THIS PROGRAM IS DEVELOPED IN A COLLBORATION WITH EMMETT LAMPERT (P H .D . TH E S IS,IN PREP. 1 9 7 9 ), BASED ON NEAREST NEIGHBOR CONCEPT CF CLARK AND EVANS (1 9 5 *0 . THE PROGRAM IS DESIGNED FOR A SET OF DISTRIBUTION DATA IN A 10 X 10 SAMPLE PLOT. --------------------------------------------------------------------------------------INTEGER FIE LD , PLOT,DATE DIMENSION X( 3 0 0 ) ,Y( 3 0 0 ) ,DIST( 3 0 0 ) ,NUMB( 1 5 ) , IVAR(2) 955 1 REWIND 1 PRINT V E N T E R FORMAT FOR X,Y PAIRS" READ 955, ( IV A R ( I) ,1 = 1 , 2) FORMAT(2A10) PRINT*,"ENTER NUMBER OF REPLICATES. " READ*,MCOUNT ICOUNT=0 SUM=0. SUMSQ=0. C ----------------------------------------------------------------------C READ ONE SET OF FIELD DATA C --------------------------------------------------------------------READ (1 ,9 0 0 ) FIELD,PLOT,DATE,M IF (EOF ( 1 ) )3 >*4 900 F O R M A T (T 3 ,2 X ,I1 ,2 X ,I6 ,5 X ,I3 ) *4 DO 10 1 = 1 , N READ(1 , IV A R )X (I) , Y ( I ) 9*45 FORMAT(1X,F10.*4,3X,F10.*4) 10 CONTINUE C ---------------------------------------------------------------------------C SELECT A RANDOM INDIVIDUAL TO START DISTANCE MEASUREMENTS C -------------------------------------------------------------------------2 IND=1+RANF(-1)*N ICOUNT=IC0UNT+1 DO 15 IK = 1 ,1 5 NUMB(IK)=0 15 CONTINUE DO 20 J = 1 , N D T S T (J )= (((X (J )-X (IN D ))* * 2 .)+ ((Y (J )-Y (IN D ))* * 2 .))* * .5 20 CONTINUE WRITE ( 2 ,9 1 5 ) 915 FORMAT(*0*, *40 (1 H - ) ) W RITE(2,9 0 5 ) FIELD,PLOT,DATE,N,ICOUNT uT*TTW?t Qm YT.NU,X(IND) ,Y (IN D ) 901 FORMAT(*0*,*F0R IN D IV ID U A L*, 1 3 , * WHOSE COORDINATES ARE:* + * X = * ,F 5 .2 ,* ,Y = * ,F 5 .2 ,/1 X ,* T H E DISTANCES TO NEIGHBORS* +« ARE 1 -1 0 , 1 1 -2 0 , E T C .*) W R IT E (2 ,9 0 2 )(D IS T (II) ,11=1 ,N ) 902 FO R M A T(10(1X ,F6.3)) SMALL=100. DO *40 K=1,N IF (K .E Q . IND) GO TO *40 OK- 181 C FIND THE NEAREST NEIGHBOR 50 55 MO 90S 904 905 I F ( D IS T (K ) . LT. SMALL)SM ALL=DIST(K) DO 50 L = 1 ,15 L 1 =L IF ( D I3 ( X ) .GE. L - 1 . AND.DIST(X) .L T . L)GO TO 55 CONTINUE NUM3(L 1 ):N'JM3(L 11+1 CONTINUE PRINT*,"NEAREST NEIGHBOR DISTANCE: " , SMALL WRITE (2 ,9 0 S ) f o r MA T (*0*,*NEIGHB0R DISTANCES AND r REQlJENCY COUNTS*,/ * - 1 X ,* 0 - .9 9 9 ,1 -1 .9 9 9 , 2 -2 .9 9 9 , E T C 10 PER RCW * ) W R IT E (2,Q 04)(N ,JM3(L2) ,L 2 = 1 , 15) FORMAT(10 (1 X , 1 6 )) F0RMAT(*0*,*NEAREST NEIGHBOR ANALYSIS FOR CIE L D * ,I4 +* P L O T *I2 , / , 1 X ,*0 N *, 1 7 * , NO. INDIVIDUALS: * 1 3 , * , R ZP 3=*I3) n C CALCULATION OF NEAREST NEIGHBOR STATISTICS 960 SUM:SUM+SM ALL RH0=N/100. SUMS0=3UMS D+3MALL * * 2 . . WRITE(2 , 9.60) RBAR , S2 FORMATCIX,*MEAN NEIGHBOR DISTANCE : * , F 1 0 . 6 , * VARIAN C E=*,F10.6) I F ( ICOUNT. LT .MCO'JNT) GO TO 2 A=c LOAT(MCOUNT) RBAR=SUM/A S2=(SUMSQ-( ( SUM* * 2 . ) / A) ) / ( A -1 1 PRINT*,"RBAR DISTANCE: " , RBAR,"VAR: " ,S 2 C TEST OF SIGNIFICANCE QF THE DISTRIBUTION fro ^ RANDOMNESS 961 3 906 WRITE( 2 ,9 6 1 )RTEST,CTEST F0RMATC1X,*CLARK AND EVANS R: * ,F 1 0 .5 ,* C AND EVANS C : * , F 1 0 . 6 ) R E 3 A R :1 ./(2 .*S Q R T (R H 0)) RTESTrRBAR/REBAR DIFR:RBAR-REBAR DIFR:.ABS(DIFR) RHON:A*RHO STERR:. 26136/SORT(RHON) CTEST=DIFR/STERR P R IN T *," R: " , RTEST," C: ",CTEST GO TO 1 W R IT E (2 ,9 0 5 ) FORMATC* 1 * ) <^TT>D END OK- APPENDIX B PROGRAM LISTING OF QUADRAT COUNT ANALYSIS 182 183 PROGRAM SPACE(INPUT, OUTPUT.TAPE1=65,TAPE2=65, TAPE3=65) ------------------------------------------------------------------------------------------------------------THIS PROGRAM IS WRITTEN IN A COOPERATION WITH EMMETT LAMPERT (PH .D .TH ESIS IN PREP. 1 9 7 9 ) .IT IS CALCULATING INDICES OF DISPERSt 0 m mAMELY,meAN VARIANCE RATIO,NEG.BINOMIAL K INDEX, AND MORIS IT A IN D E X /I DELTA ( SEE E LL IO T T,1977 FOR THE EQUATIONS ) . THE PROGRAM IS DESIGNED FOR A DISTRIBUTION DATA IN 10X10 PLOT. ------------------------------------------------------------------------------------------------------------DIMENSION X( 1 5 0 ) , Y ( 1 5 0 ) , XMEAN(1501 INTEGER FIELD,PLOT,DATE,XMEAN REAL KHAT,IDELTA,MU REWIND 1 MO READ(1 ,1 0 ) FIELD,PLOT,DATE,N 10 F 0 R M A T (I3 ,2 X ,1 1 ,2 X ,I6 ,5 X , 13) CHECK=0. IF (E O F (1 ) ) 7 7 ,2 C ------------------------------------------------------------------------------------------------------------C READ IN X AND Y COORDINATES C ------------------------------------------------------------------------------------------------------------2 DO 11 1 = 1 , N READ ( 1 , M 5 ) X ( I ) , Y ( I ) M5 FORMATOX, F 1 0 .M ,3 X ,F 1 0 .M ) 11 CONTINUE C -----------------------------------------------------------------------------------------------------------------C FIND X MAX AND Y MAX VALUES C C C n C C C r _________________________ ______ ______ ____ ____ ________ _ XMAX=X(1 ) YMAX=Y(1 ) DO 12 J=2, N IF (X (J ).G T .X M A X ) XMAX=X(J) IF (Y (J ).G T .Y M A X ) YMAX=Y(J) 1? 36 210 53 c o nt t n i j f PRINT*,"ENTER THE NUMBER OF SAMPLES TAKEN AND UNIT S IZ E ." READ*,NUMB,SAMPLE I F ( CHECK.NE.O.AND.NUM3.NE.0) W R IT E (2 ,210) NUMB FORMAT( * 0 * , 20X, *NUMBER OF SAMPLES TAKEN EQUALS * , I M , / ' ) DEL1=0. IF (NUMB. EQ. 0)G0 TO 302 SAMPLE=S AMPLE/2. SAMPLE=2.*SAMFLE DX=SAMPLE**.5 DY=DX XX=DX/2. YY=DY/2. ORG=0. 184 X5AR=0. S2=0. T T c ^ T rO . SQFTM=0. IDELTA=0. TVALUE=0. TVALUE2=0. SUM=0. SUMSQrO. IC1=0 IC 2=0 XRANGE=10.-DX YRANGE=10.-DY AREA=XRANGE#YRANGE IF(XRANGE.LT.5 . OR.YRANGE.LT.5 . ) GO TO 36 D047 1 2 = 1 ,N I F ( X ( 1 2 ) .G E .X X .A N D .X C I2 ).L E .( 1 0 . -X X ))Q 0 TO 6 GO TO 4? I F ( Y ( 1 2 ) .G E .Y Y .A N D .Y (I2 ).L E .( 1 0 . - Y Y ) ) 0RG=0RG+1 CONTINUE MU=ORG/AREA 6 47 FINO RANDOM SAMPLE POINTS ) DO 13 K=1, NUMB TOTAL=0. XPT=XRANGE*RANF( - 1 ) Y PT =YRANGE *R ANF( - 1 ' DO 14 1 1 = 1 ,N T C X T 1 'i. o r . XPT. AND. X ( T 1 ) . LE. XPT +DX ) GO TO 5 GO TO 14 IF ( Y (1 1 ) . GE. YPT. AND. Y (T 1) . LE. YPT 4DY ) T0TAL=T0TAL+1. CONTINUE SUM=SUM+TOTAL SUMSQ=SUMSQ+T0TAL**2. XMEAN 0O=T0TAL CONTINUE f f i CALCULATE STATISTICS OF SAMPLES IF(SUM.EQ.O)GO TO 250 XBAR=SUM/NUMB SGFTM=X3AR/SAMPLE S2=(SUMSQ-(SUM*#2. /NUMB)) /(N U M B -1) 185 r ____________________________________________________ __________________ ____ ____ ________ C K HAT CALCULATION TAKEN FROM ELLI0TC1977) P. 55 C ------------------------------------------------------------------------------------------------------------IF ((S U M **2 .-S U M ).E Q .0 )G 0 TO 99 IDELTA=NUMB* ( (SUMSQ-SUM)/(SUM**?. -SIIMI 1 GO TO 91 90 IDELTA= -9 .9 9 9 91 IF ((S 2 -X B A R ).L E .0 . )G0 TO 95 KHAT=X3AR**2. / ( S2-XBAR) GO TO 99 95 K H A T=-9.999 99 TEST=S2ABAR DEX=DEL1/ID E L T A DEL1=IDELTA I F ( IDELTA. NE. - 9 . 9 9 9 )WRITE( 3 ,3 2 0 )SAMPLE, DEX,NUMB 320 F O R M A T (2 X ,2 (F 6 .3 ,5 X ),I3 ) TVALUE=TEST*(NUMB-1) TVALUE2=ir~LTA*(SUM-1)+NUMB-SUM IC D IF IX (S U M ) IC 2=IFIX(SU M SQ ) 250 I F ( CHECK.GT.1) GO TO 301 WRITE( 2 ,2 0 0 ) FIELD,PLOT,DATE,XMAX,YMAX 200 P0RMAT(*1* , / / / / / , MX,*TABLE . SUMMARY OF SAMPLES * +*TAKEN RANDOMLY FROM F IE L D * ,IM ,* P L O T *,1 2 , * . * , / + 1 5 X , * 0 N * , I 6 , * , X M M X = *,F 6 .2 ,*, Y M A X = *,F 6 .2 , * . * ) WRITE( 2 ,2 0 1 ) 201 F O R M A T (*0 *,M X ,7 2 (1 H -)) DR TM T(2,POP) 202 FORMAT( * 0 * , 2X,*SAMPLE COUNT COUNT MEAN*, 19X,*VAR. CM!*,MX, + * I* ,5 X ,* C H I* ,5 X ,* K * ,/,3 X ,* U N IT SUM*,MX,*SUM*,MX,*PER MU * , +*MEAN VAR. MEAN SQ*,3X,*DELTA S Q *,M X ,*V A L U E *,/,3 X ,*S IZ E *, +8X, *SQUARES SQFT*, 19X,*RATT0 T S T *, in v ^ T ^ T in W RITE(2,2 0 1 ) IFCCHECK.LT.1)WRITE(2,210)NUMB CHECK=5. 301 WRITE( 2 , 20M)SAMPLE, I C 1 , IC 2 , SQFTM, MU, X3AR, S2,TEST,TVALUE, +IDELTA, TVALUE2 , KHAT 20M F O R M A T (2 X ,F 5 .2 ,2 X ,lM ,1 X ,l6 f 3 X ,2 ( F M .2 ) ,F 6 .2 ,F 7 .2 ,F 6 .2 , + 1 X ,F 6 .2 ,F 6 .2 , 1 X ,F 6 .2 ,F 7 .2 ) GO TO 53 302 ENDF3LE 3 PRINT*,"ARE YOU DONE?" READ 1 0 5 1 ,ANS 1051 FORMATCA1) IFCANS.EQ.1HY) GO TO 77 GO TO MO 77 WRITEC2,M01) M01 FORMATC*1 *) 1 STOP END APPENDIX C DISTRIBUTION DATA OF LARVAE IN AN ASPARAGUS-CRABGRASS FIELD IN 1976 AND 1977 186 187 TABLE C-l : ARHYtfORM DISTRIBUTION IN FIELD 444 PLOT 5 DATE 82375. NUMBER 1 o 3 4 5 5 7 3 9 10 11 1? 13 1 '4 15 16 17 13 19 20 21 00 23 24 25 26 27 28 29 30 31 32 33 34 35 36 • X COORDINATE . 0773 . 1037 . 2553 1.2880 1.0707 1.8368 2.1527 2.0716 2.9659 2.1447 2.3428 2.4767 2.7558 2.3663 3.3159 3.6154 5.1183 5.4273 6.6033 6 . 1606 6.8447 7 1osou 7.9348 7.7584 7.1304 ^ .3032 3 . 1 7 75 8.6361 8.7756 3.5859 3.7417 3.7926 9.9151 9.6119 9 . 7 390 9.7252 Y COORDINATE 4.2338 4.0512 4.1609 6.227 0 2.0904 4.7322 9.6837 6.7269 8.0711 2.8539 2.1105 1.7193 1.4498 . 3002 . 2000 1.9123 8.0730 6.2168 9.7263 5.5700 6.3602 6.5311 5.7456 5.4273 3.4832 . 2269 4.9004 3.7365 3.6260 3.5653 2.0471 1.9124 3.5192 8 . 3113 8.1035 3.5625 188 "^ABLE C-2 : ARMYm q r m n T < ;tR te u jt TON IN F IE L D 4 4 4 PLOT 4 DATE 8 2 3 7 6 . NUMBER 1 2 3 ’4 5 6 7 3 9 10 11 12 13 14 15 16 17 X COORDI NATE 1.4932 1.3212 2.2038 2.7278 2 . 4Q 55 2.9672 5.0304 5.0193 5.0793 4.7363 4.2155 4.6341 4.5350 4.0747 3.9692 5.069’ 9.7534 Y COORDI NATE 3.0991 5.09 48 4.8297 4.6157 4.4296 .7370 3.9463 7.5124 7.0384 7.3338 3 . 1 3 83 2.4266 1.2175 1.331 3 . 995 1 9.0035 2.9436 189 TABLE C - 3 : ARMYWORM D I S T R I B U T I O N I N F I E L D 44 4 PLOT 3 DATE 3 1 7 7 6 . NUMBER 1 2 3 4 5 5 7 3 9 1o 11 12 13 14 15 16 17 15 19 20 21 22 23 24 25 X COORDI NAT E . 4291 . 1534 . 3495 . 0764 .0614 2.9299 3.3463 3.4714 3.9034 3.9517 4.4315 5.2700 5.6333 5.2522 5 . 271 5 5.2953 5.3351 5.3966 5 . 1654 5 . 1500 3.7071 3.5507 ° . 5 ' 725 9.8415 9.6573 Y COOR D I N A T E 7.6263 7.5029 7.3660 7.0553 6.8198 3.0709 4.0822 3.8963 3.3337 2.9263 3.3610 9.2605 3.7632 3.7140 6.5649 6.3537 6.3163 6 . 1672 6.2172 5.9315 7.0146 4.8465 6.8328 6.6953 4.8203 TABLE C-4: ARMYWORM DISTRIBUTION IN T7TE L r' 4 11 DL O T "> HATE 31276. NUMBER 1 2 3 4 5 5 7 s 9 10 11 12 13 14 15 16 17 13 19 20 21 22 23 24 25 26 27 23 29 X CDORDT NA'T,E . 3458 . 2725 . 2695 .8514 . 5167 . 5031 1.4494 1.7066 1.3452 1.7597 1.9497 1.9359 1.8253 1.2156 2.4666 2.2083 2 . 2q65 3.4299 4.8415 4.6545 M^ 3^1(0 4!5793 5.7046 6.3279 ".5005 7.4347 7.2901 9.4593 5.6704 Y COORDI NATE 9.6733 7.3272 6.5685 6.7331 5.5951 6.3960 9. 1983 9.249 3 9 . 12 36 3.9392 3.9525 3.7161 6.7006 2 . 1827 9.6540 9.3513 8.9045 2.3230 3.9047 3.7421 2 . 4B90 1.0173 5.0433 7.6932 7 . 7544 7.6355 7.2378 6.4525 3.8466 191 TABLE C-5: ARMYWORM DISTRIBUTION IN FIELD 444 PLOT 1 DATE 30975. NUMBER 1 2 3 4 5 5 7 3 0 10 11 17 13 14 15 15 17 13 19 20 21 7° 23 74 25 75 27 23 29 30 31 32 33 34 35 35 37 38 39 40 X C OORDI NA T E .2314 . 4339 .5957 . 3457 . 1094 . 7374 . 277 1 . 5391 .2355 .7535 .5353 .7952 .7945 . 4659 .7231 . 3540 . 2355 1.3300 1.2205 1.4555 1.5946 o # qpc>o 2.9230 2.2305 2.6463 7 . 55' 7 7 2.3157 3.2374 3.5439 3.3503 3.1397 3.3263 3.4971 3.6667 3.3233 3.6039 3.6850 3.3698 3.3092 3.3854 Y COORDI NA T E 9.5712 9.3569 9.3190 9. 2182 9.1303 9.0794 3.9731 8.0155 3.7137 3.6003 8.5493 3.4353 8.2350 3.2850 3.1967 7.5153 4.7239 7 . 8639 7.6671 7.5652 6.6204 8.8893 8.7763 3.7516 3.6381 8.435 3 8.3607 9.7856 9.7225 9.5839 9.4451 3.7254 8.5372 3.4615 8.3935 6.6951 6.4555 6.3934 5.6116 5.3846 TABLE NUMBER 41 42 UR '4 4 45 45 47 48 49 50 51 52 58 54 55 58 57 53 59 50 51 5? 58 54 65 55 67 63 89 79 71 77 73 74 75 76 77 73 79 C-5: CONTINUED. X COORDI NATE 8.4601 3.7393 3.6794 3.3733 4.3756 4.5757 4.5418 4.1872 4 . 4 7 46 4.6710 4 . 1577 4.4939 4 . 2837 4.4573 4.5097 4.3124 4.4930 4.435 4 4.5580 4.4493 4.480 3 4.3563 4.5514 4.7334 4.4574 5.5054 5.3467 5.389 8 5.2307 5.4657 6.921 1 6.3642 6.6379 7.3633 7.7023 7.6031 7.7260 7.6463 7.3445 Y COORDI NATE 3.7579 2.6936 2.5599 2.3950 9.8235 9.6974 9.4199 9.3569 9.2536 9.2434 9.0415 7.8310 7.7306 7.6671 7.6166 7.5410 6.4943 5.5233 4.7163 4.3506 3.5561 1.7276 1.5889 1.450? 1.3745 8.8272 3 . 6 B3 E 7.8058 7.6293 7.5410 1.3493 .7314 . 5927 9.7730 9.6091 9.3695 9.3695 1.3159 1.7402 193 TABLE C- 5: CONTI NUED. NUMBER X COORDI NATE so 31 32 33 34 35 36 37 33 39 90 91 92 93 7.5775 3.4456 8.5615 8.3352 3.7994 9.4976 9.7055 9.3371 9.5211 9.7111 9.6100 9.255 4 9.3011 9.4155 Y COORDI NATE 1.4628 9.3443 2.8121 2.6603 1.7402 9.5339 9.4073 5.7125 5.5738 3.6943 2.7995 2.7364 . 8449 . 504 4 194 TABLE C- 6 : \ p m Y m o p m n T ^ T R T R U T T O N I N F I E L D 3 3 3 P L OT 4 DATE 8 2 3 7 6 . N' J' I BER 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 16 17 13 19 2D 21 22 X COORDTN ATE . 5231 . 6724 .0961 . 0290 . 9 1 14 .1514 . 2642 . 1207 1 . 1157 1.3540 2.2101 2.6039 2.6631 2.8797 6.3400 6.3469 6.2793 6.0277 7.3070 o• a 3.3532 9.2117 oq o Y COORDI NA T E 3.7704 3.4066 7.6992 7.4997 7.1945 3.4237 2.2977 2.1614 4.2652 1.3713 7. 9307 2.4647 . 3392 . 6373 9.5152 5 . 5 9 45 3.5826 3 . 047 3 9.7735 3.1778 7 .6644 3.4059 195 TABLE C - 7 : ARMYWORM D I S T R I B U T I O N I N F I E L D 3 3 3 PLOT 3 DATE 3 2 3 7 6 . NUMBER 1 ? 3 4 5 6 7 3 9 10 11 12 17 1 '4 15 16 17 13 19 20 21 22 27 24 25 25 27 23 29 X COORDI NATE . 1701 . 4497 .5435 . 9974 1.3949 1.431 5 1.4509 2.441 9 2.4192 3 . 4597 3.931 1 4 .4 7 47 5.6345 7.4832 6.3866 5.9549 6.3581 5.6637 6.4683 6.9997 6.5136 7.5151 •7 t *47*71 Y COORDI NAT E 9.0832 3.8434 3.4922 9.4995 3.5072 3. 1956 2.6989 6.3367 . 3703 3.5675 5.6589 1.2816 5.6214 3.8475 5.1920 4.3552 3.6600 3.4652 3•2071 2.4673 0 7 6 ’’ 1.4633 1.2431 . 7 !6966 . 41 6R 3.5249 3.7859 3.5067 8.4774 3.7642 8.6300 7 . 9754 6.9062 6.5443 2.0112 196 TABLE C-8: ARMYWORM DISTRIBUTION IN FIELD 333 PLOT 2 DATE 81276. NUMBER X C O O R D " 1;'! 1 2 3 4 5 5 7 8 9 10 11 12 18 14 15 16 17 18 19 20 21 22 93 24 25 . 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 . 1835 .1314 . 3238 .2571 . 8854 . 3846 . 8Q7 5 . 2559 .5761 .7549 . 9473 . 6262 . 9031 .7410 . 9323 . 6246 . 6875 .7641 .5839 .7506 . 9042 . 7623 . 5831 . 6599 . 9033 . 7492 . 5567 .6716 .9026 . 8330 .9531 1.2633 1.5072 1.6214 1.1930 1.4028 1.6073 1 .221 3 1.3603 1.6173 Y COORDI NAT E 2.6276 2.5031 2.5156 2.1046 2.1295 2.0050 2.0050 1.9173 1.8680 1.7634 1.7303 1.6936 1.6637 1.5940 1.5193 1.4446 1.2453 1. 1955 1.0959 1.0959 1.0535 .9963 . 95 89 .9465 .9215 .8717 . 3468 .7721 . 8095 .7223 . 6349 5.0809 5.1183 4.9440 4.3941 4.3443 4.7323 4.5205 4.2092 4.2964 197 TABLE NUMBER 41 42 43 44 45 46 47 43 49 50 51 52 53 54 55 56 57 53 59 50 51 62 63 54 55 55 67 53 69 70 71 7? 73 74 75 76 77 73 79 C-8: CONTINUED. X COORDI NAT E .9377 1.0640 1.0363 1.2739 1.0451 1.7241 1.5569 1.0570 . 992 4 1 031 9 2.6097 3.3643 4.2393 4.2503 4.1591 4.4027 4.5553 4.2459 4.2332 5.1013 5.3961 5.7927 6 .0095 5.5222 5.6110 5 ^7005 5!5456 7.2330 7.3910 7.3230 7.563 4 7.9937 7.7757 3.0693 7.9415 3.1200 7.9146 7.9342 7.3443 Y COORDI NA T E 2.0797 1.9301 1.6563 1.5063 1.0336 . 9539 . 3342 . 3966 . 3095 .7721 5 . 1059 . 9091 7.4097 5.1203 4.3194 4.3194 4.8553 4.5205 . 1868 7.8329 7.7953 7.6588 7 .4844 7 .4595 7.3101 7.2727 7,1103 9. 1233 8.9913 3.381 1 3.2690 5.0137 5.0062 4 . 89 41 4.8317 4.7198 4.6324 3.5367 3.7111 TA3LE NUMBER 80 81 82 83 34 35 35 37 33 39 90 91 97 93 94 95 95 97 93 90 1 00 101 1 02 1 03 1 04 1 05 1 05 1 07 103 1 09 110 111 112 113 1 14 1 15 C-8: C ON TI N U E D . X COORDI NAT E 7.7913 3.7350 3.5449 3 . 271 5 3.5015 3.9231 3.6652 3.4050 3.1613 3.1607 3.2355 3.2229 3.991R 3.4422 8.1296 3.1405 3.911° 3.7051 3.8031 0 .3539 9.1909 9.5833 9 .7166 10.0114 10.1065 0.555 4 9.4106 9.3070 9.4356 9.4473 9.5875 9.3433 9.4347 9.7150 9.5324 9.2625 Y COORDI NA T E 3.4371 8 .3169 3.6052 8 .3635 3 .2316 3.0075 7.7709 7.3350 5.1631 4.9933 4 . 8 9 41 4.7695 4 . 6 4 51 2.9753 2.2042 1 .9303 . 2491 .1494 . 0623 9.2030 7.73 33 7.7709 7.7953 7 t q o n 4!6202 4.1963 4.0508 3.8354 3.9103 3.7733 3.6433 3.6364 3.6115 3.5367 2 .3518 2.9514 199 TABLE C-9: ARMYWORM DISTRIBUTION IN FIELD 333 PLOT 1 DATE 80976. NUMBER 1 ? 3 4 6 6 7 3 Q 10 11 12 13 14 15 16 17 18 1Q 20 21 22 7^ 24 ?5 26 27 23 29 30 31 32 33 34 33 36 37 33 39 40 X COORDI NATE . 3133 .5743 . 3265 . 37 37 . 6709 1.4495 1.1934 1.6253 1.4837 2.3048 2.1968 2.4312 2.5374 2.7041 2.4946 2.1686 2.3367 2.54 43 2.347 3 2.3070 2.2793 2.5132 ? . 6 16 2.* 4 3 3 5 2.1863 2.3155 2 . ° 1 35 2.5252 2.6012 2.3156 2 . 2 7 33 2.6247 2.3894 2.6223 2.1302 2.3552 2.7293 2.8240 4.2364 4.1293 Y COORDI NATE 8.7939 1.7395 1.6271 1. 1092 . 9436 9.4497 4.6733 4.4994 3.7551 9.2434 3.7894 8.8640 3.901 1 3.3752 3.6369 3.5497 3.4604 3 . 4467 3.25 33 3.0565 7.3673 7.3737 7.3024 7.6897 7.6910 7 . 5641 6.4732 6 . 3333 6.1359 6.1499 5.8345 5.8580 5.6950 5.6559 5.5319 4.7861 3 . 1302 2.0691 7.4281 7 . 1332 TABLE NUMBER C-9: CONTINUED. X COORDI NAT E 31 3? 33 34 35 35 37 33 39 90 91 99 93 94 95 95 97 93 99 100 101 3.4451 3.7172 3.4177 3.2231 3.5350 3. 3 9 0 7 3.2343 3.5753 3 .4553 3.3349 3.0993 3.3592 5.4749 7.3434 7.4595 7.5337 7.2905 7.2235 rr. 4 7 0 2 7.3335 7.3955 3.2523 1 9* 3 Q , l( 7 O fl 1 03 10 4 105 105 10 7 103 109 11 0 3! 7 0 5 3 9.7705 9.5732 ' i. 31 70 9.32 42 9.5303 9.4934 9.3954 BO Y COORDI NA T E 1 .8134 1 .7439 1.5520 1 .6333 1.5981 1 .5435 1.4352 1.4203 1 . 3 4 51 1.1195 .981 8 .6143 5.5254 9.2053 3.8007 5.401 3 5 . 2 5 11 5 . 1403 4.5335 4.3821 .7531 9.2335 .5280 . 4353 7.6274 7.3330 4.9732 4.9504 4.3380 4.3258 .7480 201 TABLE N'J'IBE? M1 42 43 44 45 45 47 43 42 52 51 52 53 54 55 55 57 53 59 50 51 52 53 54 55 55 57 53 59 70 71 72 73 74 ^5 75 77 78 79 C-9: CONTINUED. X COORDI NATE 4.4 2 92 4 . 3 4 35 4 . 1937 4 . 3 7 55 4.3345 4.1719 4.341 3 4.2215 4 . 337 0 4.3305 4.3423 4.237 3 4.5099 4.4327 4.2513 4.1053 3.0313 3.5539 3.1173 3 . 4 7 92 3.0072 3.4353 3. 1491 OeO'l ” 1 3.2330 3.4530 3. 1710 3.3732 3.3557 3.4177 3.5194 3.2453 3.1430 3.3359 3.3532 3.2135 3 . 3 7 49 3.5147 3. 1853 Y COORDI NATE 7.2125 5.3570 5.1404 5.7102 5.3595 4.5254 4.7332 4.3725 4.2079 3.5009 1.9351 1.3220 1.8080 1.5593 1.5573 1.595 4 .9. 2145 3.7441 3.571 1 3.4294 7.939 4 7 . 937? 7.9250 7 . 7 1 19 7.5099 7.5204 7.3830 7.3133 4.8442 4.5156 4.2752 4.2397 3.4184 2.6599 2.2553 2.0671 1.9501 1.9009 1.8652 202 TABLE C-10: ARMYWORM DISTRIBUTION IN FIELD 222 PLOT 2 DATE 31776. NUMBER 1 2 3 4 5 5 7 X COORDI NATE 2.8933 3. 1922 3.7377 3.531 2 3.6722 9.5553 9.3441 Y COORDI NATE 7.4643 3.4473 6 .3917 6.2423 6 .0930 4.9451 3.4512 TABLE C - l l : ARMYWORM D I S T R I B U T I O N I N F I E L D 2 2 2 PLOT 3 DATE 32 9 7 5 . NUMBER 1 o 3 4 5 5 7 3 9 10 11 12 13 X COORDI NATE . 3033 . 6670 1.7445 2.7737 3.1711 5.3752 6.1057 6.1177 7.3107 7.4006 7.4500 8.9434 3.5414 Y COORDI NATE 3 . 1 3 39 2 . 1669 3.3533 2 . 1831 .4134 5.7482 9.0103 5.9672 5.9273 5.0356 4.8162 9.2961 2.8942 203 TABLE C-12: ARMYWORM DISTRIBUTION IN FIELD 111 PLOT 1 DATE 81276. NUMBER 1 2 8 4 5 6 7 8 Q 10 11 1? 13 1u X COORDI NATE . . . . 6097 6590 1686 8087 . 9490 .5868 . 2260 . 5097 1.6475 2.6225 '4 . 0 8 7 7 8.7292 3.8420 8.8496 Y COORDI NATE 7.4752 6 .6924 5.6513 5.2283 4.2472 3.5747 3.0299 2.481 4 5.5999 5 . 4714 7.6694 7.5094 6 .6915 4.4157 TABLE C- 13: ARMYWORM DI S T R I B U T I O N I N e' TELD 2 2 2 PLOT 1 DATE 8 1 2 7 6 . NUM3ER 1 2 3 4 5 5 7 8 9 10 11 12 X COORDI NATE 1.8103 1.8517 2.2288 2.5432 2.7573 5.2123 5.0990 5.0207 5.3531 9.7964 9.8456 9.6663 Y COORDI NATE 5.5624 4.3005 5.2948 5.8797 4.4043 5.6034 3.7443 2.6215 2.3934 9.0732 7.9291 5.9035 204 T ABL E C -14: ARMYWORM D I S T R I B U T I O N I N F I E L D 111 PLOT 2 DATE 3 1 7 7 6 . NUMBER 1 2 3 4 5 6 '■7 3 9 10 11 12 13 14 15 16 1” 13 19 20 21 22 2? X COORDI NATE .3621 .5497 . 931 9 1.1751 2.07 23 2.636? 2.4165 2.9322 2 .6063 2.7733 3.1303 3 . 2507 3.2596 3.4515 3.567 4 3 . 4377 6 .4156 7 .177 1 3 . 7 2 39 9.9995 9.9349 9.9930 9.9330 Y COORDI NAT E 9.3022 6.5760 1.9530 1.3413 3.4672 5.6360 5.1669 5.4141 2.521.6 2.4475 9.5056 9.5426 9.4190 3.4549 3.30 66 7.6257 3.4920 Q . 44 1 u 9.7523 9.6292 3.3139 4.5365 1 .9 0 3 6 205 TABLE C-15: ARMYWORM DISTRIBUTION IN FIELD 111 PLOT 3 DATE 82976. NUMBER 1 2 3 4 5 8 7 R 9 10 11 17 13 14 15 15 17 18 19 20 21 22 23 24 25 26 27 28 29 3D 31 32 33 34 35 36 37 33 29 40 X COORDI NATE . 1324 . 2362 . 6334 .9775 . 2739 . 3093 . 49^5 .4111 1.4404 1.4233 1.5409 1.541" 1 . 6 4 47 1.5452 2.9323 2.3123 2.3633 2 .8 3 2 2 2.8759 2 . 3 6 42 2.4015 2.3273 3.0334 4.0036 3.2970 3 . 1396 3.4666 4 .9496 5.7Q83 5 . 1927 6 .3 6 2 2 6.8127 6.3635 6 . 7 9 42 5.6696 5.3325 5.9709 5.7901 6.3°"3 7.0379 Y COORDI NATE 3.0651 7 . 1215 3.3120 2.9549 2.3347 .9547 .3154 .5233 9.6957 9.5973 9 .6 0 9 2 9.4746 8.6293 3.4709 8.9255 7.5314 7.4203 5.6952 4.0425 3.3345 3.7400 3.4953 7.4631 7.0453 5.2267 3.3444 3.4017 1.7507 9.0517 . 3413 8 .8639 3.3729 3.5212 7 . 1472 7 .0 0 1 2 5.9629 6.7542 4.3951 4.4421 5.5664 206 T43LE NUMBER 41 42 43 44 45 45 47 43 49 50 51 5? 53 C-15: CONTINUED. X COORDINATE 7.0510 7.200? 7.4674 7.6051 7.5055 7.6632 7.5334 7 . 3730 7.1320 3.6444 9.2544 o ^ 1o o 0 . 17?6 Y COORDINATE 5.407? 5.0333 4.5106 4.5095 4.3757 4 3523 3 6166 1.3271 .5229 1 . 0331 5.2442 4.7771 . ?7 ?? 207 TABLE C-l 5: ARMYWORM DISTRIBUTION IN FIELD 555 PLOT 1 DATE 72977. NUMBER 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 15 17 13 19 20 21 22 23 24 25 25 27 23 29 30 31 32 33 34 35 36 37 33 39 40 X COORDI NATE . 397 0 . 5455 . 8505 .7793 . 5099 . 9965 . 8350 . 8403 . 6301 - 3969 . 2434 1 . 5990 1.7990 1 . 1630 1.2970 1.8450 1.5580 1.3370 1.2230 1.8350 1.8320 1.8310 1.1320 1.3920 1.7950 1.1630 1.8430 1.9400 1.7770 1.6140 1.8000 1.7620 1.7980 1.1220 1.1610 1.1840 1.1710 1.8160 1.2810 1.1560 Y COORDI NATE 2.6010 2 . 5 Ji 9 0 4.0990 4.7140 5.3320 5.9800 6.0470 7.1240 7.1250 3.0520 9.1140 10.4700 10.2900 9.5350 9.5220 9.7030 9.3330 3.0550 7.7630 7.6830 7.1700 6.9650 5.3790 5.7490 5.1450 4.7250 4.4010 3.6440 3. 1200 3.0810 2.9910 2.6700 1 .4170 1.8270 1.3910 1.2330 1.3880 .9524 .7633 208 T’ABLE C-15: CONTINUED. NUMBER 41 42 43 44 45 45 47 43 49 50 51 52 53 54 55 55 57 53 ' 59 50 51 52 63 64 65 65 67 63 59 70 71 72 73 74 75 76 77 73 79 X COORDI NAT E 1.8490 2.1220 2.7350 2.6530 2.4550 2 . 0 8 40 2.4330 2.3340 2.3350 2.9120 2.3040 2.4230 2.2590 2.1340 2.2490 2.6950 2.8440 ’ 2.8550 2.8010 2.3260 2.4770 2.2420 2.4330 o m5 0 '40 2 . 7760 2.7540 2.7810 2.9060 2.7330 2.2410 2.1300 2.3310 2.7360 3. 1710 3.8520 3.3500 3.8230 3.7450 3.9310 Y COnRDTMATE .5931 .6430 1.9600 1.3450 3.0900 3.0020 3.4620 3.4500 3.6540 5.0110 5.7930 5.3340 5.7700 5.5650 6.1420 5.2630 5.2670 5.0880 7.5370 7.6730 7.1410 7.32 20 3.3590 3.3710 7 . 58R0 3.0760 8.5750 3.7290 3.8450 9.5910 9.7070 10.3900 9.5630 9.7790 9.6470 6.6600 6.2880 5.5950 5.5820 TABLE NUMBER SO 31 32 33 34 35 35 37 33 30 90 91 92 93 9 ’4 95 95 97 93 09 100 101 1 02 1 OR 1 04 1 05 1 05 1 07 103 1 09 1 10 111 1 12 113 1 14 1 15 1 16 117 1 13 C -15: CONTINUED. X COORDINATE R . 3400 R . 4540 3.1430 R . 4320 R. 6 4 0 0 3.5040 3.3550 3.2040 3.4770 3.4750 3.6370 3.3540 3.3830 3.3260 R. 3 2 4 0 3.3720 3.1390 R . 6100 3. 138 0 3.5950 3.7450 3.1730 4 . 2 0 30 4.4310 4.3940 4.2250 " . 0 9 00 4.6890 4.7630 4.6110 4.8250 4.4940 4.1730 4. 1370 4.1390 4.1020 4.8970 4.9420 5.0120 Y COORDINATE 4 . 7EOO 4.3230 5.0090 4.8410 4.4300 4.3410 4.3160 3.9960 3.9320 3.3280 3.7510 2.6080 1.8390 1.8010 1.4420 1.1720 . 7531 . 7379 . 5224 . 4944 . 4630 . 2145 . 4734 1 . 4R9 0 1.5540 2.4730 2.6460 3. 4 1 ? n 3.5010 2.6690 3.7440 4. 1820 4.4660 4.6070 4.9790 5. 1460 5.4240 4.6160 6. 1230 210 TABLE C-15: CONTINUED. NUMBER X COORDINATE 1 19 1 20 121 1 22 1 2R 1 24 1 25 1 26 1 27 1 23 1 29 1 30 131 1 32 1 33 1 34 1 35 1 36 1 37 1 38 1 39 14 0 141 14 2 143 1 44 1 45 1 46 1 47 143 1 49 1 50 151 1 52 153 154 155 156 157 4 . 4200 4.1340 5 . 07?n 4 . 1490 4.2490 4.9320 4.26 40 4.7330 4.359 0 4 . 1 370 4 . 1330 4.3940 5.3840 5.5710 5.3430 5.8310 5.1850 5.3950 5.2330 5.4570 5.3540 5.1200 5.2130 5.9110 5.8730 5.7030 5.8130 5.7260 5.4940 5 . ' 7 ’ 5 r» 5.8960 5.8460 5 . 4600 5.6320 5.2300 5.3790 6.3950 6.8700 6.1030 Y COORDINATE 6.7030 6.6200 5.17 q0 7.1450 7.3120 7.4380 10.1700 9.7830 9.3330 9.6200 9.8760 9.7700 9.6490 8.9460 3.9210 6.4330 5.0630 5.9930 5.3700 5.8320 5.1010 5.4220 5.1910 5.0720 4.8420 4.0430 3.7520 2.7140 3.3130 2.0600 1.9950 1.8420 1.4850 1.3430 . 2168 . 1904 . 1082 . 9 391 1.2510 211 TABLE C-l 5: CONTINUED. NUMBER 158 1 59 1 50 151 1 52 153 1 54 1 55 1 55 1 57 1 58 1 59 1 70 171 1 72 1 73 1 74. 175 175 1 77 1 78 1 79 1 80 1 81 1 82 1 83 1 84 1 85 186 1 87 188 1 89 190 191 1 92 193 1 94 195 196 X COORDINATE 5.1600 5.5050 6.6420 5.7570 6.8820 5 . 81 00 6 . 1590 5.6080 5.7240 6.8240 6.8880 6.6900 6.6650 6.3950 7.4980 7.4220 . 7.1960 7.2080 7.3510 7.1510 7.1700 7 . 1380 7.4970 7 . 1550 7.1630 7 . 1550 8.2540 8.8880 8.8400 8.6900 8.3960 8.8520 3.9150 8.8430 8.8540 8.6240 3.6120 8.4810 3.5480 Y COORDINATE 2.3270 5.0950 5.0940 5.7860 5.9730 6.4780 7.5580 3.0690 9.1530 9.3110 9.5190 9.6200 9.6530 1 0 . pnno 10.2100 9.9880 9 . 3 7 30 9.2070 3.3960 7.6940 4.0150 2.5270 2.5510 1.1310 . 2325 .5274 .2525 . 6724 .8906 .7503 1.4310 3.3010 3.5950 4.0570 3.8520 4.8790 5.0710 5.1230 7.0590 212 TABLE C-15: CONTINUED. NUMBER 197 193 199 200 201 202 203 204 205 205 207 203 209 210 21 1 2 12 213 214 215 216 217 213 2 1Q 220 221 222 223 224 225 226 227 223 229 230 231 232 233 234 235 X COORDINATE 3.2340 3.7430 3.6370 B . 2170 9.2340 9.4310 9.5300 9.1050 9.3320 9.6150 9.0730 9.3330 9.6990 9.3500 9.5350 9.7710 9.7420 9.5600 9.3330 9.3470 9.3030 9.2530 0.5300 9.5410 9.1440 9.5530 9.6140 9 . 57 50 9.4270 9.2790 9.1250 9.2410 9.3400 9.6340 9.6300 9.1260 9. 1990 9.4590 9. 1710 Y COORDINATE 8.3630 9.9550 10.1700 10.3200 10.3500 10.3400 10.1700 10.0000 10.1300 9.7710 9.0050 9.0290 9. 1940 3.3490 3.8740 3.3990 7.9630 3.7710 7.9520 3.2600 7 .9650 7.7600 7.7450 7 . U5 10 7.2220 7.2330 7 . 1050 6.3360 6.9390 7.0040 5.2220 6.7360 6.7730 6 . 1690 5 . 3480 6.0810 5.8500 5.3620 5 . 1530 213 TA3LE C-l5: CONTINUED. NUMBER X COORDINATE 236 237 233 239 240 241 242 24 3 244 245 245 247 243 249 250 251 252 253 254 255 255 257 253 259 250 261 262 263 254 265 265 9.4050 9 . 5r790 9.7140 9.3530 9.1030 9.3750 9.4990 9.4000 9.4950 9.3350 9.5220 9.5340 9 . 1740 9 . 1490 9.5550 9.7050 9.-3310 9.0460 9.0040 9.1410 9.2990 9.09 30 9 . 1000 9.6610 9 . 67 30 9.8100 9.4840 9.3350 0.0090 9.4320 9.7550 Y COORDINATE 5 . 1440 5 . 1180 4,78 40 4.5670 4.0690 4.0420 4.0150 3.8490 3.8360 3.6330 3.6310 3.5020 3.4270 3.1970 3.0530 2.8860 2.4520 2.5690 1.5320 1.6710 1.4520 1.9280 . 9405 1.6810 1.4890 1.5730 .3615 . 8496 . 6456 60PQ .5013 . 214 TABLE C-16: ARMYWORM DISTRIBUTION IN FIELD 555 PLOT 2 DATE 80577. NUMBER 1 2 3 4 5 5 7 8 9 10 11 12 13 14 15 15 17 13 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 24 35 36 37 38 39 40 X COORDI NATE . 6768 . 3820 .2769 .9455 1.^110 1.9730 1 .4420 1.9890 1.2300 1.9000 1 . 2 2 80 1.29 3 0 1.2680 2.8540 2.5340 2.8120 2.1480 3.5860 3.5540 3. 1470 3.8560 3.4260 3.7640 3.3330 3.2100 3.2030 3.2730 4.5910 4.5010 4.4220 4.5430 4 . 6?50 4.5730 4.9210 4.9150 5.4940 5.4000 5.3170 5.I960 5.7660 Y COORDI NATE 1 .4430 6.4000 3.7050 9.2110 Q . 37 1 0 9.1860 8.6560 3.1870 5.8940 5.2030 2.7990 2.3060 1.7140 5.3020 7.4720 7.7440 7.7190 7 .3930 6.6340 5.9060 5.2530 4.8460 4.8460 4.6490 4,5250 2 .8110 .8015 .5179 1 .6650 2.7250 3.6370 U. 40?0 4.7230 5.2400 4.5500 . 6239 2.7990 3.3170 3.7850 7.3490 215 TABLE NUMBER >41 M2 '43 44 45 46 47 45 49 50 51 52 53 54 C- 16: CONTI NUED. X COORDI NATE 5.3320 6.2580 5.4070 6.8800 6.6770 5.8580 7.2350 7.6360 7.2690 7.6880 7.8160 8.6100 3.8230 9.2360 Y COORDI NATE 7.8550 7.7190 4.7230 2.8930 2.6260 1.8370 .5055 4.7970 5.7830 6.4490 6.7690 8.6440 8.6630 2.9350 216 TABLE C-17: ARMYWORM DI STRI BUTI ON IN FI ELD 555 PLOT 3 DATE 8 1 2 7 7 . NUMBER 1 2 3 A 5 6 7 8 9 10 11 12 13 1A 15 16 17 13 19 20 21 22 23 24 25 X COORDINATE . 3834 . 5636 .5560 1.2570 1.2710 1.1990 1.5030 1.7790 1.7880 1.3690 2.7750 2.4930 4.5560 5.3450 5.3360 4.3330 6.7590 7.9500 7.3710 7.3460 7.7970 7.7830 8.5230 8.4890 3.9150 Y COORDINATE 1.5920 7.1130 9. 1350 9.8220 6.2130 5 . 1590 4.5240 4.5770 2 . 1790 . 1063 . 287 0 3.3620 8.4070 8.8440 1.5990 . 2354 . 5053 7.2510 3.2100 4.8270 1.1360 .2995 . 4949 . 3018 7.3630 217 TABLE C- 18: ARMYVORM D I S T R I B U T I O N I N F I E L D 5 5 5 PLOT 4 DATE 8 1 6 7 7 . NUMBER 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 16 X COORDI NATE . 6839 . 6242 . 6131 1.5710 1. 1 . 5430 2.5670 2 . 6930 4 . 5 4 60 4.6610 5.6070 5.5470 5.5430 8.5560 8.5800 8 .5910 Y COORDI NATE 9.4870 7.5170 6.4500 5.5370 4 . SOS 0 3.5080 3.4730 3.4690 .5346 7.5230 5.4660 4.5210 3.5370 2.4590 3.4630 4.4650 APPENDIX D DEGREE-DAY ACCUMULATIONS FOR CASS, BAY AND LENAWEE COUNTIES FROM APRIL 1, 1976 TO SEPTEMBER 30, 1976 218 219 Table D-l: Degree-Day Accumulations f o r Paw Paw, Cass County 1976. °D >46°F DAY 1 2 J 4 5 6 7 8 9 10 n 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 APRL 0.0 3.3 12.5 14.6 16.7 22.2 24.9 25.2 28.2 35.6 3o. 6 36.5 43.0 bO. 5 35.0 111 .0 133.0 165.0 177.5 189.0 205.0 217.5 224.7 231.8 231 .8 231.8 231.8 234.4 239.8 246.2 NAY 253.5 255.2 255.2 261.6 282.6 282.6 283.5 287.4 300.9 317.4 322.9 328.8 342.2 362.2 380.7 401.2 408.7 413.2 420.5 439.5 452.5 461.1 469.1 477.8 487.2 498.9 513.9 531.4 547.4 567.9 590.4 JUNE 610.4 623.5 639.2 660.7 633.2 705.7 727.2 752.7 780.2 811 .2 839.7 865.7 899.2 932.7 966.7 981.7 1003.2 1030.2 1047.2 1064 2 1082.2 1107.2 1129.7 1149.7 1171.7 1198.2 1227.2 1255.7 1276.2 1292.2 JULY 1310.2 1329.2 1347.2 1368.7 1393.7 1419.2 1444.2 1469.2 1497.2 1535.7 1571.7 1589.2 1605.9 1640.4 1673.4 1695.9 1713.9 1739.9 1769.4 1804.4 1835.4 1859.4 1891.4 1921.9 1946.4 1976.9 2005.4 2028.4 2052.9 2077.9 2100.0 AUG SEPT 2119.4 2135.9 2152.4 2173.9 2199.9 2219.9 2233.4 2248.9 2269.9 2293.9 2323.4 2354.9 2384.4 2407.4 2425.4 2440.2 2457.7 2478.2 2504.7 253G.7 2558.7 2558.7 2619.2 2647.7 2675.7 2706.2 2739.7 2769.2 2783.2 2796.5 2822.5 2843.5 2856.1 2879.1 2904.6 2918.6 2935.3 2958.3 2988.8 3006.3 3016.9 3035.4 3057.4 3080.4 3106.9 3124.4 3139.4 3161.9 3178.9 3198.4 3213.9 3220.0 3226.2 3238.2 3245.7 3255.7 3263.2 3276.2 3281.4 3292.0 3306.5 220 Table D-2: Degree-Day Accumulations f o r Saline, Ohio, 1976. ° D >46°F DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 APRL 0.0 2.1 6.1 10.4 13.5 18.7 21.7 21.7 23.4 28.9 28.9 30.2 34.4 46.2 69.2 94.2 118.2 141.7 163.7 175.2 188.2 201.2 207.7 212.8 212.8 212.8 213.1 217.2 222.0 228.8 MAY JUNE JULY AUG 237.8 245.1 250.2 265.7 265.9 273.2 384.6 273.2 284.6 298.1 308.1 314.3 323.3 337.3 355.3 371.8 383.3 390.6 398.4 412.5 426.5 433.1 439.7 447.3 454.8 464.1 474.6 488.2 503.2 523.7 545.2 565.7 579.2 593.7 608.9 626.3 649.3 673.8 702.3 729.3 755.8 787.3 808.8 835.8 868.8 898.8 920.3 934.6 957.6 978.6 996.6 1014.6 1036.1 1057.1 1077.1 1102.6 1125.1 1151.6 1177.6 1205.6 1223.6 1239.6 1260.6 1277.6 1299.1 1328.1 1354.1 1380.1 1404.4 1422.1 1453.6 1480.6 1502.6 1519.2 1546.7 1577.2 1604.2 1619.8 1640.3 1664.3 1690.8 1717.3 1740.8 1770.3 1797.8 1817.3 1840.8 1870.8 1895.3 1921.3 1945.8 1971.3 1988.3 2004.3 2018.8 2034.6 2057.1 2073.6 2088.1 2103.1 2120.6 2139.8 2161.3 2193.3 2220.8 2242.3 2260.3 2274.4 2290.8 2308.6 2327.1 2347.1 2368.1 2392.1 2418.6 2444.1 2466.6 2493.1 2522.6 2548.6 2560.2 2571.4 2589.3 SEPT 2607.8 2618.3 2633.8 2659.3 2675.3 2687.9 2706.3 2734.3 2755.3 2766.2 2786.2 2806.2 2824.7 2843.4 2858.4 2873.4 2891.4 2907.9 2923.5 2938.0 2943.8 2948.5 2958.8 2964.6 2972.8 2979.3 2989.8 2995.5 3004.2 3016.7 221 Table D-3 : Degree-Day Accumulations f or Standish, Bay County 1976. ° D >46° F DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 APRL 0.0 1.8 3.1 3.1 5.6 9.5 9.5 9.5 11.5 14.8 14.8 15.3 12.4 33.5 48.6 72.1 95.6 117.1 134.6 141.2 147.6 154.2 157.9 157.9 157.9 157.9 158.9 163.9 169.8 175.8 MAY JUNE JULY AUG SEPT 184.6 187.2 187.2 187.2 205.5 205.5 206.3 210.9 223.7 235.5 238.1 243.8 252.1 270.1 280.2 292.3 299.3 303.7 312.4 328.8 341.5 347.0 349.8 354.1 359.6 367.3 380.1 394.1 405.6 421.6 443.6 457.6 467.6 479.5 496.5 512.5 530.5 555.5 583.5 615.0 642.0 674.0 691.5 720.5 752.5 781.5 799.5 821.5 845.0 862.5 880.0 899.0 920.5 942.5 962.0 988.0 1013.5 1050.5 1077.0 1094.5 1107.5 1122.0 1142.0 1161.0 1181.5 1205.5 1234.0 1253.5 1270.0 1289.5 1319.5 1352.5 1371.0 1389.0 1414.5 1439.0 1461.0 1482.0 1501.5 1524.5 1547.0 1567.5 1592.0 1617.5 1636.0 1655.0 1682.5 1711.5 1732.5 1754.0 1777.0 1796.0 1813.0 1825.0 1844.0 1860.5 1876.5 1889.0 1901.9 1917.4 1936.9 1955.9 1984.9 2013.9 2042.9 2059.4 2072.4 2087.0 2106.5 2125.5 2146.5 2173.5 2197.5 2226.0 2246.5 2263.5 2284.5 2307.5 2338.5 2362.5 2375.2 2385.0 2402.6 2415.1 2424.1 2439.6 2458.6 2471.6 2483.8 2504.8 2532.8 2548.8 2559.8 2580.8 2601.3 2621.8 2642.8 2654.8 2668.8 2689.3 2709.3 2730.3 2742.8 2747.6 2751.4 2756.3 2762.0 2764.5 2767.6 2773.9 2778.9 2788.0 2798.1 APPENDIX E RESULTS OF THE NEAREST NEIGHBOR ANALYSIS OF 1976 AND 1977 DATA 222 223 Table F.-1: F IE L D - Nearest Neiahbor S t a t is t ic s o f Field Data in Cass County 1976 N DATE PLOT NEIGHBOR D ISTANCE CLARK AND EVANS MEAN VARIANCE C TEST R TEST 1 1 1 -3 1 1 1 -2 1 1 1 -1 22 2 -1 2 2 2 -2 5 5 5 5 5 82976 81776 81276 81276 81776 .4 2 0 1 .7 2 8 5 .6 7 0 1 1 .1 2 8 8 2 .3 9 5 5 .0 4 1 7 .3 9 6 0 .0 7 0 5 .6 9 5 5 2 .8 6 7 8 1 .6 6 0 8 1 .2 8 8 7 2 .1 3 2 7 .9 3 2 9 1 .1 4 4 6 .6 1 1 7 .6 9 9 7 .5 0 1 4 .7 8 1 9 1 .2 6 7 6 2 2 2 -3 3 3 3 -1 3 3 3 -2 3 3 3 -3 3 3 3 -4 5 5 5 5 5 82976 80976 81276 82376 84876 1 .1 3 1 8 .3 8 4 0 .1 5 4 7 .9 1 6 6 .8 9 7 5 .7 5 1 8 .1 6 0 2 .0 0 1 5 .1 3 9 5 .2 4 1 2 .7 8 6 4 .8 2 1 7 2 .8 5 8 0 .0 4 5 3 .6 7 6 3 .8 1 6 2 .8 0 5 6 .3 3 1 9 .9 8 9 4 .8 4 1 9 4 4 4 -1 4 4 4 -2 4 4 4 -3 4 4 4 -4 4 4 4 -5 5 5 5 5 5 80976 81276 81776 82376 82876 .2 5 2 4 .4 1 6 1 .3 9 5 1 .4 3 4 1 1 .0 5 3 0 .0 0 6 9 .1 3 3 5 .0 5 6 0 .0 9 7 4 1 .1 9 7 0 2 .1 9 5 2 2 .3 6 0 5 3 .0 1 5 3 2 .7 4 6 3 1 .1 2 7 7 .4 8 6 8 .4 4 8 2 .2 9 5 1 .3 5 8 0 1 .2 6 3 6 1 1 1 -3 1 1 1 -2 1 1 1 -1 2 2 2 -1 2 2 2 -3 10 10 10 10 10 82976 81776 81276 81276 82976 .5 7 9 4 .4 5 7 4 .6 0 8 0 .8 4 6 3 1 .8 4 6 2 .1 9 3 3 .2 0 6 8 .0 3 4 2 .1 0 6 2 1 .7 1 7 0 .9 4 5 9 3 .3 9 5 6 3 .2 9 7 3 2 .5 0 2 6 2 .0 0 4 5 .8 4 3 8 .4 3 8 7 .4 5 5 0 .5 8 6 3 1 .3 3 1 3 33 3 -1 3 3 3 -2 3 3 3 -3 3 3 3 -4 4 4 4 -1 10 10 10 10 10 80976 81276 82376 82876 80976 .3 5 9 3 .3 1 7 0 .9 6 3 5 .8 7 3 7 .3 1 0 0 .0 8 4 7 .0 6 1 1 .4 1 2 5 .3 5 2 2 .0 5 2 0 1 .4 8 9 8 1 .9 3 6 1 .2 2 8 4 1 .0 9 1 3 2 .4 3 3 1 .7 5 3 7 .6 8 0 0 1 .0 3 7 8 .8 1 9 6 .5 9 7 8 4 4 4 -2 4 4 4 -3 4 4 4 -4 4 4 4 -5 1 1 1 -3 10 10 10 10 20 81276 81776 82376 82876 82976 .4 5 6 7 .7 3 6 7 .8 2 5 7 .6 0 5 9 .5 3 9 8 .1 2 5 5 .5 0 4 0 .6 8 1 3 .1 5 4 4 .1 9 6 8 3 .0 7 4 2 1 .5 9 3 0 1 .9 3 0 4 1 .6 5 1 2 1 .8 3 0 8 .4 8 1 8 .7 3 6 7 .6 8 0 9 .7 2 7 1 .7 8 6 0 11 1 -2 3 3 3 -1 3 3 3 -2 3 3 3 -3 3 3 3 -4 20 20 20 20 20 81776 80976 81276 89276 82876 .9 6 4 2 .4 4 6 8 .1 8 1 8 1 .0 9 4 2 .8 3 5 6 .6 4 0 8 .0 7 9 1 .0 0 4 7 .4 2 2 0 .7 4 9 8 .6 4 3 2 .5 3 6 8 5 .2 2 0 4 1 .5 2 7 5 1 .8 4 8 3 .9 2 4 8 .9 3 7 6 .3 8 9 9 1 .1 7 8 5 .7 8 3 8 224 4 4 4 -1 4 4 4 -2 4 4 4 -3 4 4 4 -5 1 1 1 -3 20 20 20 20 30 80976 81276 91776 82876 92976 .4 1 2 6 .8 5 6 6 .5 3 7 4 .9 1 9 5 .4 5 2 6 ' .0 7 9 7 .5 1 8 0 .3 4 2 0 .5 1 8 3 .1 4 1 9 1 .7 4 7 6 .6 6 2 3 3 .9 5 8 2 .8 8 4 5 3 .4 2 1 3 .7 9 5 7 .8 2 2 6 .5 3 7 4 1 .1 0 3 4 .6 7 3 5 3 3 3 -1 3 3 3 -2 4 4 4 -1 4 4 4 -5 1 1 1 -3 30 30 30 30 40 80976 81276 80976 82876 82976 .2 3 5 1 .1 5 7 3 .2 6 0 1 .5 9 7 6 .4 7 4 8 .0 1 3 3 .0 0 2 8 .0 1 6 4 .2 7 1 0 .1 3 1 3 5 .3 1 1 0 6 .9 4 2 2 5 .2 2 2 6 2 .9 6 4 4 3 .7 3 4 5 .4 8 3 1 .3 3 7 5 .5 0 1 6 .7 1 7 1 .6 9 1 6 33 3 -1 33 3 -2 4 4 4 -1 1 1 1 -3 3 3 3 -1 40 40 40 50 50 80976 81276 80976 82976 80976 .2 9 3 6 .2 7 3 6 .3 8 9 3 .4 6 9 2 .3 0 4 9 .0 3 3 4 .0 5 8 9 .0 4 6 5 .1 3 3 7 .0 3 3 7 4 .6 4 8 3 4 .9 9 8 4 4 .4 1 4 2 4 .2 8 6 5 5 .0 1 1 0 .6 1 5 9 .5 8 6 9 .6 3 5 2 .6 8 3 1 .6 2 9 6 3 3 3 -2 4 4 4 -1 3 3 3 -1 50 50 76 81276 80976 80976 .2 4 6 7 .3 2 6 3 .2 3 9 5 .0 2 6 5 .1 1 5 5 .0 7 5 1 6 .3 7 0 8 5 .0 1 4 6 4 .1 0 9 4 .5 2 9 0 .6 2 9 3 .7 5 1 9 T a b le E -2 : N e a re s t n e ig h b o r s t a t i s t i c s Cass C o u n ty 1977 F IE L D - o f c o lle c te d NEIGHBOR D ISTAN C E PLOT N DATE 5 5 5 -1 5 5 5 -2 5 5 5 -3 5 5 5 -4 5 5 5 -1 5 5 5 5 10 72977 80577 81277 81677 72977 .3 5 7 2 .4 7 9 6 .8 9 0 0 1 .0 9 0 7 .2 4 0 3 5 5 5 -2 55 5 -3 5 5 5 -4 5 5 5 -1 5 5 5 -2 10 10 10 20 20 68577 81277 81677 72977 80577 5 5 5 -3 5 5 5 -1 5 5 5 -2 5 5 5 -1 55 5 -2 20 30 30 40 40 5 5 5 -1 55 5 -2 5 5 5 -1 5 5 5 -1 5 5 5 -1 5 5 5 -1 5 5 5 -1 5 5 5 -1 5 5 5 -1 MEAN VARIANCE fie ld d a ta in CLARK AND EVANS C TEST R TEST .0 5 9 9 .0 1 0 4 .1 7 5 4 .0 3 4 4 .0 0 8 1 .7 0 6 5 1 .2 6 2 3 .4 7 0 8 .5 4 5 0 1 .3 0 8 4 1 .1 6 5 2 .7 0 4 9 .8 9 0 0 .8 7 2 6 .7 8 3 7 .6 4 5 3 1 .1 8 4 3 1 .0 5 1 2 .3 1 3 5 .5 6 6 9 .1 4 6 3 .3 2 0 7 .0 1 7 0 .0 7 1 3 .0 6 0 6 .3 1 2 5 1 .1 1 5 2 .9 6 2 1 .1 9 2 5 1 .4 2 6 9 .8 4 8 3 1 .1 8 4 3 .8 4 1 0 1 .0 2 2 5 .8 3 3 2 81277 72977 80577 72977 80577 .8 4 1 6 .2 1 7 5 .5 6 7 6 .2 4 0 3 .6 0 5 9 .1 3 5 7 .0 1 6 8 .0 8 7 5 .0 1 7 6 .0 7 6 0 1 .3 5 5 2 3 .0 4 5 6 1 .7 3 6 5 2 .6 1 4 5 1 .3 2 4 7 .8 4 1 6 .7 8 9 3 .8 3 4 2 .7 8 3 9 .8 9 0 5 50 . 50 60 75 100 72977 80577 72977 72977 72966 .2 8 1 8 .5 6 7 3 .2 4 4 5 .2 7 6 6 .2 3 3 5 .0 2 8 3 .0 5 6 6 .0 2 3 0 .0 2 9 1 .0 1 5 4 1 .0 9 4 6 2 .2 4 8 4 2 .9 7 9 6 1 .6 2 1 7 4 .5 6 1 5 .9 1 9 1 .8 3 3 8 .7 9 8 9 .9 0 2 1 .7 6 1 6 125 150 175 200 72977 72977 72977 72977 .2 6 7 5 .2 5 3 1 .2 7 6 3 .2 8 0 2 .0 3 1 1 .0 2 2 9 .0 3 7 7 .0 3 3 3 2 .7 2 5 3 4 .0 8 5 1 2 .4 9 6 9 2 .3 2 8 3 .8 7 2 6 .8 2 5 7 .9 0 1 3 .9 1 3 9 APPENDIX F DISTRIBUTION STATISTICS OF FIELDS 1 1 1-3 AND 3 3 3-2 226 227 Table F - l : No. o f Ruin D is t ri b u ti o n S t a t is t i c s of Field 111-3, date 8-29-76 T o ta l C a tc h N u m b er o f s a m p l e s : 1 2 " 4 5 6 7 8 2 2 2 3 0 M ean an d S .D . C .V . N u m b er o f s a m p l e s : 6 3 8 7 3 6 9 6 M ean a n d S .D . C .V . I D e lta C h i S q r. Test D is ti 5 6 3 O J 1 2 3 4 5 6 7 8 V a r/M e a n 2 .6 7 .5 0 2 .3 3 .0 1 1 0 .6 7 2 .0 0 C R .7 5 2 .0 0 .7 5 1 .3 3 .0 1 5 .0 0 0 .0 1 .6 7 - 3 .0 0 8 .0 0 3 .0 0 5'. 3 3 - R R R R 1 4 .0 2 7 .0 1 9 .5 1 7 .8 8 7 .0 0 7 .3 3 1 8 .7 8 2 4 .0 0 R C C - 1 . 33± .8 5 6 3 .8 5 - 2 .2 5 ± 4 .0 1 1 7 7 .7 3 10 1 .5 6 3 .0 2 .1 7 1 .9 2 .7 8 .8 2 2 .0 9 2 .6 7 1 .8 8 ± .8 0 4 2 .3 8 2 .0 1 0 .0 2 .5 0 2 .3 9 0 .0 .6 7 2 .2 2 4 .0 0 3 . 4 ± 3 .0 7 9 0 .3 0 c R R C R 228 No. o f R un T o ta l C a tc h N u n b e r o f s a m p le s : 1 2 3 4 5 6 7 8 30 94 119 97 39 76 69 68 M ean a n d S .D . C .V . N u n b er o f s a m p le s : 1 2 3 4 5 6 7 8 131 111 101 97 101 119 97 109 M ean a n d S .D . C .V . V a r /M e a n I D e lta Chi S q r. Test D is ti 70 2 .7 4 7 .1 0 8 .4 7 8 .0 4 2 .2 2 6 .7 5 8 .3 7 5 .6 9 6 . 1 7 ± 2 .4 6 3 9 .9 2 5 .1 5 5 .5 3 5 .3 7 6 .0 6 3 .2 1 6 .2 9 8 .4 7 5 .8 1 1 8 9 .3 4 8 9 .8 5 8 5 .1 5 5 4 .7 1 5 3 .1 4 6 5 .6 5 7 7 .2 3 9 1 .1 C C C C C C C C 6 6 2 .1 5 5 3 .9 7 5 3 .5 6 2 3 .6 4 3 2 .7 6 9 8 .7 5 9 6 .8 4 2 5 .9 C C C 5 .7 4 ± 1 .4 5 2 5 .3 3 100 6 .6 9 5 .6 0 7 .6 1 6 .3 0 4 .3 7 7 .0 6 6 .0 3 4 .3 0 6 .5 6 ± 1 .6 2 2 4 .6 6 5 .3 3 4 .9 2 7 .5 4 6 .4 6 4 .3 7 6 .0 8 6 .1 9 4 .0 3 5 .6 2 + 1 .1 7 2 0 .8 7 c c c c c 229 No. o f Run T o ta l C a tc h N u m b er o f s a m p l e s : 1 2 3 4 5 6 7 8 15 38 30 31 36 11 32 29 m and S .D . 1. N u m b er o f s a m p l e s : 1 2 3 4 5 6 7 8 46 52 58 67 71 58 60 30 ia n and S .D . ,V . V a r./M e a n I D e lta C h i S q r. Test D is tr. 1 .3 4 3 .8 6 1 4 .3 4 3 .0 4 3 .6 4 1 .6 0 4 .1 3 4 .5 3 1 .7 1 3 .2 4 1 4 .3 4 2 .9 7 3 .1 9 2 .7 3 3 .9 3 4 .6 6 3 9 .0 1 1 2 .0 4 1 6 .0 8 8 .0 1 0 5 .7 4 6 .3 1 1 9 .9 1 3 1 .3 R C C C C C C C 4 .5 6 ± 4 .1 2 9 3 .2 8 4 .6 ± 4 .0 3 8 7 .6 3 2 1 2 .7 1 8 6 .5 4 7 9 .9 3 4 2 .7 4 2 8 .3 3 7 8 .2 3 8 0 .0 1 0 6 .7 C C C C C C C C 30 50 4 .3 4 3 .8 1 9 .7 9 6 .9 9 8 .7 4 7 .7 2 7 .7 5 2 .1 8 7 .5 8 + 3 .6 1 4 7 .5 9 4 .6 4 3 .7 0 8 .5 6 5 .4 5 6 .4 2 6 .7 6 6 .6 1 2 .9 9 5 .6 4 3 2 .2 9 230 Table F-2: No. o f Run Distri bu ti o n S t a t i s t i c s o f Field 333-2, date 8-12-76 T o ta l C a tc h N u n fcer o f s a m p l e s : 1 2 3 4 5 6 7 8 2 0 19 7 5 9 7 0 M e a n a n d S! .D . C .V . N u n b e r o f s a m p le s : 1 2 3 4 5 6 7 8 7 8 9 9 27 13 10 3 M e a n a n d S .D . C .V . V a r . /M e a n I D e lt a C h i S q r. Test D is tr. 5 .8 0 5 .0 8 .0 - - - 7 2 .2 0 9 .8 0 1 .5 0 1 6 .2 0 9 .8 - 5 .0 1 .5 5 .0 5 .0 5 .0 6 .0 ± 2 7 .0 4 4 9 .9 4 .4 2 ± 1 .4 3 3 2 .3 - 7 6 .0 2 8 .0 6 .0 3 6 .0 2 8 .0 - R - C C R C C - 10 .9 7 1 .0 6 1 .3 5 2 .5 8 2 0 .9 1 4 .6 2 2 .6 7 .7 8 8 .8 ± 1 9 .3 4 2 1 9 .8 .9 5 1 .0 7 1 .3 9 2 .7 8 7 .8 9 3 .7 2 2 .6 7 - 2 .9 2 ± 2 .4 1 5 5 .8 8 .7 1 9 .5 1 2 .1 1 2 3 .2 2 1 8 8 .2 0 4 1 .6 2 2 4 .0 0 7 .0 0 R R R C C C C R 231 No. o f Run T o ta l C a tc h N u m b er o f s a m p le s : . 1 2 3 4 5 6 7 8 30 34 25 33 32 36 23 27 M ean an d S .D . C .V . N u rrb e r o f s a m p l e s : 1 2 3 4 5 6 7 8 62 39 69 51 55 57 43 57 M e a n a n d S .D . C .V . V a r./M e a n I D e lt a C h i S q r. Test D is tr. 70 1 .4 6 2 .0 7 1 .3 2 2 .1 3 1 .3 8 1 .6 2 1 .9 2 1 .9 8 1 . 74± .3 3 1 8 .8 1 2 .0 9 3 .2 4 1 .8 7 3 .4 5 1 .8 3 2 .2 2 3 .8 7 3 .5 9 C C C C C C 1 0 0 .7 1 4 3 .1 9 0 .8 1 4 7 .3 9 4 .9 1 1 1 .8 1 3 2 .2 1 3 6 .3 c c 1 8 3 .2 1 5 8 .4 1 4 6 .9 1 6 2 .7 1 6 5 .0 1 7 6 .3 1 6 3 .9 1 3 5 .2 C C C C C C C C 2 .7 7 ± .8 5 3 0 .5 8 100 1 .8 5 1 .6 0 1 .4 8 1 .6 4 1 .6 7 1 .7 8 1 .6 5 1 .4 1 1 .6 4 ± .1 4 8 .7 6 2 .3 7 2 .5 6 1 .7 1 2 .2 7 2 .2 2 2 .3 8 2 .5 8 1 .7 7 2.23± .32 14.49 232 No. o f Run T o ta l C a tc h N u n b e r o f s a m p le s : 1 2 3 4 5 6 7 8 n a n d S .D . N u n b er o f s a m p le s : 21 29 29 34 32 23 15 21 san a n d S . D . V. I D e lt a C h i S q r. Test 30 17 17 11 13 19 15 21 7 r 1 2 3 4 5 6 7 8 V a r./M e a n 2 .0 3 3 .1 2 .6 6 1 .9 1 1 .4 1 1 .3 4 1 .5 9 1 .0 8 1 .6 4 ± .7 4 4 5 .1 9 2 .8 7 4 .8 5 .7 8 2 .5 4 2 .5 0 1 .7 1 1 .8 6 1 .4 2 5 8 .9 9 0 .7 1 9 .0 5 5 .3 4 1 .0 3 9 .0 3 6 .1 3 1 .6 2 . 3 2 ± 1 .2 3 5 2 .9 1 50 2 .0 4 1 .2 7 1 .6 9 1 .4 1 1 .7 7 1 .2 5 .8 5 2 .2 4 1 .5 7 + .4 6 2 9 .0 9 3 .5 7 1 .4 7 2 .1 7 1 .6 0 2 .2 1 1 .4 5 .4 8 4 .0 4 2 .1 2 ± 1 .1 7 5 5 .3 3 1 0 0 .4 6 2 .4 8 3 .1 6 8 .9 8 6 .8 6 1 .3 4 1 .7 1 0 9 .9 D is tr. APPENDIX G CALCULATIONS OF RELATIVE NET PRECISION FOR 1976 DATA 233 234 F ie ld 1 1 1 -3 D a te : 8 -2 9 -7 6 F ie ld 1 1 1 -2 D a te : U n i t S iz e Su2 RNP U n it S i z e Su2 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .4 1 .5 0 .5 9 1 .2 3 1 .5 9 1 .7 5 1 .2 0 2 .2 6 2 .5 6 1 .9 1 2 .3 0 1 .8 8 3 .3 8 3 .5 5 4 .2 5 4 .1 9 4 .7 1 5 .2 3 5 .2 1 1 4 .4 5 2 4 .0 0 2 8 .5 5 1 6 .2 6 1 8 .1 1 2 1 .1 3 3 7 .4 3 2 2 .4 0 2 2 .0 1 3 4 .7 1 3 3 .3 9 4 3 .8 5 2 7 .6 1 2 7 .8 6 2 5 .6 3 2 8 .4 4 2 6 .7 1 2 6 .3 0 2 8 .4 4 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .0 5 .1 7 .2 5 .3 5 .2 8 .4 4 .3 2 .7 2 .3 1 .6 5 ■ .7 1 1 .2 3 1 .2 5 .7 8 .9 2 1 .5 9 1 .0 6 1 .4 0 1 .5 6 8 -1 7 -7 6 RNP 1 1 8 .5 2 7 0 .5 9 6 7 .3 7 5 7 .1 4 1 0 2 .8 6 8 4 .0 5 1 4 0 .3 5 7 0 .3 1 1 8 1 .7 4 1 0 2 .0 0 • 1 0 8 .7 1 6 7 .0 2 7 4 .5 7 1 2 6 .8 0 1 1 8 .4 1 7 4 .9 5 1 1 8 .7 0 9 8 .2 3 9 4 .9 7 235 F ie ld 2 2 2 -2 D a te : 8 -1 7 -7 6 F ie ld 2 2 2 -3 D a te : 8 -2 9 -7 6 U n i t S iz e Su2 RNP U n i t S iz e Su2 RNP .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .1 3 .0 1 .0 5 .1 5 .1 1 .1 5 .3 1 .2 3 .2 8 .0 9 .2 6 .2 4 .2 6 .4 9 .2 5 .4 8 .3 3 .3 7 .6 3 4 5 .5 8 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .0 3 .6 3 .8 4 .0 .0 9 .0 6 .1 1 .1 6 .1 3 .2 2 .2 8 .2 9 .2 4 .3 0 .3 6 .2 7 .3 2 .3 9 .4 5 .5 7 .7 0 .6 3 .5 8 6 5 .8 4 2 0 0 .0 1 5 3 .1 1 1 2 5 .0 0 2 2 1 .5 4 1 6 8 .1 0 1 6 0 .4 0 1 7 4 .5 7 2 3 4 .7 4 2 2 1 .0 0 2 1 3 .3 3 3 0 5 .3 3 2 9 1 .6 7 2 5 3 .5 9 2 4 2 .0 8 2 0 9 .0 8 1 7 9 .7 5 2 1 8 .2 9 2 5 5 .4 3 F ie ld 4 4 4 -3 U n it S i z e .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 *) D a te : Su2 .0 1 .4 4 .1 1 .2 9 .7 7 .8 5 .3 2 .7 0 1 .3 6 1 .1 0 1 .5 8 2 .3 7 1 .9 9 2 .0 4 1 .6 7 1 .3 6 2 .3 6 2 .1 1 3 .2 0 *) 3 3 6 .8 4 1 3 3 .3 3 2 6 1 .8 2 2 4 6 .5 4 1 4 4 .8 8 2 2 0 .1 1 2 0 1 .2 1 7 3 6 .6 8 2 9 5 .3 8 3 4 3 .5 0 3 5 8 .9 7 2 0 1 .8 4 4 3 5 .7 4 2 4 8 .2 8 3 8 1 .2 9 3 7 1 .6 9 2 3 5 .1 6 8 -9 -7 6 F ie ld 4 4 4 -4 RNP U n i t S iz e *) 2 7 .2 7 1 5 3 .1 1 6 8 .9 7 3 7 .4 0 4 3 .5 1 1 4 0 .3 5 7 2 .3 2 3 7 .2 2 6 0 .2 7 4 8 .6 1 3 4 .7 8 4 6 .9 0 4 8 .4 8 6 5 .2 3 8 7 .6 3 5 3 .3 2 6 5 .1 8 4 6 .3 0 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 o n ly o n e i n d i v i d u a l c o u n t. D a te : Su2 .1 1 .1 4 .2 8 .3 1 .3 2 .3 5 .7 4 .4 1 .5 1 .7 1 .6 3 .7 8 .9 4 .7 0 1 .1 0 .8 2 1 .5 2 1 .4 4 1 .6 8 8 -1 7 -7 6 RNP 5 3 .8 7 8 8 .7 1 6 0 .1 5 6 4 .5 2 9 0 .0 1 0 5 .6 6 6 0 .4 9 1 2 3 .4 8 9 9 .2 6 9 3 .3 8 1 2 1 .9 0 1 0 5 .6 9 9 9 .2 9 1 4 1 .2 .9 9 9 .0 3 1 4 5 .3 4 8 2 .7 8 9 5 .5 0 8 8 .1 8 236 F ie ld 3 3 3 -1 U n it S i z e .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 F ie ld 3 3 3 -3 D a te : Su2 1 .5 2 2 .5 4 3 .8 5 5 .3 6 2 .2 3 7 .6 3 8 .1 5 9 .9 4 1 9 .7 0 1 5 .6 0 1 8 .2 6 1 5 .9 7 1 7 .4 4 3 3 .4 4 1 6 .2 5 2 8 .6 2 3 5 .4 9 3 2 .6 2 3 7 .5 3 D a te : 8 -9 -7 6 F ie ld 3 3 3 -2 RNP U n i t S iz e 3 .9 0 4 .7 2 3 .7 3 1 2 .9 1 4 .8 5 5 .5 1 5 .0 9 2 .8 6 4 .2 5 4 .2 1 5 .1 6 5 .3 6 2 .9 6 6 .7 0 4 .1 6 3 .5 5 2 .5 5 4 .2 2 3 .9 2 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 2 .4 3 .6 3 .8 4 .0 8 -2 3 -7 6 F ie ld 4 4 4 -2 D a te : Su2 1 .3 1 2 .8 9 8 .8 3 7 .2 5 5 .0 1 2 7 .4 2 6 .8 5 2 6 .4 1 1 5 .4 4 9 .4 2 1 9 .1 0 9 .4 8 1 3 .2 3 2 0 .1 3 1 7 .4 9 2 4 .7 5 2 8 .8 4 2 3 .8 7 1 3 .7 8 D a te : 8 -1 2 -7 6 RNP 4 .5 2 4 .1 5 1 .9 1 2 .7 6 5 .7 5 1 .3 5 6 .5 6 1 .9 2 3 .6 5 7 .0 4 4 .0 2 8 .7 0 7 .0 5 4 .9 1 6 .2 3 4 .8 2 4 .3 6 5 .7 6 1 0 .7 5 8 -1 7 -7 6 U n i t S iz e Su2 RNP U n it S i z e Su2 RNP .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .1 2 .1 8 .3 5 .3 7 .3 8 .4 9 .4 5 .5 8 .5 3 .6 3 .8 5 .8 1 .9 3 1 .1 8 1 .0 1 1 .2 8 1 .1 8 1 .2 9 1 .0 8 8 .3 3 6 6 .6 7 4 8 .1 2 5 4 .0 5 7 5 .7 9 7 5 .4 9 9 9 .8 1 8 7 .2 8 1 0 6 .3 0 1 0 5 .2 4 9 0 .3 5 1 0 1 .7 8 1 0 0 .3 6 8 3 .8 1 1 0 7 .8 6 9 3 .1 1 1 0 6 .6 3 1 0 6 .6 1 1 3 7 .7 1 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .3 4 .3 2 .7 8 1 .1 1 .2 8 .6 7 .9 2 1 .0 6 .6 5 2 .9 5 1 .4 7 1 .1 8 1 .7 0 1 .8 7 1 .2 0 2 .2 9 2 .8 7 1 .3 9 1 .6 7 1 7 .4 3 3 7 .5 0 2 1 .5 9 1 8 .0 2 1 0 2 .8 6 5 5 .2 0 4 8 .8 2 4 7 .7 6 7 7 .8 8 2 2 .4 8 5 2 .2 4 6 9 .8 6 5 4 .9 0 5 2 .8 9 9 0 .7 8 5 2 .0 4 4 3 .8 4 1 0 0 .3 8 8 8 .7 1 237 F ie ld 3 3 3 -4 U n i t S iz e .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 F ie ld D a te : Su2 .0 5 .1 5 .2 0 .1 5 .1 8 .1 8 .2 6 .4 0 .5 0 .4 4 .3 8 .6 2 .5 6 .5 8 .7 1 .5 1 .5 7 .6 3 .9 6 4 4 4 -2 D a te : U n i t S iz e Su2 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .3 4 .3 2 .7 8 1 .1 1 .2 8 .6 7 .9 2 1 .0 6 .6 5 2 .9 5 1 .4 7 1 .1 8 1 .7 0 1 .8 7 1 .2 0 2 .2 4 2 .8 7 1 .3 9 1 .6 7 8 -2 8 -7 6 F ie ld 4 4 4 -1 D a te : 8 -9 -7 6 RNP U n i t S iz e Su2 RNP 1 1 8 .5 2 8 0 .0 8 4 .2 1 1 3 3 .3 3 1 6 0 .0 0 2 0 5 .4 5 1 7 2 .7 4 1 2 6 .5 6 1 1 2 .6 8 1 5 0 .6 8 2 0 2 .1 1 1 3 2 .9 7 1 6 6 .6 7 1 7 0 .5 2 1 5 3 .4 3 2 3 3 .6 8 2 2 0 .7 5 2 1 8 .2 9 1 5 4 .3 2 .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .5 7 1 .5 3 1 .5 1 2 .4 7 1 .8 4 4 .8 5 3 .3 7 4 .8 1 6 .5 9 5 .9 9 6 .8 1 6 .5 5 7 .4 9 1 2 .3 5 9 .0 6 8 .2 9 1 4 .5 0 1 3 .9 4 9 .9 5 1 0 .4 0 7 .8 4 1 1 .1 5 8 .1 0 1 5 .6 5 7 .6 2 1 3 .3 3 1 0 .5 2 8 .5 5 1 1 .0 7 1 1 .2 8 1 2 .5 9 7 .8 4 8 .0 1 1 2 .0 2 1 4 .3 8 8 .6 8 9 .8 7 1 4 .8 9 8 -1 2 -7 6 RNP 1 7 .4 3 3 7 .5 0 2 1 .5 9 1 8 .0 2 1 0 2 .8 6 5 5 .2 0 4 8 .8 2 4 7 .7 6 8 6 .6 7 2 2 .4 8 5 2 .2 4 6 9 .8 6 5 4 .8 0 5 2 .8 9 9 0 .7 8 5 3 .2 0 4 3 .8 4 9 8 .9 4 8 8 .7 1 F ie ld 4 4 4 -5 D a te : 8 -2 8 -7 6 U n i t S iz e Su2 RNP .4 .6 .8 1 .0 1 .2 1 .4 1 .6 1 .8 2 .0 2 .2 2 .4 2 .6 2 .8 3 .0 3 .2 3 .4 3 .6 3 .8 4 .0 .1 8 .3 0 .3 2 .3 8 .3 2 .8 7 .5 9 .7 2 .9 5 .6 5 1 .1 1 1 .2 8 1 .5 4 1 .5 9 1 .3 3 1 .2 9 1 .7 3 1 .3 6 1 .4 4 3 2 .9 2 4 0 .0 5 2 .6 3 5 2 .6 3 9 0 .0 4 2 .5 1 7 6 .1 2 7 0 .3 1 5 9 .3 0 1 0 .2 0 6 9 .1 6 6 4 .4 1 6 0 .6 1 6 2 .2 0 8 1 .9 1 9 2 .3 8 7 2 .7 3 1 0 1 .1 2 1 0 2 .8 8 APPENDIX H FOOD CONSUMPTION RATES OF INDIVIDUAL LARVA FED WITH BARLEY, DOWNY WHEAT, AND CORN LEAVES 238 Table H-l: Kate of food consumption of arrayvrorm larvae fed on barley leaves (cm2 leaf area) INSTAR/DAY NUMBER OF INDIVIDUALS AVERAGE 1 2 3 4 5 6 7 1 .05 .05 .12 .04 .12 .06 2 .17 .20 .15 .24 .16 .15 .27 .19 3 .08 .05 .08 .06 .13 .02 .06 .07 4 .07 .31 .10 .10 .04 .16 .15 .13 5 .20 .22 .17 .16 .14 .15 .46 .21 6 .76 .50 .55 .35 1.05 1.00 1.07 .75 7 1.03 1.10 1.20 1.70 1.70 1.65 1.15 1.36 8 1.46 1.46 1.35 2.20 1.22 1.44 2.22 1.62 9 5.26 4.87 6.20 5.01 7.19 5.01 5.09 5.51 Instar I 0 .06 2 39 Instar II Instar III Instar IV Table H-l (continued) In s t a r V 10 2 .5 3 4 .7 2 3 .2 8 2 .9 1 2 .6 6 6 .2 6 5 .3 4 3 .9 6 11 1 0 .1 5 9 .3 2 9 .6 8 9 .2 1 9 .2 7 1 2 .1 8 1 0 .5 2 1 0 .0 4 12 1 5 .6 0 1 9 .3 6 1 5 .7 3 1 4 .2 7 5 .6 2 1 4 .4 8 1 1 .5 8 1 3 .3 1 In s t a r V I • 1 1 .0 7 1 0 .0 4 9 .0 5 8 .0 2 4 .5 5 9 .0 7 9 .0 7 8 .7 8 14 3 2 .0 3 2 7 .7 7 2 6 .5 7 2 3 .3 8 9 .0 4 2 7 .9 7 3 0 .8 5 2 5 .3 8 15 3 0 .8 1 2 8 .6 6 3 0 .0 2 3 0 .3 5 , 2 9 .7 3 3 0 .3 0 3 0 .0 7 2 9 .9 9 16 4 6 .3 7 4 2 .5 8 4 4 .0 7 4 2 .3 7 4 3 .2 6 4 4 .8 7 4 1 .1 5 3 7 .6 3 17 5 7 .0 1 5 6 .1 8 5 6 .2 1 5 7 .2 1 5 9 .6 8 6 2 .8 1 6 2 .3 0 5 8 .7 7 18 4 1 .9 5 4 4 .7 1 3 9 .4 5 4 4 .1 6 4 1 .7 5 5 6 .9 0 4 0 .5 7 4 4 .2 2 19 1 6 .5 0 1 5 .8 8 1 4 .7 3 1 8 .7 1 1 4 .9 1 4 3 .8 6 1 6 .3 2 2 0 .1 3 P rep u p a 20 0 0 0 0 0 0 0 21 0 0 0 0 0 0 0 TOTAL 262.61 240 13 241 H-2: No Leaf Area Consumed by Armyworm Larvae (cm2 barley l e a f area) Instar II III IV VI TOTAL 1 19 .21 1.55 7.15 39.67 2 7 5 .6 2 324.39 2 17 .15 .96 7.75 28.28 2 3 5 .7 4 1 7 3 .0 5 3 25 .36 .72 7.43 33.40 2 2 5 .8 4 268. 4 27 .18 .7 2 8.75 28.69 220.10 2 5 8 .7 1 5 28 . 16 .51 8.91 26.39 224.20 260.45 6- 27 .27 .4 5 10.88 29.38 260.23 301.48 7 28 .17 1.19 10.11 1 7. 55 202.82 232.12 8 21 .18 1.15 8.10 32.92 275.78 318.34 9 21 . 17 .41 10.44 21.98 227.40 2 6 0 .6 1 10 27 .21 1.53 8.61 27.44 230.93 268.99 11 12 .12 6.94 6.74 43.46 209.79 2 6 7 .1 7 12 31 .51 14.32 9.53 46.03 1 8 3 .5 6 254.26 13 24 .33 10.83 9.24 65.35 208.25 294.24 14 31 .24 6.94 9.82 44.19 1 8 3 .0 8 244.58 15 12 .20 12.66 9.17 39.16 1 8 4 .4 9 245.8 eai . 21 .23 4.06 8.84 54.93 223.19 271.46 % .08 .08 1.50 3.26 12.86 82.22 100 242 Table H-3: Rate o f Food Consumption of ArnTyworm Larvae Fed on Downey Wheat Leaves (cm2 l e a f area) INSTAR/DAY NUMBER OF INDIVIDUALS AVERAGE 1 2 3 1 .07 .07 .07 .07 2 .06 .06 .06 .0 6 3 .09 .09 .09 .09 4 .17 .17 .17 . 17 5 1.20 1.20 1.20 1.20 6 1.64 1.64 1. 6 4 1.64 7 2.12 1.13 1.50 1.58 8 1.97 1.57 1.90 1.8 1 9 1.35 1.88 1. 7 7 1. 6 7 10 3.41 8.17 3.28 4.95 11 5.73 3.48 4.57 4.59 12 4.88 1.55 3.78 3.40 13 5.94 8.18 6.83 6.98 14 3.86 13.49 9.87 9.07 15 5.68 11 .7 1 18 . 8 4 9.68 16 17.82 13.42 20.41 17.22 In star In s ta r Instar Instar I II III IV Instar V In star VI 243 Table H-3 (continued) In s ta r VI 17 18 (continued) 29.60 61.68 32.17 59.0 35.12 55.94 32.30 58.87 19 60.07 60.72 63.41 61.40 20 55.30 8.45 23.55 29.10 21 Prep. 244 Table H-4: Total Leaf Area Consumed by Armyworm Larvae per Instar Fed on Downy Wheat Leaves (cm2 l e a f area) INSTAR NO. TOTAL I II III IV V VI 1 .1 3 .26 2.84 5.44 14.02 2 3 9 .9 4 262.64 2 . 13 .26 2.84 4.58 13.20 2 0 7 .1 4 228.15 3 . 13 .26 2.84 5.17 11.63 2 3 3 .9 7 254.00 4 . 13 .26 2.84 2.66 8.98 214.92 229.77 5 .1 3 .2 6 2.84 5.57 15.72 19 0. 47 214.99 6 .1 3 .2 6 2.84 3.29 11. 37 200.78 2 1 8 .6 7 AVERAGE .1 3 .26 2.84 4.45 12.49 214.54 2 3 4 .7 1 % .06 .11 1.21 1.90 5.32 91.4 100 . 245 Table H-5: Rate o f Food Consumption of Armyworm Larvae Fed by Corn Leaves INSTAR/DAY ________ NUMBER OF INDIVIDUALS____________AVERAGE 2 1 Instar 3 4 I 1 .20 .15 .0 6 .1 9 .15 2 .14 . 16 .09 .14 .1 3 3 .50 .58 .49 .5 8 .5 4 4 .53 .8 4 .45 .63 .6 2 5 .71 1.29 1. 5 3 1. 3 8 1.2 3 6 1.69 1.36 .5.1 1.11 1.16 7 .84 .7 9 .5 6 1.02 .8 0 8 .79 1.26 1.90 1.48 1.36 9 2.90 1.30 3.82 2.50 2.63 10 2.57 .65 1.97 6. 8 1 3.00 11 3.94 4.02 3.32 4.55 3.96 12 5.26 8.37 2.57 2.05 4.56 13 2.33 2.72 4.79 5.61 3.86 14 19.61 22.41 8.71 13.50 15.98 15 15.90 21.22 7.95 7.42 13.12 16 13.46 14.64 13.59 5.64 11.83 Instar I I In star In s t a r III IV In s ta r V 246 Instar VI 17 16.72 23.35 17. 71 18.02 18.95 18 6.97 28.80 11.43 31.64 19 .7 1 19 30.04 17. 11 33.51 50.71 32.84 20 29.80 34.71 64.40 66.63 49.14 21 49.19 71.24 69.60 76.87 66.73 22 46.31 54.40 56.29 15.09 43.02 23 PREPU PREPU PREPU PREPU TOTAL 295.32 Table H-6: Corn Leaves Consumed by Instar of Armyworm Larvae (cm2 leaf area) NO. TOTAL II 1 .34 1.74 3.32 14.67 51.30 179.03 250.40 2 .31 2.71 3.41 14.34 60.99 230.61 312.37 3 .15 2.47 2.97 11.68 34.74 232.94 304.95 4 .33 2.59 3.61 15.91 32.17 258.96 313.57 5 .35 1.88 2.92 18.51 48.59 237.77 310.02 298.27 % .30 .1 V VI 2.28 3.25 14.02 45.56 231.86 .76 1.09 5.04 15.27 77.73 100. 247 I AVERAGE III INSTARS IV