”TV-1. s u:- . n . . .‘r‘! “T, 3;:‘1’3 iu \n‘f‘} U} (3. :3- 833.333) 2.3: 2'." ”I 33:11:13 1‘13? 34 "FM-sis {an 5: Exf'iittf-flfiAfi $323.3? i,:\= ¥ " {51‘3“ iéi“¥¥.@35uw 3?63 e: 2):»ng 2:25? 33... 5. LIBRARY Michigan Statc University S I'DIES OI TIL. 818311-10 CCLI‘YRCL v1 mtvv‘ Trpmr1 f! r O;‘ l. : LK‘J til-.40 ..n-b 5- I L: David H. Gessford A THESIS Subnitted to the College of Agriculture of Iichigan State University of Agriculture and Applied Science in Partial Fulfillment of the Requirements for the Degree of fiASTER OF C 3133 Deoartment of Farm Crocs A 1. Approved ( z?” . . (J33y%’“\c;fr*~ ACECIQ‘ImEDC 3113115 The author wishes to express his gratitude to Dr. Lverett H. Everson and Dr. Gordon 3. Guyer for their guidance in this study and for their helpful advice in the preparation of the manuscript. Appreciation is extended to Professor Hubert 1. Brown for his help with statistical work and to Dr. Carter K. Harrison for editing the manuscript. The author is very grateful to his wife, Sandy, for her inspiration and encouragement and for the typing of the manuscript. an “I? C 7"!“ 111L3J U; oi...) “L LI 11311111.) SEVIJ-III O O O O O O O O O O O O O O O O O O O O O O O 2 :;&1TERII'JJS A:D l-«LJ Em 1701/15 0 O O O O O O O O O O O O O O O O O O O 0 10 H C\ VQS'JLTSAIDDISCVSSIOL. .0. 00000 0000 o. o. oo o. to \O SEIILT‘RY O O O O O O O O O O 0 O O O O O O O O O O O O O O O O C 8.43 («J t‘ 23' £1) :4 O O O O O O O O O O O O O O O O O O O O O 0 O O O 3—1 1) 1" Q 31. 4 .-H‘ l. 2. 3. LIST OF TABLES 1960 Sprin: Fly Emergence at East Lansing, Iichigan, Grouped Accordinr to Cages With Totals of Jale and Female Flies per Day and Daily Laximun and minimum Temperatures in Degrees Fahrenheit '1 1960 Fall Fly Emergence at Last Lansing, Lichigan, Grouped According to Cages with Totals of hale and Female Flies per Day and Daily Laximum and Minimum Temperatures in Degrees Fahrenheit Synoptic List and Number of Insects Removed from Traps from April 27 to hay 22, 1960, East Lansing, lichigan Randomized Plot Design, Treatments and Planting Dates in the East Lansing Experiment . . Number of Larvae oer Plot in Fall from 50 Plants; Number of Larvae per Plot in Spring from 50 Tillers; Yield in Bushels per Acre from the Plots and Treat- {fientSooooooooooooooo Analysis of Variance for Spring Larval Count of Fifty Tillers per Plot . . . . . . . . . Analysis of Variance for Fall Stand Counts from Three Foot Lengths per Plot . . . . . . . iv 17 22 29 31 33 3h 3? u n o I v n . q FI «1 rs a LIPS. l. 2. 3. LIST OF FIGURES S A Photograph Showing the Type of letal Cage Used in TrappingFlieS..................... A Photograph Showing the Type of Canvas Covered Cage USGdinTI‘aplfdnijlieS 0000000000000... haximum and fiinimum Daily Temperatures in the Spring and the dumber of Hessian Flies'uhich Emerged per Dayoooooo00000000000000.0000. haximum and Minimum Daily Tenperatures in the Fall and the Number of Hessian Flies Uhic Emerged per Day . . . ar CranhsS Showing Outside air Teate eratures, Teznf>eraturesv Inside Canvas Covered Traps and Temperatures Inside Metal Traps on October 12,1963, at 8:30 A. M., 1:30 .Il.ar1d5:30P oiLoooooooooooooooooo Daily'haximum Temperatures aid Iunber of Flies Emerging Under Letal and Canvas Covered Traps in the Spring. The Values for the Smaller natal Traps Have Seen multi;alied b‘j 1.2 2 to Conpensate for Their Smaller [greao O O O O O O O O O O O O O O O O O O O O O O O O 0 Daily Lininun Temperatures and Hulber o; Flies Sznerr; in: Under Letal and Laivas Cove red Travs in the To il. The Values for the Sualler getal 2ra_:s have Seen Lultiplied by 1.22 to Compensate for Their Smaller Area . . . . . ll 19 2h 25 27 ABSTRACT The fall and spring emergence patterns of Hessian fly at East Lansing, Eichiran, were studied by a daily collection of flies emerfing from wheat stubble into metal and canvas covered traps. The temneratures were higher in the metal traps and significantly more flies emerjed under the canvas than the metal traps. Studies were made on control of the Hessian fly with a systemic insecticide. Seed treatment and granular applications were used in the fall and granules were broadcast in the spring when the wheat was topdressed. Fly was controlled with fall treatments but no in- crease in wheat yield was obtained. There was no significant control nor increase in yield with the Spring application. T‘ T ‘ vvr‘p‘q- 1.9 .5.u.n.u.CDvV.o..LL-. The hessian fly, broujht into this country in 1773, h;s oe en one of the most serious insect pests of soft wheat. Attempts to control the fly, by use of sprays and dusts, have been unsuccessful. PrOper cul aural netnods offer some means of control for the fall but not the spring brood. Attention of xperi13ntars has recentlv turned to ngstm insecticides applied, either at planting time as a seed treatment or a g anular in-row treatment, for the control of the larvae. 1 The insecticide is assoriei 3y the root sys tem and transloca .ted throuyhout the plant, rendering it toxic to sap feeding insects. This study was unc ertal :en (1) to study the emergence pattern and bioley'of the fly ii the srri1: 31c fall; (2) to dete eznine the effective:1ess of a S"st3.1ic insecticide for the control 01 spring cnd 1 all larv 1 populations; (3) to conpare the effects of seed treatment and granular in—row applicatio 3n; and (L) to deternine the effect of treatment on vi: or stanc and Yield of wheat. ) . In an historical review, Osborn (1:) states that the first distinctiV3 cannon name given to the insect inilictini danare on the wheat crows early in the history of this country (1773 was "”essian fly". Te further reports that the first scientific _' . r r .. ~ .7 V?" \I-xh :3— ‘qJ- ' qr: -. T y " ' , ion ane nane, Fldtjffimfa oestruCtor, was given OJ Say in 1317. The scientific name is an indication of the type of injury. ice rdin~ to wtlton and Packard (23) this was the nest injuriou insect known to winter wheat an; the annual damage was estimated "- 1 I \/—.- r‘ r11. A m j ,, _; _~_ , ~r Hf" .1. '1 - "."'- ’ -1 c at ,iJQ,uud,OJd. he losses Lug to tie “CooluJ fly in huJSuS in 1927 were estimated at 23,000,000 bus els. ,. - _ :1 .. i - , 1.1 '1 , , , , A " e ”s in use iarrons on tne defer S116 o- ens lo a: leax3s c1 Une ‘fi 1 ~‘1-L ' "'. J- r: N T '1 """" n v— -‘ \ r~ I 4.» q I -»r. o vixr - 4" L‘ a. « r'\ .J.‘.Gc. u plalu (5.x; d511c~ilj new/Col 08 c. law :9 11133143: 0.1. Snail on u ~: ~ -. ‘. T n ' “ -a .‘a 5"" - .' ' ‘ n, ‘I "vv-r‘ ‘ - at 81.1 le slate. ...nen the e. .0 hatch in about 1131.11“ dado, t 1e 33111;. V larvae crawl dew; between the sheath anc the base of the sheath. This position is usually bel w the ground in winter wheat and just above the first or econd joint in Spring wheat. T1e larvae remain in this position for about three weeks during which time they continue to feed. The larvae then shortens and shrinks away from its old skin which fo~ns a puparium, or 'Elaxseed", withi. which it remains in a quiescent stage for a varying lenjth of tine denendin: ufon climatic conditions. The larvae changes into a pupa within the flaxseed and in time, dependent on climatic conditions of temperature and moisture, the pupa forces Open the puparium, works its way out and up the sheath to the open where the adult emerges. There may be several broods in a year depeidin: upon climatic conditions. Hutson (13) in lth reported that the generations causing the most danaqe were the fall and spring generations. He further stated that the damaje was caused by he larva of the fly which feeds beneath the leaf sheath just above the lowest node on the plant. The larvae feed by scrapinfi the plant tissues and sucking up plant juices resulting in lodginf and shrivcling of the heads f the injured plants. hill and Smith (9) reported in 19L3 that the reduction in yield was directly related to the percentage of culms infested and the number of puparia per culm. The loss ranged from .Oh bushel per acre when 1% of the productive culms were infested to 15.? bushels when 100% of the culms were infested. These losses do not include those resulting from lodging and shattering caused by the Hessian fly. Until 1957 the attempted control of the fly was mainly by cultural measures. Jalton and Packard (23) in 1930 stated that cultural measures, the objectives of which were largely preventative, were: (1) keeping the pest from attackini young wheat in the fall, and (2) increasing the vifor of young plants in order to enable them to counteract the insects' effect. The practices employed 11‘ were: (1) late sow'n: after fly-free dates, rotation of crops, plowinfi under of stubble and destruction of volunteer wheat, and (2) enrichment of soil, thorourh preparation of the soil and proner sowing of the best seed. They state that the reason for late sowing was that most of the adult flies had emerged and died by the time the fly—free date occurred, and thus, there were not many flies present to lay eggs for the spring brood. Brown (h) made the first report in 1357 of a successful systemic insecticidal control of the Hessian fly. He used phorate (thimet), a systemic insecticide in a hhj formulation of carhon, used as a granule. Gifford et al. (7) state that the chemical nomenclature of phorate is 0,0-diethyl S-(ethylthio) methyl phosphorodithioate. According to Bennet (3) a systenic insecticide is defined as a substance which is absorbed and translocated to other parts of the plant, thus rendering untreated areas insecticidal. He further reports that work on systemic insecticides was begun in 19L? by Schrader who found that many types of compounds exhibited insecticidal properties but that phOSphorus base compounds were the most satisfactory. Wilson et al. (26) reported in 1960 that phorate applied in th fall controlled both Hessian fly and aphids with a seed treatment of 0.5 pound phorate per 100 pounds of seed. The spring brood of Hessian flies was controlled by granulated 103 phorate broadcast at the rate of 1.75 pounds of toxicant per acre in early April. They further reported that highly significant increases in yield were obtained with all treatments. Brovn (5) reported in l)60 that a one pound rate of phorate and disyston applied as granules at seeding time gave excellent control of the Hessian fly for the fall period of growth of the wheat and that the grain yields were signif- icantly hither. however, he reported no significant increase in grain yield when the seed was treated. Guyer et al. (8) reported a significant reduction in stand in 1960 as a result of seed treat- ment with one pound of phorate. They also reported an indication of reduction in infestation both as percent plants infested and insects per 100 plants by seed treatment with 0.5 to 1 pound phorate per acre. Systemic insecticides have been used on crOps other than wheat and their insecticidal effectiveness has been very promising. Paranoia et al. (19), workinr with Bayer 19639 and phorate on cotton, found that fleahopper infestation, cotton aphids and thrips were all controlled for about four weeks. Ashdown and Cordner (2) reported that seed treatment of peas with 0-2-ethylmercaptoethyl 0,0 diethy - thiophosphate gave effective control of pea aphid for 80 days. Ivy et al. (1h) found that cotton treated with phorate at high rates controlled boll weevil. Xetcalf et al. (17) found that dithio-systox and phorate were good for treatment of flax, alfalfa and other agricultural crops to protect the newly emerged seedlings against the attacks of mites, aphids, thrips, whiteflies and caterpillars. Wilcox and Howland (25) working with phorate systemic sprays found no phytotoxicitv on strawberries, lima beans and swiss chard. According to McColloch (16), in 1923, the natural dissemination of the Hessian fly takes place by fliiht in the adult stage. The fact that migration does occur has long been recognized. He listed several early authors who mentioned the fact that the fly may be carried limited distances by the wind. He reported, however, that flies may be carried from two to five miles by wind without apparent injury. LcColloch also stated that the size of the pepulation of the Hessian fly is dependent to a larce degree on the influences of climatic conditions, most important of which are temoerature and moisture. The fly is most affected by these factors in the adult, egg and first larval stage; while in the second larval and flaxseed stages it is quite resistant to temperature changes. He states this axiom, "Those conditions most favorable to the growing of wheat are also most favorable to the develOpment of the fly, and conversely, conditions adverse to the growth of wheat are adverse to the devel- Opment of the fly". Halton and Packard (23) in 1930 reported that the adult flies lived only a few days, the period depending somewhat upon temperature conditions, frosts and the activities of the flies in the fall. They also reported that egg laying, development of the young maggots and emergence of flies from the pupal stage are retarded by low temper- ature. Freedom of late sown wheat from attack by the fly may be due largely to the fact that most of the adult flies are dead by the time of sowing. They reported furtner that the best average safe dates for sowing in most states have been determined from a series of sowincs on different dates. Hopkins (11) in 1919 stated: "When the averare fly—free date, as determined by debster for Wooster, Ohio, is taken as a basis for computing corresponding ly—free date constants for any other locality within the entire refiion of winter wh at culture in the United States, and when it has been compared with the average dates that have been found in actual practice to be safe, the earlier or later departure from the constants are found to be within the range of error and the departure due to regional, local and seasonal influences. It is also found that the general influences and general intensity of these influences can be determined by further investigations and so measured in terms of time that computed constants can be corrected for any locality so as to be close enough to the actual for all practical purposes". He also said: "Other things being equal, variation is at the rate of four days for each degree of latitude, five degrees of longitude and h00 feet of altitude". he stated that the basis for determining the average fly-free date for winter wheat growing areas is the data taken at‘WOOSter, Ohio, and the variation taken as stated above. Webster (2h) reported in 1d99 hat he determined the fly-free date for fiooster, Ohio, by planting wheat at different dates at five-day intervals for several years and then observing which planting was free from fly infestation. HeColloch (16) stated in 1925 that the study of the Hessian fly and its control was influenced by many factors, such as wheat acreage, aéricultural practices, varieties of wheat and climatic conditions. He listed three main limitations of the fly—free date as: (l) The fly-free date only protects wheat from the main fall brood. Since it does not strike at the source of infestation, it offers no protection from supplementary fall broods or the two spring broods. (2) No brood is complete since all the flaxseeds do not produce adults at the same time, but some always hold over. (3) Time of planting is an important factor in wheat production. It influences tillering, winter killing, maturity, yield and quality of the grain. Hopkins (10) stated in l)00 that periods of abundance of the fly vary with latitude and altitude. The beginning or ending of a period varies with the season, the weather and local physical conditions, such as exposure and character of the soil. A wet August and September may cause an early disappearance of the fly while a protracted fall drouth and warm weather may cause a later disappearance. Also, a lirht, sandy, warm soil may delay the fly disappearance for a few days, whereas a heavy, wet, clay soil may cause earlier disappearance. Further, a northern exposure will give an earlier disappearance and a southern exposure a later disappearance. Hopkins (12), writing in 1933 on bioclinatics, stated the relation of temperature to the retariation of life activities. "Above a given effective temperature, life activities are accelerated up to a critical maximum, above which the ey are retarded, and below a given tempera ture the activities are retw ei to a critical minimum when activities cease or the organism is killed. The zero of optimum or Wiective teiae rature varies wi-tn dii fe nt s>ecies and even varieties of the same species. The zero of effective temperature is in general between LOO and 309?. with an Optimum at about 50° to 60°. Thus we expect that retardation would increase below L30 and that acceleration would increase above L30 to about TSOF., when retardation would be more or less evident up to 33° or more." He further stated: "The minimum for the Zh-hour period, for a period of days, is as a rule representative of more hours of low temperature and retarding influence th an of' hifh temoe atw an d accelerating influence". The work of Hopkins on bioclimatics ani the effect of temperature and its variations with latitude and loncitude has served as the basis for figuring fly-free dates. Allee et al. (1) stated that the rate of living adult organisms, speed of embryonic, larval or pupal development and other behavioris tic reactions we; 8 all accelerated by higher temperatures. This affected such important ecological phenomena as tin e span of tr e life history or len;th of any given stage. They further stated that the results of modern ecological summation of temperature developed from the extended experience of the phenolor ists were that the accumulation of a given daily excess of temperature above some convenient base will approximately coincide with the completion of a fiven state in the development. TniI -LS AND IET"QDS The emergence pattern of the Hessian fly was studied in the field by daily trapping of the flies w liCh emerfei from ti‘ie s Huible. The cafes were of two types: one of sheet metal and the other wood and screen covered with canvas. The metal cages (figure 1) were cone 3: lap ed and in two sizes, the larger ones covering 1,320 nd the smaller ones, 706 square inches. The tops of the cones had oeen cut out and fit+ ed so that wide mouthed mason jars could be inverted and screwed into them. An inverted paper cup without the bottom (Dixie Fountain Cup - six ounce - number 7026) was placed inside the mouth of each jar. This was fastened to the inside of the mouth by tape. The flies would fly up through the bottom of the cup into the jar toward the light and remain in the jar. The wooden frame, canvas covered cases (fi: ure 2) were constructed from 1 by 2 inch hardwood. They'were pyramid shaped and covered an area of one square yard or 1,296 square inches. The teps of the upri hts were held to:ether ov a 5 inch square piece 01 B/L inch pl; .vood in w.ic ch a hole had been cut so the mouth of a regular quart mason jar would fit snuxly into it. The frame was first covered with 20 mesh plastic Saran screen, but it was soon found that the insects would not fly up into the bottle traps but were attracted to the light enterinr throuqh the mesh sides. The cages were then covered with canvas to exclude the lirht around the sides so the flies would be attracted to the light which came in through the 10 ll ”W# "u. '. t“ L fl. 1, "was. . In In", P " run "A J : v‘.n_-_' , rlgUTO l u .JObOd a?“ buouiig “no -hjc oi Metal cave coed in Ira, inj :lies {ifure 2 A Photograjh Sh win: the Tyre of Canvas Covered Cafe Use” in Trapping Flies 12 bottle at the top. The cups which were cut and placed inverted in V the mouth of tne regular quart mason jars were Lily Cold Drink Cups, m1 Number 67, tall waxed. inese traps worked on the same principle as the metal ones. Location and Collection On April lb, 1960, as soon as the snow left the ground, the cages were placed at random in a wheat stubble field for spring collection, except for case 13 which was in a wheat field which had been planted in the fall. Soil was packed around the base of the cages to prevent escape of the insects. In late August the cages were moved to an adjacent field of new stubble which had had a sprin: infestation of hessian flies. Both fields were located on *— the hichiqan State University Farm at Easl L“nsin3, Iichiéan, and l. were protected bv woods on the south and west sides, the direction (.4 ('0‘ of he prevailin: winds. Daily collections of flies were made in the Spring from late April when the snow left the ground until late Lay and in the fall from early to late September after which there was a hard frost and no flies were obtained. Empty bottles were put on the traps every day in the late afternoon and the ones containing flies were taken into the laboratory where the flies were killed with carbon tetrachloride, the count recorded and the insects mounted on small paper triangles with clear fingernail polish. The flies were l3 counted with respect to sex and the count of each cage was kept separately. Leasurenent of Temperature \ The temperature inside and outside tne cages was measured three times. In one case, two recording thernographs were used, one being placed inside the cape and the other out ide for a three day period. Temperatures were tak n twice at 3:30 A.L., 1:30 P.£. and 5:30 P.1. usinj a Leeds & Northrup Potientioneter. The maximum and minimum temperatures were obtained fron Climatolorical Data for hichigan. Fall Treatments Phorate was aiulied at East Lansinc in two wa's: l as a _- a 3 seed treatment at .25 pound active inrredient per 100 pounds of seed and (2) as a S; cranular insecticide applied with the fertilizer at one pound active ingredient per acre. The experiment consisted of six plots which were replicated three times. The treatments were as follows: 1. Untreated - planted.Au;ust 31, 1959 2. Untreated - planted September 8, 1959 3. Seed treatnent at .25 pound active phorate per 100 pounds Seed - planted September 3, 1959 h. Phorate St granular with fertilizer at 1 pound active phorate per acre - planted September 3, 1959 1h 5. Seed treatment at .25 pound active phorate per 100 pounds seed - planted September 21, 1959 6. Untreated - planted September 21, 1959 Each plot was 50 feet long and 7 feet wide. Genesee, the Hessian fly susceptible wheat variety used in this experiment, was sown at the rate of six peeks per acre with a John Deere ll hole drill. A 5-20-20 fertilizer was applied at planting at the rate of L50 pounds per acre. Yields were taken from a four foot strip down the center of each plot and harvested with a Jari mower. Spring Treatment In the spring of 1963 an experiment was conducted in Cass County in southern hichigan on the Norman Harvey farm, Jones, hichifan, to determine the effect of a spring application of phorate with nitrOjen topdressing on the yield of wheat and the population of the fly. The test on Genesee wheat consisted of six treatments replicated four times, the plots being 8 by 25 feet in size. The treatments were: 1. Control 2. hitro;en at 30 pounds — phorate at 0 pounds per acre 3. Nitrocen at 0 pounds - phorate at 1 pound per acre h. Hitr03en at 30 pounds - phorate at 1 pound per acre 5. HitrOfen at 0 pounds - phorate at 2 pounds per acre 6. HitrOjen at 30 pounds - phorate at 2 pounds per acre 15 Both nitrogen and phorate were applied with a b foot hand Operated Sandy applicator on April 20, 1960. fields were taken from h by 10 foot strips and the grain was hand harvested due to heavy lodging. Fly POpulation The fly pepulation in the fall at both East Lansing and Cass County was measured in the following manner. Fifty plants were dug at random from each plot. The numbers of larvae or flaxseeds found per plant and per plot were tak n as a measure of the population and, hence, the effectiveness of the treatment. rmhfl 1.5:)4. h In the spring, 50 tillers were used as a sa - instead of 53 plants. RESULTS AKD DISCUSSION The spring and fall broods of the Hessian fly were studied in 1960 in an effort to determine the periods of emergence of the fly under Iichigan conditions and the best time to apply systemic insecticides. The emergence of the adults began in the spring on April 28 and continued through Lay 22 as shown in table 1. The dessian flies collected the first five day were not recorded by cage number but on the basis of the number of males and females. Beginning on may 3 the emergence recordings were by cage nunber. The collections were - terminated on day 22 because there was a constant decrease in energence even though the temperature at this time was high, indicating that most of the flies from the spring brood had emerged. The emergence of the flies was correlated with the temperatures of the day and night previous to the dates of collection since the flies emerged early in the morning as reported by McColloch (15). Figure 3 compares the daily maximum and minimum spring temperatures and the rate of emergence. The rise and fall of the curves for fly emergence follows the maximum temperature on a one day delayed action basis and also corresponds with the minimum temperature on the day of collect’on. This is because temperatures are reported on a 2h hour basis from 12 midnight to 12 midnight and thus the maximum temperature was reached the day previous to emergence and the minim‘m temperature the day of emerjence. The correlation l6 l7 H H H N a H H m H H onm m H J N H H H N mHmEmm m H H H m m H H onu w H H q H H mHmeom N H p N m m m H H H H mHmm N H m m N H m H H a H mHQEmm H N H H N a HH H H H meu e H m N m H onnmm m H N N H H 0H5 m 4 H N H N a H mHmemm N m N N a H mHme H N H N H N mHNEmm H H H H H w H N onm m H N H m H N N N H onEmm m m N H e N m H N N mHmm N H H N mHmeom m H N H mee H oHMEmm NN HN oN NH mH NH 6H mH :H mH NH HH 0H m m N w m a m mommo N H on mm m m N ewe HH.H H pngcmazwm mmmummo CH mmAZPmpmmnma ezeHch cam Esewaa mHHmQ use hon pom mmHHm mHQEmm pew mHmu mo mHmpoe spHB mmmwo 0p NcHwaoood Ummsopm «cmeonn .chmcmH pmem pm monompoem hHm mcHndm opmH H mHnme mm Nm mm mm m4 mm H; H: 3 mm mm NM NM pm Hm N: am Hm 3 H3 NM Nm. m: N: mm .NH momflwmm manpmpooeme mBSHcHH 18 Ne NN NN NN NN oN mN NN me am «N NN NN N4 N: No mN NN NN NN Ne em HN 9N Hw .m mmmetem myopmhooEoB GSEHNdx NH N HN NN 4N He me me NN a o o H H NH N N; oN NH NH N m N m N HNHHV HNNON peeps N N NH NN NH NJ Nm Nm NH 4 o o H H N N HN NH N a o o m H H HmoNv mmHNH HNpON H H a NH NH NH NH N N m o o o o m H HN N N N N m N N H HNmHV mOHNaoN HNHON H H one NH mHNEmm a N m H N oHNHH NH H H N H mHmEmNH H NNNHHN NHHN mHmuHH N N N m H H H H H N mHNamN N N m NH m H N N m H mHNm OH H m : mHmEom NN HN oN NH NH NH NH mH NH NH NH HH OH m N N o m H N N H on NN NN mmNmo Nae Head Umschcoo H powH ‘3 Temp. to \fl. 30 (D m l -r-' 60 . 5 \fL km 10 \J‘L 1 Dai ly Maxi mum Tame ra ture __ _ _ _ Daily Ilinimun Temperature .. Daily Fly Emergence Figure 3 I:fa::imum and Minimum Daily Temperatures in the Spring and the Number of Hessian Flies which Emerged per Day. 2O coefficient for the maximum temperature and rate of emergence was .577 which was highly siynificant while the r value for minimum tenperature and rate of emergence was .Bhl which did not indicate significance. The degrees of freedom were 23. The term "heat units" used in this paper signifies an amount of temperature above a certain point. This point was not determined because the hourly, daily tempo asare was not available. Aoparent y, the pupa must have a sufficient number of heat units per given time before the adult will emerge. The highly significant correlation between I the maximum temperature and emerfence does not nean that the maximum temperature of the previous day furnished the total number of heat units necessary for emergence but that it added to the accumulated units enouyh heat units to allow emergence of the adult, if other conditions, biological and environmeztal, were satisfactory. The r values for the fall emergence correlated with the maximum and minimum temperatures were -.153 and .h26, respectively. The minimum temperature-emergence coefficient of .LZS was sieiificant a the 5} level. This is the reverse of the Spring data. It would appear that the daily Nilldli, fall temperature is important in indicatin: a break in the prJ-pupal stage of the insect. It is not known whether this is due to a summation of units as in the spring or the temperature dronpinj below a certain point. It would thus appear that Hessian fly enerrence in the soring Kl ‘ PI is governed by the amount of heat or heat units the ilies receive; 21 whereas in the fall, mininum temperatures are imyortant in determining the date of eme hence. it Last Lansing the flies in the fall brood began emerging into the traps on Septenber 11 and continued emerging until September 23, as shown in table 2. tn the nifht Ol Seatenher 2?, there was a heavy frost and no flies were colle ted after tnls date. Figure b shows that the peak emerfence period was from September 13 to September 21. Continued emerfence of the flies until September 23 was not erected as the fl“ .te for In;han County‘was September 17 to 19. :OWBVJT, the continued emergence could have been due to the warm dry fall or the cafe efLect. . f" 10 detehnine whether the late emerrence of flies into the trans was due to a care effect and, to compare the two tyres of CCTBS as to temperature and fly emergence, tenreratures were taken both inside and outsio th cages an; the difference in the number of flies emerging was recorded. The metal cages exhibited greater tenoerature hanges. They warmed up faster in the morning, were hotter at noon and cooled off quicker than lid the cloth cages. Drring the day 'he temperatures inside both tjfies of cages were considerably higher tnan outside. Ls seen in figure 5, on October 12, the outside temperature was 75°F. at 1:30 P.L. while at the same time it was 92° 1 ‘30 an in tie cloth cages 834 10) in the metal cages. Readings taken Turin; 1_ 1.‘ .3. J. . .1- :1 i1- ..-,,,- 1, ... -1 .' n .— .1. ,,.- ..1 ." a" . . _ tne JOLUGSU pare oi one sutie~ SHOHCU Si ilar ten,erauire uiiierences between the metal case, 010th Cage and outside. H N H N H N H N N H N OHNA m H H H H H m m N mHmsmm H H H H N H N m H H H H NHHN. m H H H N H N m J H m H a m N meEmh N N H H H N N N H mem N N m H N H N meEom H N N H N N N N m N NH? 0 N m N H N m H N N mHmEmm H H H H N H H H 33 m H N N H N N m N N N H m oHEmN H H H H H onm H H N H H m N H H H H H onEmm N N N m H H H NHHN.“M m H a m m a H mHmEmm N H N H N H H mHmm N H H N N H m N N H mHmEmm H H N wme H H H H H H mHmsmm mN NN wN mN :N MN NN HN ON mH mH NH @H mH :H MH NH HH mmmmo umpzopmmm pHm£thgmm mmmnumn :H mdepmpomEmm ESEHCHH vcm Engxdm hHHwQ flaw hma pom mmHHm mHmEmm van meu we mepoa HPHE momma op LCHUHoood vmmsopm acmmH:0Hm .MCHmcwH pmmm pm mocomnmsa.mHm Hme oomH N mHnme OH OH Om Hm mm Nm Om Om Hm mm mm OO HH NH mm Om Om NH .N mmmNNmO mpdpmmeEmB sadfiu ON ON HN NO mm NO ON ON ON NO ON HO mN mN HN Ow HO NN .N mmmpmmo mHSHNNQQEme asemem m H O OH NH NN OH mm mm Hm Nm NH OH NH OH ON mH H HONHV Hmpoe vampm H N N H O NH NH NH mH HH OH OH OH H O NH N N HOmHV mmme Hmpop N H H N HH OH O ON ON ON HN N m N N OH O N ANNHV mmHmsON Hmpoe H H H N H H H mHmH NH H N H H H mHmamN H H H H meH HH H N H H H H mHmsmm H H N N m H N m H H mHma OH H H N H m HH H H N .H H mHmemN ON NN ON mN HN ON NN HN ON NH OH NH OH mH HH OH NH HH mmmmO nmnampmmm UmSCHpcoo N mHan 39 3h 2h O 1 ' V I V T I T Y 10 12 1t 16 13 2o 22 2h 26 2% September Daily laximun Temperature _ __ _ _ _ Daily ‘tinizmm Temperature . Daily Fly Emergence Figure 11 Liaximum and Minimum Daily Temperatures in the Fall and the Number of Hessian Flies Which Emerged per Day. Temp. I—‘ O \J'I 100 95 85 80 75 7O 65 60 1\ E5 C3 1\ E5 (3 IX !5 C. 8:30 A.M. 1:30 P.H. S:°O P.M. A A - Outside Temperature B - Temperature Inside Canvas Covered Trap 0 - Temperature Inside Ietal Trap Figure 5 Bar Graphs Showinc Outsiie Air Temperatures, Temperatures Inside Canvas Covered Traps and Temperatures Inside Ketal Traps on October 12, 1960, at 8:30 A. M., 1:30 P. K. and 5:30 P. M. Figures 6 and 7 comoare the emergence of the flies from the cloth and metal CLjes in the strinj and fall respectively. The total number of ;lies ener~ini in the metal cafes was 113 in the soriny and 136 in the fall. Considering the clooh cages, 233 flies :ed in the spring and 93 in the fall. Even when the dag-to- day flv counts for the smaller metal cages were multiplied by 1.22, to correct for the Staller area covered by the metal cages, the differences, on the average, indicated that more flies emerged under the cloth cages. 3y Love's Z-test for paired values, the numbers of flies emerging under the cloth cages were significantly greater than the numbers of flies emerging under the metal cages. This was probably due to higher temperatures in the metal cages. Therefore it would seem that cloth cages would be the better to use in future studies of this type. The late emergence of the Hessian flies in the traps could have been due to a cage effect. Recording thernOSraphs placed inside and outside the cafes showed that the tclgcratures inside the cafes stayed about 3 to 10 degrees higher than the night temperatures and thus did not yet low enough to effect a break in the pre pupal stage of the insect at the same time as outside. In collecting the Hessian fly, notes were made on other insects found in the traps as they represented insects associated with wheat and wheat stubble directly or indirectly. Table 3 lists the orders and families collected. The predominant insect found in the spring 75 7O 65 55 50 11'; 0 Temp. m. Flies ’J Lu ESBbjéflé’fifiJl'Z Ibf6iBZb§2 April : Hay Daily Maximum Temperature __ __ _ Emergence Under Zletal Traps ............... Emergence Under Canvas Covered Traps Figure 6 Daily Maximum Temperatures and Number of Flies Emerging: Under metal and Canvas Covered Traps in the Spring. The Values for the Smaller Metal Traps Have Been Multiplied by 1.22 to Compensate for Their Smaller Area. Temp. UT. (31).. \71 CA :3 1 [:4 2h : 22 4 2o 4 18 T 16 4 5. I: 1L 4 :1 ' 2 12 J ,' .. l l 10 4 M“: 'x 8 :1 \ ‘ [I M! I 6 a 7 I & , I l )4 1 I", EI’/\I ,' " V 2 , ll 23 1'2 1'21 1'6 1’8 2'0 22 2L 2% 28 September Daily Minimum Temperature _._..___ Emergence Under Eiletal Traps .............. Emergence Under Canvas Covered Traps Figure 7 Daily Iinimum Temperatures and Number of Flies Emerging Under Hetal and Canvas Covered Traps in the Fall. The Values for the Smaller metal Traps Have “een Hultiplied by 1.22 to Compensate for Their Smaller Area. 29 HHNHO mumpaHpopon AHO HNO mepHHsoHe mmpHHspHpHm HNO HOV HHV mmpHpogmHHHmo ompHcOHHsopso mprpHH - AONO Ame HOV HHO mumpcocmEhzop0Hu mepHHhsonpca omUHompmo mmpHEOprcmm Aev WHO Ammv AHO HHV mmpHcOESmCHOH mmeHgnpmm mpepmopHdoHONOH: mmOHHHmCHoooo mmpHpHmm ANNO . HNHHO HHV AHO HOV HHV mmpHCHpmaspcme ompHHpnopHomo mmpHmmHm mepHpoHaHm mmpHHHmpmoHo ompHnmm mumpgocmemm mumngn wpmpmopHmmH mnmpmomHoo whopmoEom mpmpmHEmm emeHHOHH .meHmemH swam .OONH .NN Nae op NN HHaaH.soaH mmwpe scum empoemm mpommcH mo genes; pee pmHH oHpmocmm m mewe 30 was the Hessian fly. Iany other kinds of flies were present, most of which were small and listed as microdiptera. Of the Hymenoptera present, there were 22 Tenthredinidae and also many parasitic HymenOptera listed as microhymenoptera. Other orders found were Lepidoptera (mostly microlepidoptera), ColeOptera, Hemiptera and HomOptera (leathppers). Besides the Hessian fly, the most prevalent insect found in the fall was a fungus net of the family Sciaridae. Along with the study of the biolo;y of the Fessian fly, an evaluation of control of the fly by use of phorate was initiated. Table h gives the plot layout, treatments applied and time of planting for the experiment at East Lansing. Table 5 gives the fall and spring larval count and yield by treatment and replication. By Bartlett's test (20) the variances for the fall fly counts were not homogenous and, hence, all may not be put to;ether for statistical analysis due to the variability between replications. However, treatments 1 and 2 could be put tOgether and analvzed and treatments 3,h,5 and 6 could also be analyzed together and their differences compared. When this was done, the great variability within the treatment 1 replication was still so great that no significant difference could be found. By visual inspection of the fall data in table 5, it would appear that the phorate treatments controlled the Hessian fly. The spring larval count was made after the spring brood had emerged, laid its eggs and the larvae were in the flaxseed stage, (table 6). The "F" test showed significance at the 13 level Reolications [‘3 {N} 31 Table h Randomizc‘ Plot Desirn, Treatments and Planting Dates in the Jast Lansing lxperinent Treatments Border for Infestation 25463! Border for Infestation .h; 03 (1] Tx) ()4 Border for Infestation Border for Infestation Treatment Planting Date Untreated August 31, 1959 Untreated September 3, 1959 Phorate seed treatment .25 pound active phorate per 100 pounds seed Phorate SS granule 1 pound active phorate with fertilizer Phorate seed treatment .23 pound active phorate per 100 pounds seed Tntreated September 21, 1?: September 8, 1))? September 8, 1939 September 21, 1)?) te te L we w. r O 3 . 3 ..3 LU 3 3 d a, ..u v» r K .1. .. _ Q .l \l/ 1*J o, H D On U C h. C J :u be 7/ ,a r“ “/1 \/ 0/ e H) Q J .J .7). 3+ H), V «I, J A. t. )l .x.../ \7 ...u \4/ .l l ”I” 1 A ,_ x l H 1 L u _, , .J C ’ Q l 3 0. «Jean; 3 a 1L vi...“ \. v a 9 a. J at. G ’ 3/ my . A 4ft, 0 T. r r r .— s r n1 r «L S A J. C e o e u r c o an 3 .Q 0 e .3 S to J _ l H... n... n J . 2. S a 3 Q G .1 a A d IL .3 ‘1 u .L 1 1 Au .1 U h A w . Ty .fiU «VJ owl Y),. JV 0 U 3 3 .T... ”A... C _ .3 B t r .u .4 Cu Au .5 L RU Y S. R . e 8 Iv S u... 3 «J z; :u v.4 4U n1. r \u 1.4 6 ml 1H. r v c g G e 3 .3 l G l q. lb l. ;u no is no lo +u wu.wu +u J T n F 3.1 r n n.t 3.1 T Z. lo a «L L c G n a .3 pa e 2 i nu all an all no we. all vi mu all as h, F? P". P5 P? P.‘ flied r *1tre V s." 33 Table 5 Humber of Larvae per Plot in Fall from 50 Plants; Humber of Larvae per Plot in Spring from 50 Tillers; Yield in Bushels per Acre from the Plots and Treatments Treatments - Fall Larval Count Replications l 2 3 h S 6 1 6 h o o o o 2 l2 5 O O O l 3 31 2 O O O 0 an “Eli“‘fifi"__5""_fi_'”—6—""EB" Treatments - Spring Larval Count Replications l 2 3 h S 6 1 L2 DH 26 23 22 39 2 23 15 8 ll 6 18 3 37 L2 2? 16 17 33 nan “UH-“‘Efi“fii“"‘fifi‘“fi§'"'%”' Treatments — Yield in Bushels per Acre Replications 1 2 3 h S 6 1 33-2 37-9 39-? no.2 blob b7-3 2 36.1 L1.§ 1.9 29.8 35.7 32.3 3 36.1 25.3 37.9 26.6 29.5 37.9 Lean " "33.1— — " 179" " ”33.3 "' " '3'279" " "‘33.? " " 3670— 3h Table 6 Analysis of Variance for Spring Larval Count of Fifty Tillers per Plot Iieans of Lhrnber of Larvae per 50 Treatmentsl Tillers per Plot \J'l C.) P) (F t»: (D 0.. 3‘ \f Cf\ h n) ~+4 \ U1 h Planted 9/3/59 Granules 13.7 dF 3.5q, F Treatments _§ 21973 17TOL 3 Planted 9/4/59 Error 10 12.9 Seed Treatment 21 s 3 a 2.37 6 Planted 9/21/39 ’ Control 3 3 = 7.13 3 = 10.h7 2 Planted 9/3/59 Control 33.7 L.S.D. - 53 6.52 13 ' 9.27 1 Planted 3/31/59 Control 3h 1 . . . . Plot treatments and means obtained are arranged in order of increasing size. 2Rance based on Duncan's (6) sisnificant studentized ranges using only the maximum number of means in each table, hence, giving the maximum range needed for significance for level indicated. Any differences or sums of consecutive differences less than the R values are, for sake of simplicity, considered not significant. indicating highly significant differences between treatments. Using Duncan's Multiple Range Test (6), there was no significant difference between the phorate treatments; no significant difference between the controls; but there was a significant difference at least at the 5% level between any phorate treatment and control. In summary, the phorate treatments all differed significantly from the controls :2 demonstrating its effectiveness in controlling the Hessian fly. The fall larval count in table 5 indicated that there was control of the hessian fly by use of phorate and also by late plant- 4 ing. The observation of sicnificantly more larvae in the untreated L J plots than in the treated plots in the spring may be due to the control of the fly in the fall followed by less spring emergence and egg laying and restricted migration or it may indicate a carry- over effect of the phorate. This latter is questionable since Guyer et al. (3) has stated that phorate had no residual effect after 60 days. It was noted in the spring larval count that repli- cations l and 3 had higher pupae count than replication 2. This was probably due to the fact that there were borders along both sides of these replications serving as a source of infestation. Date of planting, treatment applied and anount of infestation had no effect on the yield (table 5) as there was no siénificant difference between the yield of the controls and the treatnents. This is in contrast to the work of Wilson et al. (26) from Indiana where they reported hidhly sifnificant increases in yields obtained ‘where insects were controlled. There was a definite trend in yield, however, increasing from test to east in the plots irrespective of treatments. This appeared to be due to a fertility factor in the soil. Even when this trend had been renoved by adding or subtracting correction factors for the regression line, there was no relation- ship found between the amount of fly infestation and the yield. ”*1 Xeasurenents were also made at East Lansing on height of plants, ‘ disease control and fall stand count in an effort to measure additional effects of the phorate on wheat. 30 significant difference was found t between the controls and treatnents on heijht of plants. There was, [ .E however, some control of nilden and leaf rust. The plants in treated plots appeared darker green in color and were more erect than were 1 ' I 0 those untreated possibly cue to a s imulatory effect on the phdrate. (i The "F" value of stand counts made in mid October (table 7) was highly significant. Duncan's Lultiple Range Test showed a signif— icant decrease in stand count between the early planted treatment on August 31 and all treatments planted thereafter. There was also a significant decrease in stand when planted September 3 rather than Septenber 21. There also was a decrease in stand in the untreated, late planted plots, when compared to the late planted plots treated with phorate. From the data, using Luncan's pultiple Range Test, it could be concluded that the later planting gave better stands and that treatment with phorate increased the stand at all planting dates possibly due to the control of the Hessian fly, disease and T 'vrfi‘h" 37 Table 7 Analysis of Variance for Fall Stand Counts from Three Foot Lengths per Plot Jeans of Three Treatments1 Foot Stand Counts 1 Planted 3/31/59 Control 21 2 Planted 9/3/59 Control ,A A~ J F F? i 1 U) ,0 O Treatments —3' 2o . o h Planted 9/3/52 Error 5 2.86 Granules 32 S E = 3 Planted 9/q/39 , Seed Treatment 30 R. - 53 = 13 = e Planted 9/21/39 Control at L.S.D. - 53 = 13 = S Planted 9/21/59 Seed Treatment Sh lPlot treatments and means obtained are arranged in order increasing magnitude of stand count. of other insects. It would appear that either phorate seed treatment is not as toxic to the plant as is the heavier application of the granular yhorate or that it controls the fly better and thus reduces loss of plants due to the feeding of the fly larvae. In the spring of 1950, an experiment was conducted in Cass County to determine the effect of tOpdressinq the wneat with nitrOgen and 'F‘ phorate in an effort to combine both operations and to see whether or not a spring application of the systemic insecticide would control the spring brood of the fly. ' t. Several factors enter into the results of a spring application $7“ of granular phorate. (l) The application must be followed by rain to leach the nhorate into the soil so it is availahle to the plant; and (2) this application must be timed so the plant can take the phorate into the roots and translocate it throujhout the plant before the fly fl larvae feeds. It now appears that tn (3 fly larvae feeds on the wheat for only 5 or 6 days followinfi the e53 hatch (Gallun, personal communication). A combination of factors are therefore required for optimum results. In the Cass County experiment, the time of emergence of the fly was not :nown. Only one application of the treatment was made due to a late spring. There was no rain for seven days after treatment. Thus, it is not known whether the insecticide was applied early enough or if lack of rain was the cause, but the results did not indicate a significant difference between the control and the treatment in either total number of larvae, percentage of infested tillers or yield. SUV. .2 :x'uv _., This study was initiated to ascertain the emergence pa ter rn of the Xessian fly in the fall and spring and to evaluate the effective- ness of pho orate a_p1ied in the fall and spring to control the larval population of the Nessian fly. The emergence of he fly in the fall began on September ll, 1960, reached a peak on September 20 and ceased on September 23, 1960. In the spring the flies began emerging on April 25, 1960, reached a peak on Kay 17 and collections were terninated on Kay 22. Correlations between fall emerfence and tenoeratures indicated that minimum temperatures were important in re ulating fall emerrence whereas in sprinc maximun temperatures were in‘L or nt in re"llatln~ emergence. The temperatures and numbero f flies energing into :netal and 010 uh traps \ere compared. Lhe results showed higher tenleratures in the metal traps t an in the cloth traps and also sifnificantly fewer flies emerging into metal traps than the cloth traps. his study indicated that pho~ate was effective in controlling larval population in the fall. There 1% s also a redlction of the spring orood of larvae in the fall treated plo as but no increase in yield was found over the untreated plots. The spring ap;lication of the insecticide had no significant effect in controlling the larval population. 39 to Stand counts taken in mid October showed increases in stand in the plots treated with phorate over the untreated plots at all dates and an increase in stand with late planting. ‘vII‘ - ' .v“ - . ! . . u g nt‘dll’..lv:i'trnfl ' - r .ii-ifl . I--- ll... 1. 6. 7. 8. 9. 10. ll. 12. BIBLIOSRaPHY Allee, W. C., Emerson, a. 3., Park, Orlando, Park, Thomas, and Schmidt, K. P. Principles of animal ecol gy. Heat, W. B. Saunders Co. Philadelphia and London. pp. 91—120. l9h9. Ashdown, D., and.Cordner, i. 8. Effects on insect control and plant response of a systemic insecticide applied as a spray, a seed treatnent or a soil treatment. Jour. Econ. Entomol. hsz3o2-3o7. 1952. F“ 1 Bennet, S. F. The behavior of systemic insecticides applied to g ' plants. Ann. Rev. of Ent. 2:279-296. 1957. g Brown, H. E. hessian fly control with systemic insecticides. F. A. 00 Plant PI'OteCtion 31110 531249-1550 1957. Insecticidal control of the Hessian fly. Jour. 4 .‘SCOn O EHtOILlOl o 53 3501-503 0 l)60 o H Duncan, D. B. Multiple range and multiple F tests. Biometrics. 11:1-t2. 1955. Gifford, J. R., Buckhardt, C. C., and Somsen, H. W. Effects of thimet and various stickers on germination and seedling growth of wheat. Jour. Econ. Entomol. 52:650-65h. 1959. Guyer, G. 3., Brown, H. M., and wells, Arthur. An evaluation of systemic insecticides for control of Hessian fly in Richigan. Iichigan State Agr. Exp. Sta. Quarterly Bul. h0:595-602. 1958. Hill, C. C., and Smith, H. D. The relation of Hessian fly damage to yield. Jour. Econ. Entomol. 13:69-73. 1925. HOpRins, A. D. The Kessian fly in West Virginia and how to prevent losses from its ravages. Jest Virginia Agr. Exp. Sta-o BU]... 670 19000 The bioclimatic law as applied to entomolo;ical research and farm Practice. Sci. Lonthly. Szh96—513. 1919. Bioclimatics, a science of life and climate relations. U. S. D. A. Lisc. Pub. 230. 1933. ,.‘|I,l)“lu| V\.,ovul:.‘.‘lrv. u t. z . l‘l. .a | ,r .9 til . . . . x 1“! c .u a. n u > W! ‘ ‘ « ‘ n I! v v . . zkrh fiutson, R. Hessian fly. Iichiran State Col. Ext. Bul. 225. 19h1. Ivy, E. 3., Scales, A. L., and Gorzycki, L. S. A new systemic insectiCide for cotton insects. Jour. Econ. Entomol. ,.J ..r >Ozé9d-699. 1957. McColloch, J. H. The Hessian fly in Kansas. Kansas igr. Exp. 1 n i « oil. 1003. 3‘11 11. 1.923. The Hessian fly problem in Kansas. Jour. Econ. EnJDK-Jiilol C 1v 3 €3.69 0 1225 o . ‘A—JSJ Letcalf, R. L., Fukuto, T. 3., and Larch, R. 8. Plant metabolism of dithio-systox and thimet. Jour. Econ. Entomol. 50:333-3h5. 1997. 4" _ WA ‘flflg‘ 11.... Osborn, H. The Hessian fly in the United States. U. S. D. A. Rule 16 No S. 1893. m; Parencia, 0’ 3°: DaViS: J- No: and Conan, C. B. Control of early season cotton insects with systemic insecticides employed as a seed treatment. Jour. Econ. Entomol. 50:31—39. 1937, Snedecor, G. N. Statistical methods. Collegiate Press, Inc. Ames, Iowa. p. 250. 19h6. Stedman, J. E. The Hessian fly in Hissouri. lissouri Agr. Exp. Sta-o 31110 ‘62. IJOBO . Depart ent of Commerce. Climatolo:ical Data (Licl'gan). 75:53-79, 127-139. 230. Halton,'5. 3., and ackard, C. I. The Hessian fly and how o n 97 A‘ er‘ “a C" " '< 108338 frog]. 1t can be 811.0173.ng do S. D. ..“.o .L'C~r:;Lero :3le lu27o ('vfif‘ ,IJUO ‘ 'Uebster, F. I. The Lessian fly. Onio Apr. pr. Sta. Eul. 107. 1399. Wilcox, J., and Rowland, A. F. Tests with thine on strawberries and turnips. Jour. Econ. Entomol. 53:703-73h. l9>7o Eileen, h. C., Hodges, H. F., Gallun, R. L., and Kirk, R. E. Use of phorate to control aphids and the Hessian fly on winter I. -r-\ '."\ . K (\ wheat. Jour. econ. nntomol. 53:197-200. 19LO. ‘ {i 11,711.941114311! ‘ . V . «3.36.33 . fun”, , nil-cull... , . “Ari, , ., . . lilil; -7 ROOM USE ONLY . 1". ”(tilt Vt. tight! O. it‘v Q I ROOM USE ONLY Pluo“lu- "' ltlfi ..... ‘ullllll ‘ I‘tl‘l‘n .IIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIII IILIII LIIIIII ILLIILIILILIIIIIIIIIIIIIIIIII 312893