'Msrs £33.76 A E32! , a - i . ' -w flit—n" n‘héxfiia I 5 2!. z o 4-: " ' _' :,.Z-u:,,;'/‘vlzj);ow' w..;‘.-;fl.,g,;q ‘. ‘ ' ' , .t_ . . r s .r‘“ b-_:a<-.'-;.;._-- .4-' a; u‘ :5" d O !:~0 .! a“??? £152“? -..- #5 ohm“ t:¢.;.;,§ This is to certify that the thesis entitled THE PHENOLOGY OF DRY BEANS AND THEIR INSECT COMPLEX IN MICHIGAN presented by Alan Saygbeh Gobeh has been accepted towards fulfillment of the requirements for MASTERS degree in ENTOMOLOGY 431/1434? fiL/M/jKQ/g/ Major professor Date_I_’I_&1v 23 . 1986 0-7639 MS U is an Affirmative Action/Equal Opportunity Institution MSU LIBRARIES m ‘— RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. TIDEPEERWOELXSYWDFIIRHFBEJUVS ‘ALHJTTHEHKHNSECHTFESTWCCfldPIID( HNIMHCJIKSAUR By ‘AhmISaygbehl30beh lklflIESES Subnfiuedto hdkmmgniSumelhfivcndgr hipmnkflfbflmunlnncfilherequhenunns fixWhedbgnu30f INLASTIflKCH?SC1Ebfl:E Ikzmrunentoflkuonuflogy 1986 ABSTRACT THE PHENOLOGY OF DRY BEANS AND THEIR INSECT COMPLEX IN MICHIGAN BY AlmSangehGobeh Thisstudywasconductedinthesummersof1984and1985todebrminethe relafimshipoitemperaturemdevebuneMmdpopdafionsdsevaalhseapestsin relation tothedevelopmental stagesotflweirhostfirybe‘ans. DrybeanswereplartethuneatmeMidingtateUriversflyErlomdogy ReseardiFarm,Easthsing,Wdiganandmevaluateiseddevmand powlafionsandplamdevelomem ResultsforthepotatoleafhopperEpoascafabae (Harris)wereanalyzedby regressionoiwmulafivemeanmmbersondegteedayswithabaseofSOOF. These results generally compared favorably with data obtained from a similar work done ten years eariier in Saginaw, Michigan reported by Ruppel and Jennings (1979). Mean imeammbersdallspedescdlededarepMedastaUesandmekanalysesand weatherdataarepresentedasgrapl'sandtables Temperature alone accounted for nearly allofthechangesinthe population ofthe potato leafhopper. Expectedmeanand5%limitsofthe 10%. 50%and 90% population pointspresentedwere generallyoonsistantoverthe study period. Thus fliestudyshowedthattemperatureeenbeusedasaniruexforpredicting seasonal developmentandpoquontrendsoithepotatoleafliopper. 'lhestudyalsopoirrtedom matdrougmandphmopabdafleadwbeandevebpnmunaredmwmalimponanoe toinsects. ACKNOWLEDGEMENTS I wish to express sincere thanks and appreciation to Dr. Robert F. Ruppel for his gentle hand and friendly guidance as my major professor throughout this study. I am also grateful to Dr. Edward Graflus and Dr. Roland Fischer for serving on my guidance committee and for their review and criticism of the manuscript. Thanks are also extended to Mr. Paul Love and Mr. Anthony D'angelo for their assistance and support during the field work of this study and to Mr. John Hayden for his assistance and encouragement throughout the last phase of the study. Thanks are due also to the International Programs of Louisiana State University and University of Missouri - Columbia for the financial support given to complete the Masters program and to the Central Agricultural Research Institute. Liberia for giving me the opportunity for this study. TABLECFCXNTENTS Page USTOFTABI ES . iii USTOFFIGLRES " iv NTRODUCTION . 1 AREVlEWOFTl-E LITERATURE 4 MEN-DDS 8 RESULTS 9 WEATHER . 9 CROPDEVELOPMENT 10 NSECT DEVELOPMENT 12 DISCUSSION - 14 MON 33 APPENDIX 35 LITERATIBECITE) 36 UST OF TABLES Tables Page 1 Julian days, days after planting and 0050 to initiation of growth stages (Lebaron1974)ofdrybeanin 1984and 1985 .............................. 27 2 Mean number of different. stages of some insect pests of dry beans seen at different times during 1984.--. ................. 28 3 Mean number of different stages of some insect pests of drybeansseenatdifferenttimesduring1985-. ................ 29 4 Results of regression of cumulative IDD50 of different stages of the potato leafhoppers on 0050 and the expected mean and 5% limits of the 10%, 50% and 90% points of their populations ......................... 3o 5 Results of regression of cumulative standard damage rating forthepotatoleafhopperadultstDso;1974-. 31 6 Thirty-year mean totals and total rainfall in 1984 and 1985 for East Larsing 32 LIST OF FIGURES Figure Fae 1 Accumulated degree-days with a base of 50 0F at East Lansingafrom June to September of 1984 and 1985 andin ginawforthesameperiodof1974 ................................................................. .16 2 Accumulated rainfall at East Lansing from June to ’ in 1984and 198501..) 17 3 Mean of dry bean plant numbers per 6 row-meters in 1984 and 19.15 18 4 Mean weight of 5 dry bean plants per 6 row-meter in 1984 and 1985 (g) 1 9 5 1”?" of flower numbers per 5 dry bean plants in 1984 and -- 20 6 Mean numberofpodsperSdrybean plants in 1984and 1985 21 7 R ression of cumulative mean insect numbers for tato leglg'qpanynu'stDm; 1984 po -22 8 Regression of cumulative mean insect numbers for potato We on 0050; 1985 2 3 9 R ression of pooled cumulative mean insect numbers for pagan leafhopper nymphs on 0050; 1984 and 1985 ................................................... 24 10 Regression of mean cumulative insect numbers for potato hammered-15mm 1985 75 11 Regression of cumulative mean standard damage rating for potato adults on 0050 at Saginaw; 1974 - - ------ -26 iV INTRCIIJCTUV Haynes et al (1973) have suggested that an alternate approach to the extensive use of chemicals alone as an insurance against serious crop damage caused by insect pests would be to implement a control program which intergrates biological and chemical methods into a crop management system based on predictive pest-crop models. Since the majority of the insect pest pepulations in agricultural systems are keyed to a time-temperature function. temperature has been the most comme used factor in predicting insect emergence and out-breaks. This factor is assumed to have a greater effect on insect development than any other (Edwards, 1964; Chiang, 1978). Waters and Ewing (1976) and Kumar (1984) have suggested that predictive models provide the primary mechanism of information flow to decision and action in pest management, and that the best time at which to treat infestation depends on establishing the relationship between a) the phenology of the plant relative to the life cycle and activity of the insect and b) the seasonal abundance of the insect. On the basis or these and other factors, prediction can be made by a method of thermal summation. Originally based on a thermochemical law, this law states that the quantity of heat involved in a chemical process is the same whether it takes place in one or in several steps, and it is an index for the heat energy required to complete a given stage of development of growth of an animal or plant (Wigglesworth, 1972). Because insects are ectothermic, their development is particularly sensitive to temperature. Extensive research has demonstrated that there is a definite relationship between insect development and seasonal heat accumulation. Within limits the relationship follows a hyperbola. Expressed as rate of development (reciprocal of development over time) ,the relationship follows a slightly curved line 1 which intersects the abscissa at a point indicated as the threshold temperature or base temperature. Only the part of the enviromental temperature above the base temperature promotes development. The amount of heat required for development is expressed in units of 'degree-days' (DD) above the base temperature; 50 0F for most insects (MSU-CES, 1984; 0F are used for all temperatures in this work as 0F is the standard used by US. Weather Stations). A given life stage will normally require a definite amount of heat required (in DD) for completion which may be accumulated in one or several separate steps. The total heat units accumulated to complete a life stage is called the thermal constant for that stage. This phenomenon has been used to predict insect development from field temperatures by temperature summation. Temperature summation has been used in this regard quite extensively for many years. Apple (1952) described a method of following the seasonal development of the European corn borer, Ostrim’a nubifalis (Hubner) by the use of DO. Medler (1952) found that temperature accumulation was a practical method for predicting the hatching date of the meadow spittlebug, Phifaenus spumarius (Linnaeus). Many other investigators (Strong and Apple, 1958; Apple, 1962; Mangat and Apple, 1964; Luckman,1964;Ruppel and Gomulinski, 1969) have used the method of summation to determine the emergence of various pests from hibernation. The Cooperative Crop Monitoring System of Michigan State University is currently using a historical data baseofseasonal pestactivitysummerized inaprogram knownas BIOSCHED (Biological Scheduling) based on DD to help farmers anticipate pest activity before it actually occurs (MSU-CES, 1984). Because the pattern of increase, peak, and decline in insect numbers is determined by the thermal constant needed for completion of the insects' development, seasonal accumulation of effective temperature in the field can provide a basis for predicting insect phenology. Relatively few papers have dealt with the seasonal dynamics of the major pests of dry beans (Phaseolus vulgaris L.) in relation to temperature accumulation in Michigan. The only such study of dry bean pests in Michigan is an inventory of problems, including insects, in dry bean production conducted in 1974 and reported by Anderson (1975). Ruppel and Jennings (1979) reworked the data on the seasonal appearance, based on Julian days, and relative abundance of dry bean insects from that survey. The present study attempts to determine the seasonal appearance of the insect complex on dry beans based on DD and plant stage as predictive indices for use in crop protective strategies. A REVIEW OF THE LITERATURE The influence of temperature on the development of insects was recognized probably as early as the 18th century (Peairs, 1927). In 1736 Reaumer 0n Mangar and Apple, 1964) suggested that the total heat required to produce complete growth of organisms was constant. The first theory put forth with regard to the relationship between temperature and the rate of development of insects was borrowed from botanists (Sanderson, 1910; Uvarov, 1931 ). This was the theory of the “thermal constant" according to which the completion of a given stage in development requires an accumulation of a definite amount of heat energy. By means of meteorological records entomologists would be able to use this phenomenon to predict the time of emergenmce of an insect pest. To accomplish this task, a satisfactory mathematical law relating temperature to the speed of development had to be derived. Several mathematical models have been put forth in this regard. Uvarov (1931) gives a comprehensive review of the literature proceeding 1931 and Wigglesworth (1950) presents an excellent general review of the literature proceeding 1950. ' Many of the earlier investigators (Sanderson, 1913; Peairs, 1927) have arrived at an empirical relation and constructed hyperbolae by plotting the constant temperatures at which insects were raised on the abscissa against the corresponding duration of development on the ordinate. Nearly all the early attempts to derive a quantitative expression to relate temperature and speed centered around the hyperbola and its reciprocal (Andrewartha and Birch, 1954). Davidson (1944) presents an excellent evaluation of the major formulae proceeding 1944. Sanderson and Peairs (1913) credits Peairs for the ”discovery of the significance of the reciprocal of the time involved in any phase of insect growth and the possibility of expressing the velocity of such phenomenon at different temperatures 4 by means of definite index.” Peairs in turn states that Van Oottingen might have been the first to recognize the straight line relation of the coefficient of velocity increase in the rate of growth (Peairs. 1927). Sanderson and Peairs (1913) plotted the reciprocal of the time required for development of several insect species, drew the lines through the observed points and proposed the term ”Developmental Zero" to refer to the points where these lines intersected the abscissa This point has been named "Physiological Zero". ”Critical . Point" and 'l’hreshold of Development” by several investigators (Sanderson, 1913; Uvarov, 1931). “Base Temperature“, introducte by Arnold (1959) is the term in current use and refers to the same point. In its current usage it is generally defined as the temperature at which development begins and below which development ceases. ‘ For many years investigators arbitrarily selected 43 0F as the starting point for development (Simpson. 1903; Quintance, 1905). The base temperature has been shown to vary with species, biotypo, stage of development, diapausing form. and some other environmental factors. However, many investigators (Apple. 1952; Medler, 1955; Strong and Apple, 1958; Matteson and Decker, 1965; Craner et al, 1974) and (Ruppel, 1986) have approximated 50 0F as base temperature for most warm season field crop pests. Simpson (1903) was probably one of the first to develop the concept of the ”thermal constant” expressed in units of “day-degrees" (also degree-days) over a base temperature. Wrgglesworth (1972) summarized its practical value as follows: "...whoro the linear relation between velocity and temperature holds. each developmental process will have a characteristic thermal constant and will require a fixed number of 'degroe—days' to bring to completion. Therefore. even if the temperature is changed in the course of development, it is theoretically possible to predict the time necessary for its completion by adding up the number of degree-days contributed at each temperature. This process is called ‘thermal summation'." The theory of thermal summation implies that the temperature-time curve is a hyperbola and its reciprocal a straight line (Davidson, 1944). Assuming that this empirical description holds true, then the speed of development of an insect under fluctuating temperature within the limits of the favorable range could be accurately determined by linear interpolation on the temperature-development curve. This linear relation between temperature and speed of development has been widely accepted and used as a method for doterrnining the seasonal occurance of certain insect pests. Gleen (1931) used thermal summation as an index to predict the time of appearance of the coding moth, Cycle pomonella (Linnaeus). Headlee (1936) demonstrated this method to determine when codling moth sprays shoud be applied. Apple (1952) proposed a method for following the seasonal development of the European corn borer and developed a working alignment char to predict corn borer damage based on egg or leaf-feeding count on corn of known maturity by this method. Medler (1955) used thermal summation to predict the hatching date of the meadow spittlebug. Strong and Apple (1958) approximated the number of generations of the seedcorn maggot, Delia platura (Meigen), to closely agree with the observed number in the field using thermal summation. Apple (1962) showed that relating light trap catches of the European corn borer and the corn oarworm, Holiothis zea (Boddie), to temperature accumulation provided a means of forcasting larval populations in sweet corn. Mangart and Apple (1964) and Luckrnan (1964) used a similar approach as a method for determining the timing of corn oarworm insecticidal treatement. Ruppel and Gomulinski (I969) suggested the computation of DD with a base of 50 0F as an index for starting field surveys for the cereal leaf beetle, Oulema melanopus (Linnaeus). Work by several investigators have shown that the temperature-development curve is curvilinear over a wide range of temperatures and linear only over a narow range. The procedure followed in the classical method of temperature summation has undergone some modifications to take into account the curvature of the graph. Davidson (1944) suggested the use of the logistic equation in place of the hyperbola. Ruppel (1975) showed the feeding-temperature activity of insects to fit this model. He has also used this model to describe the emergence from ovorwintering quarters, seasonal increase and diurnal trapping of insects (personal communication). Ruppel (1986, Dept. Ent., Michigan State Univ. unpublished) showed that the expected time of development at a given temperature can be calculated from the regression of logistit of the time of development on temperature. To facilitate such calculation Ruppel and Dimoff (1978) computed tabular values for the logistic curve. It can readily be seen that ample evidence exists to support the hypothesis that the pattern of increase, peak and decline in insect numbers over a season appears to be determined by the thermal constant needed for completion of the insect development. Gleen (1931) summed up the value of this phenomenon as follows: ”Accumulative temperatures based on atrnosphotic conditions cannot be depended upon to indicate when insects which hibernate under ground will emerge from hibernation, but for many insects that spend their entire lives in the open, the same temperature units of effective day-degrees as have been worked out may be found accurate enough for ordinary forecasting”. . The use of DO to predict development of crop plants has been limited. Smucker of al (1978) use a base temperature of 50 0F and noted that a total of about 1800 0050 are needed for the maturation of dry beans. Lebaron (1974) based the developmental stages of dry beans on the average days from planting, however, and not on DD. He also notes that plant size (as internode length) is dependent on environmental conditions and is independent of growth stage. Smucker (1978) notes that water (rainfall, relative humidity, evaporation) and solar radiation are important to dry bean production. The effects of those parameters on insect development through their effect on the plant have not been examined. MEN-Km Certified seed of the dry bean (Phaseolus vulgaris L.) variety Seafarer obtained from the Michigan Crop Development Association was planted in an area of 100 X 50 m. at the Michigan State University Dept of Entomology Research Farm, East Lansing, Michigan. Planting date was 4th June in 1984 and 5th June in 1985. The seeds were ' planted with a unit planter with a 5 cm. spacing in 60 cm. rows. The herbicides Treflan at 584 ml/ha was applied pre-plant-incorporated and Amiben at 9.35 I/ha was applied pro-emergence both years. Fertilizer was applied at planting at 504 kg/ha 0' 8-32-16% in 1984 and the same amount of 0-10-20% in 1985. Theareawasaividedona3X3plotgridinto9plotsof about37X15m. Samples were drawn at 3 to 5 day intervals over the season from each corner plot and the central plot. This was a total of 5 samples on each sampling date. A field sheet (see appendix) noting the field conditions was completed at each sampling. The number of plants per 6 row-meter was used to estimate stand. The green weight, the number of flowers, number of pods and stage of development, using Lobaron's (1974) standard stages, per 5 plants were recorded as samples of plant growth and development. The insects were sampled using a modified clamp trap described by Leigh et al (1970). The trap had a1 m. deep plastic bag stapled on a 60 X 60 cm. sliding wire framethatcould beclosedtoSOXSOcm. Theopentrapwas placed ovorarowof plants, closed, the plantscut and pushed into the bag. Any insects seen on the ground undertheplantswere aspirated and placedintothe bagandthe bagwassealedinthe field. The bag was then placed in a freezer set at about -20 °C, to kill the insects which were later identified and counted . RESIJLTS WEA'Il-Et Daily accumulated 0050 and precipitation in inches for 1984 and 1985 for the East Lansing Weather Station located about one mile east of the research plots were obtained from the Pest Management Execution (PMEX) computer program system. The accumulation of 0050 had been started 1st. April each year and the sine wave adjustment of Arnold (1970) was used when needed in their computation using the methods of Baskervills and Emin (1969). The accumulated 0050 for the Saginaw Weather Station, centrally located in the area of the study reported by Ruppel and Jennings (1979) were computed using the tabular values for the sine wave adjustment of Gageend Haynes (undated) when needed. The weather data as accumulated 0050 and rainfall for the periods of the study are summarized in Figs. 1 and 2. Soil moisture measurements, that would have aided thisstudy,werenotmadeattheEast LansingWeatherStation andthenotes on soil moisture in the field sheets were the only rough measure of soil moisture availablo.The accumumated DD recorded at the beginning 01th9 1985 season was two times as high as attho start of the season in 1984 (Figure 1). The difference narrowed by later June and the final DD were very close (2405 in 1984 and 2447 in 1985)-attheond ofthe study. In comparison,the DDatSaginaw, about50milesfurthernortl'itl'ianthestudy aea, reported in use Ruppel and Jennings (1979) study for the same period, were slightly less than at East Lansing. The total DD at Saginaw in 1974 at the end of that study period was 2286. The 30 years' average rainfall in East Lansing was 14.43 inches during June through September (Strommen, 1969). Precipitation was low during both seasons of 10 the study (Figure 2 and Table 5). The rainfall during that period was 6.37 inches in 1984 with dry conditions during most of June, the last half of July, and the greater part of August. The soils were dry during these periods. The rainfall during the study in 1985 and was 11.75 inches with dry periods during late June and early July. Much of the rainfall occurred in late August and September in 1985 and the soil was very dry during the earlier growth period of the crop. Preliminary graphs of the number of each species' developmental stages on 0050 were made. These species chosen for further analysis of their phenology were selected on the basis of the frequency and continuity of their numbers. The regression analyses used were modified from the cumulative insect-degree-day (Cum lDD) method outlined by Ruppel (1983). The changes made were primarily the use of programs written in BASIC for the Sharp EL-5500ll computer and the use of simple common logarithms in place of the Texas Instruments model Tl-580 calculator and the tabular logistics values used by Ruppel (1983). mm The beans germinated well in 1984, reached a peak number of about 180 plants per 6 rout-meters at 700 0050, and then gradually declined to about 150 plants at harvest (Flgure 3). Germination of the beans was slow, uneven and poor in 1985. There were about 140 plants per 6 row-meters in the latter part of the season and this dropped to about 130 at harvest. Growth of the plants was vigorous in 1984 except for the droughthy periods from about 1200 - 1500 0050 when growth was extremely slow (Figure 4). Plant green weight peaked at about 550 gm. per 5 plants at 1750 0050 and then declined with maturity. Growth of the plants was late and uneven in 1985. Green weight of 5 plants reached about 275 gm. before declining at maturity. 11 Development of the plants as measured by the growth stages of Lebaron (1974) was regular during 1984 (Table 1). Their development early in the season, however, was uneven. The growth was distorted making the definition of growth stages difficult until a rain at about 650 0050 enabled the plants to grow and develop. Wide x discrepancies were found between the years. in the relationship between growth stage and Julian day, days after planting and 0050. Lebaron divided plant development into vegetative (V) and reproductive (R). Vegetative stages are determined by counting the number of nodes on the main stem including the primary leaf nodes. Reproductive stages are described using pod characters in addition to nodes. The description scheme is summorized as follows: Vl - completely unfolded leaves at the primary leaf node. V2 - first node above primary leaf node. V3 - three nodes on main stem including the primary leaf node. V(n) - n nodes on the main stem, but with blossom clusters still not visibly opened. R1 - one blossom opened at any node. R2 - pods 1/2 inch long at first blossom position. no - pods 1 inch long at first blossom position. R4-pods3incheslong-seedsnotdescemible. R5 - pods 5-6 inches long. R6 - seeds at least 1/4 inch over long axis. R7 ~ oldest pods have developed seeds R8 - leaves yellowing over half of plant. R9 - mature, 80% of the pods showing yellow and mostly ripe. The time and number of flowers per 5 plants were similar in both years in spite of the differences in germination, stand, and growth (Figure 5). Floration began at 1200 - 1300 0050, peaked at about 38flowers per5 plants between 1350 and 12 1450 0050, and was nearly completed by 1700 0050. The number of pods per 5 plants increased very rapidly to about 110 at 1480 0050 and also declined abruptly between 1730 and 1800 0050 to about 55 at harvest (figure 6). Pod numbers increased and decreased more evenly during 1985. They reached a peaknumberof90 at 1720 0050 and declined to 60 at harvest. The yield of the beans in 1984 averaged 1731 g. ( 221.8) per 12 row-meters (equiv. to about 1.688 cwt per acre). The yield averaged 12099. (1112.9) per 12 row-meters (equiv. to about 1.79 cwt per acre) in 1985. The 1985 yield dropped to about 70% of the 1984 yield in this study. The State-wide average yield of dry beans, however, was higher in 1985 (13.2 cwt per acre) then in 1984 (11.0 cwt; data courtesy of Michigan Agricultural Reporting Service). mm NoneoftheknowneanysoasonorsoilinsectpestsofdrybeansinMichigan (see Ruppel et al, 1979) appeared in the study area in either year. The common later season insects were found on the plants of the study. These were: potato leafl'lopper, Empoasca fabae (Harris); Mexican bean beetle, Epifachna varivestis Mulsant; green cloverworm, Plamopena scabra (Fabricius); tarnished plant bug, Lygus Iineolarl‘s (Palisot do Beauvois); bean aphid, Aphis hbae (Scopoli); and bean thrips Goliathrips fasciatus (Pergande). Some spiden'nites, Tetranychus spp. were found in 1984 and some corn rootworm adults, Diabrotica spp. , appeared in 1985. A number of non-pest insects were also found, including predacious lady beetles and ground beetles but only occassionally and in low numbers. Insect numbers were low both years and especially in 1985. Only potato leafhopper adults in 1985 and their nymphs in both years appeared consistantly enough to yield reliable infonnation on their phenology. The date, 0050, and average numbers of the other insect posts are given in Table 2. Regressions of the Cum IDD 13 of adult potato leafhoppers in 1984, '85 and the pooled data for both years were madeonboth DDsoandthesquarerootofDDw Thebostfit, asmeasuredbythe sum of the regression analyses and the expected and 5% limits of estimates of 10%, 50% and 90% points of the populations of the potato leafhoppers are given in Table 3. Graphs of these regressions and their expected bell-shaped curve of insects on 0050 derived from the regressions are given in Figures 7, 8, 9 and 10. DISCUSSION The pattern of growth and development of the dry beans and their insect complex was strongly determined by temperature. This was expected. Drought strongly affected crop development during both years and affected the results of the study. The plateau in growth of the beans, best seen during 1984 (Figure 4), during drought, points up the dependence of plants on water as well as temperature. Phytophagous ' insects generally obtain their water from their host plant and are therefore not so directly affected by drought as are their hosts. Lebaron (1974) notes that bean growth as measured in internode length is controlled by environmental factors. The marked size differences between the bean plants in the two years corroborates this observation. In spite of the 46% increase in rainfall, the high early temperatures in 1985 (610 0050 at planting versus 335 DD50 in 1984) had dried the soils, reduced and delayed genninations, and greatly reduced the vigor of the plants. Floration was initiated at about the same time (1200 - 1300 0050) during both years (I' able 1). ThediflaonceshDDsobetweeanoyearslessenedasmoseasonprogressed. Development of dry beans is a complex process that is affected by photoperiod as well as temperature (Thompson 1939, Padda and Munger 1969). The effect of photoperiod and drought on insects is minimal. Wlth the exceptionoftheMexican boanbeefle,thathasonlybeansandafew other legumes as hosts, the insects studied are polyphagous. They are also multivoltino and have one or more generations before the late planted dry bems becomeavailable. The study showedthatsmallnumbers ofthesespecieswerein dry beans prior to floration. Their number increased consistently after floration. The population changes with the potato leafhopper, the only species that appeared consistently enough to model, followed the expected bell-shaped curve of number of insects on 0050. 1 4 15 The view that insect infestation starts with floration (viz. Ruppel 1981) is not supported by this study. The observed relationship is more probably the coincidence of 0050 than a direct plant-insect interaction. The floration of the beans and the observed subsequent increase in insect numbers are more probably a response to a temperature-time function occuring in the same temperature range for both plant and insect instead of a direct response of the insects to the physiological changes in the plant. The results of the present study are in good general agreement with the older study of Ruppel and Jennings (1979; see Tables 3 and 4) even though different parameters were used. e8. as noted some as .2 seesaw can no? can «mm, .0 LooEchw 2 92:. E0: 0533 5mm 5 do on .0 once m 5.; mxwolooaooo om.m_aE:oo< F 859... «new oa< 33. 0:3. n 0N m «N m vw a $4 a a q I q q a l 4 7 .‘0W 1 . \\ . . 1 00m \. o . . toooa mm R\J w .\\. s \. . n w . . m . B . . toompe . D. O O C. 0 «so? a looow mmm. e vmmp 17 dc: mwmw new vmmw c. 89:03ch scam Eo: 0:5ch .25 um :35? ocESano< N 330E “new oa< 2:3 mean 5 mm m VN m VN m A q A q d u q a 4 I .J o'. 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CON 1 l com 1 1 00¢ I mmmw O 1 000 «mm— o P p r A r L '36M UBGW (6)31UBIO 9 led name can vmmw c. mEmE caps in 0 Lou mamoEac Lose: Co Emmi m .0; 20 Soc .92: co? co: co? 009 l1 4 4 4 A 1 or c a \ -\ \ om \- \ \ on £9 a coma . p r _ E _ _ lo -ou ueew lad Sl8MO|j siueld g 21 mmmw ncm vwm— 5 253a camp >5 m Loo moon *0 52:5: cum} 0 .2“. once .sz comp 00: com. _ 4 l1: mwmwo vmm— 0 ON 0* 00 Dow Btueld 9 led epod to leqtunu ueew 22 «was once :0 ended»: Buncfao. 330a Lo. mLonEnc “comp: cmoE «.35.:an .o Coimoaocm A .3“. emoo .msE 82. com. 8: 82 1 q a d J I a r r on O r . ..ov O C O O u T O l 00 . n O r .k ..on closing to '0U 10 Gal '“mO '|°U 23 co mcaE>c ooww ewes.omoo Legacies. caged .6. 32.63: .ommc. cmoE o>:m_:E:o .o coimoaoom w .oi comp o ncoo .mz: ooh— d comp ON O? on on ‘wno “(95 cu 10 CC“ to SIGGSUI 24 mom. can «we. been co made»: Loaaofwm: Egon L2 mamnEac Comma. cmoE 03.3:an Dm_ooo .0 co_mmo._omm m .0: been .92: oo—m com. ooAF come A a q a 4 q d O . v o o O I . ‘ C O . a C o o O . m C O u C o b I O O O o o 0 v a o I O a. .. 000‘ ON CV 00 ow 'IGB 'UJnO stoesul )0 cu JO OOI 25 .moaocaco_cac:3aaoamceoEscIowmc_m>.:::E:o :m?t.o coammaomm Au? OO—N oom— oeoo dz; ooh— mama-omooazowzaum a .oE ON 0v ow 00 195 'UJn3 sloesull0'0u10 OOI 26 Legacies. cased .2 acts. OOON oom— vnmp .3anaw 3 0000 co 3 and oomEmo pcoocgm cmcE o>2m3an Co co_mmoaocm Fr .3“. once m2: 000p oovp CON? a A a q A a ON 0* om ow 'letl °ou JO om 'tuno eioeeul 27 Tablei. Julian days, days after planting and 0050 to initiation of growth stages (Lebaron 1974) of dry beans in 1984 and 1985. 1 984 1 985a Julian Date of Julian Date of Stage Days planting DD50 Days planting DD50 V1 165 1 O 235 173 1 8 207 V2 1 74 1 9 41 O -- -- -- V3 178 23 479 -- -- -- V4 180 25 51 6 -- -- . '- V5 184 29 575 -- -- ~- V7 187 32 638 -- -- -- V8 1 92 37 727 -- -- -- V9 195 40 971 -- -- -- R1 198 43 863 - -- -- R2 - - - 1 97 42 669 R4 206 51 1 036 —- -- -- R5 21 3 58 1 1 45 206 51 842 PB 23 68 1398 214 59 973 R7 227 72 1473 -- - -- F18 237 82 1661 225 70 1 1 89 F9 241 86 1735 231 76 1 287 3(a)? soil and the resultant poor and uneven germination, rowth, and development e y in the 1985 season made ratings of growths unrelia le. muufis powwow“ muHH—Um EHO3UOOH ChOU— Eh03h0>OHU CUNHU 213 _ 0 Awowmum Hamv mawuzu cmomw . muoaaocumoa cumuomu Amowmum Hacv mvwzam cmumw muaumcp coon cmowx020 wan ucman vcnmacumho m900 omen mzmnluoummv woumaseauuum~ uaavm Snead agave ease .m>ue4 «mo 0000 undo mo and .cmu End 00 0 w 0 u m dumb. mama 0300 0:40 exam nan: 000: 00m: 000: m up .qwoa.wdausv mceau ucuuuuuwv um scum wcmun zuv 00 ounce uucmcw qum we mommum ucuuowufiv mo amass: coo: N cane» £39 muuqe 000000 0 000500 50030000 cuou: Euo3uo>oHu coouov Amowmum Hamv 000000 cmumw 00000000000 cumuomu Amowmum 0000 mvazam cmomu moaucon cmcn cmuwxuzn 0:0 unwaa vucmwcumhu 0000 0000 mzmvlomuwov vuumHSE:uuum~ 00:00 £0200 uasvn c050 m>uma 000 0000 0000 wmmuwx sumo; 0:000 0:000 ommh. 0009 0300 0:00 0:00 000: 000: 000: 000: meuuud .m00a wdwuan mesau ucuumuuwv um comm mcmop zuv uo mumun youmCH qum we wannam ucuuouuwv mo gonads cum: 0 00009 30 Table 4. Results of regression of Cum lDD5o of different stages of the potato leafl'ioppers on DD50 and the expected mean and 5% limits of the 10%, 50%, and 90% points of their populations. 1885 1984 1985 pooleda degrees of freedom 44 48 41 91 cool. of determination 0.9508 0.9518 0.9796 0.9321 F 884.9304 947.0237 1972.8238 1248.9535 intercept -0.0049 -0.0042 -0.0054 -0.0046 8.4668 7.3389 9.3572 7.9917 % upper limit -0.0042 -0.0040 -0.0052 -0.0044 5% lower limit -0.0052 -0.0045 -0.0057 -0.0049 10% population 1551 . 1509 1 554 1526 5% upper limit 1 570 1 530 1 571 1 542 5% Iower_limit 1532 1488 1535 1509 50%)iopulatlon 1747 1734 1731 1733 5°. upper limit 1760 1749 1743 1744 5% lower limit 1734 1719 1718 1721 90% pulation 1943 1960 1908 1940 5% upper limit 1962 1981 1930 1956 5% lower limit 1925 1939 1886 1923 aData of nymphs for 1984 and 1985 pooled for analysis. 31 Table 5. Results of r ression of cumulative mean standard damage rating for potato leafhopper on 0050; 1 74a degree of fredoms 3 coef. of detrermination 0.09842 F 187.1253 intercept -0.0046 slope 7.6961 5% upper limit 00035 5% lower limit -0.0056 10%giopulation 1473 % upper limit 1492 5% lower limit 1452 50% pulation 1681 $2 up r limit 1701 PG . 5% lower limit 1 661 90%:opulation 1890 % upper limit 1908 5% lower limit 1872 aData from Ruppel and Jennings, 1979 32 Table 6. Thirty-yeara mean total and total rainfall in 1984 and 1985 for East Larismg. Month Ween 1.9.85 19.8.5 ‘ June 3.80 0.18 2.91 July 2.88 2.06 2.14 August 3.27 1 .72 3.95 September 2.48 2.97 3.66 31940 through 1969 (Strommen, 1969) The objective of this study was to determine the relationship of population changes of several insect species in relation to temperature and developmental stages of the host plant, dry beans. This study points out that plant development is dependent on at least two parameters, water and photoperiod, that are of minimal importance to insects. Drought strontly affected the growth of the beans during the study. Development of the beans was also influenced by photoperiod and developmental stages of the plants were close in both 1984 and 1985 inspite of their differerences in growth. Photoperiod is of minimal importance to the population changes in the insects. The pattern of growth, however, was regular on D050. The growth of the beans very probably could been predicted as the logistic on 0050 in a “normal" year for rainfall. Temperature alone accounted for nearly all of the changes in the populations of the potato leafhopper. The best fit of their developmental curves was the logistic of their cum lDD on D050. The observed as theoretical points for the potato leafhopper nymphs, especially in 1985, were rather poor (see Figs. 7 and 8). The reason forthe doscrepancy is not known. High temperatures with reduced cover from the stunted plants may have been the cause. The use of common weather data, rainfall and maximum-minimum daily temperatures in this study shows that these data can be used for rough predictions of insect populations. The use of a simple, single parameter, temperature to predict a complex population changes is undoubtedly inadequate. Delong (1965) suggested that a thorough study of the effect of weather on host development may be needed to effectively study host resistance to the potato leafhopper. A more complex model that includes water, photoperiod, and monitoring of the microclimate at the site of 33 34 insect activity is needed for reliable predictions of plant/insect relationships. APPENDIX 35 Appendix: Example of Field data sheet used to describe field condition during sampling. Sampling Methods l-clear Z-hazy bright 3-few clouds h-partly cloudy 5-cloudy 6-overcast l-droughty 2-dry 3-surface dry 4-moist 5-wet 6-muddy l-dry Z-bases moist 3-dewy 4-moist S-wet l-none 2-fog 30mist 4-1ight rain S-intermittant rain 6-heavy rain l-none 2-slight 3-moderate’ 4-gusty S-strong NOTES Crop (stand, virog) Test No. Field Date Observers Time Plant Stage Air temp. Cloud cover Soil moisture Plant moisture Precipitation Wind speed Wind direction Field (weeds, drainage, soil, slope, adjacent fields) Cultural operations Recent weather LITERATURE CITED Anderson, A L 1975. “Navy boaansaroduction: methods for improving yields” Michigan State Univ. Extn. Bull. E- . 7pp. Andrewartha, H. G. and L C. Birch. 1954. WWW Animals, Chicago: The University 0 icago ress. pp 129-206 Apple, J. W. 1952. “Corn borer development and control on canni com in relation to temperature accumulstion" J. Econ. Entomol. 5(5): 877-879. . 1962. “Late-season corn borer and corn oarworm moth flight in relation to larval Eonpulations in sweet corn“ Proceedings: North Central Br., - omol. Soc. Am. 17: 127-130. . Arnold, C. Y. 1959. “The determination and significance of the base temperature a in linear heat unit system” Am. Soc. Hort. Soc. 74: 431-445. . 1960. "Maximum-minimum temperature as a basis for computing heat units” Am. Soc. Hort. Soc. 76:682-692. Baskerville, G. L and P. Emin. 1969. “Rapid estimation of heat accumulation from maximum and minimum temperatures" Ecol. 50: 514-517. Chiang, H. 0.1978 "Insects and their development" in Pfadt, R. E. . New Yorlc Mac-rnillian Publishers Co., Inc. pp. 151-188. Craner, G. R. et al. 1974. ”Seasonal abundance of insect pests of soybeans” J. Econ. Entomol. 67 (4): 487-493. Davidson, J. 1944. 'On the relationship between temperature and rate of of insects at a constant temperature“ J. Anim. Ecol. 13: 26-29. Edwards, C. and G. W. Heath. 1W Entomolmit- Springfield: C as - - Delong, D. M. 1965. "Ecological as of North American leaflioppers and their role in Agriculture“ J. con. Entomol. 13: 408-415. Ga ,S.H.andD.LHa . n.d. .'Degree-da tablesforseveraldevelopmental 99 thresholds” DeptyEngf‘orrIol. Michigan Statye University. Glenn, P_. A 1931. ”Use of temperature accumulation as an index of the time of appearance of certain insect 2pests during the season” Illinois State Acad. Science, Trans. 4: 167-180. Haynes, D. L at al. 1973. 'Enviromental monitorin network for pest management systems" Env. Entomol. 2(5): 9899. 36 37 Headlee, T. J. 1936. ”brood study of the codling moth for one decade” J. Econ. Entomol. 29 (4): 639-646. Lebaron, M. J. 1974. 'A description: sta es of the common bean plant“ University of Idaho Coop. Extn. co, Cur. lnfo. Series No. 228. Leigh, T. F. et al. 1970. "A sampling device for estimatin insect populations on cotton” J. Econ. Entomol. 63(5): 1 04-1706. Luckmann, W. H. 1964. “Heat units for timing corn earworrn insecticide t’rx'enategeritégPl'ogeedings: North Central Br, - Entomol. Soc. Mangat. B. S. and J. W. Apple. 1964. "Heat units and l' ht trap collection as methods for timln corn earworm insectici e treatements' Proceedings: North entral Br., - Entomol. Soc. Am. 19:108-109 Matteson, J. W. and G. C. Decker. 1965. "Devel of the European corn borer at controlled constant and variab e temperatures” J. Econ. Entomol. 58(2): 344-349. Medler, J. T. 1955. ”Method ghpredictig the hatching date of the meadow spittlebug" J. Econ. omol. : 204-205. Michi an State University' Cooperatlv' e Extension Service SU-CES . 1984. 9 “What is biosched?' in Post Alert. 22(6) 18-21. (M ) Padda, D. S. and H M. Munger. 1969. 'Photomnod' , temperature and interactions affecting time of flowerln in beans, Phaseolus vulgaris L." Am. Soc. Hort. Sci. 94: 1 7-160. Peairs, L M. 1914. "Relation of temperature to insect development" J. Econ. Entomol. 7: 175-181. . 1927. ”Some phases of the relation of temperature to the tigelllezvglotlmaeznt of insects' West Virginia Agric. Exp. Station u . : . Ouintance, A L and C. T. Brues. 1905. ”The cotton bullworm" BulL 50, Bureau of Entomol., US. Dept. Agric. Ruppel, R. F. 19833. "Cumulative insect-da as an index of cro protection” J. Econ. Entomol. 76( ): 375-372 . 1983b. “Using a pr rammable calculator for calculating fiat-renal ofani 'DeptofEntomol.ReportNo.7 Mi 'gan Sotgtye Univ; East Lansing, Michigan 8pp. . 1975. “Feeding activity of overwintered adult cereal leaf Eotles and alfalfa weevils at different constant temperatures” Proceeding: North Central Br.,- Entomol. Soc. Am. 30:72-74. . 1986. 'Summa on insecticide and insect lations' unpubfished). ry popu 38 Ruppel, R. F. and Kenneth Dimoff. 1978. ”Tabular values for the logistic curve” Bull. Entomol. Soc. Am. 24(2): 149-152. Ruppel, R. F. and M. S. Gomulinski. 1969. Timing insectide spra for cereal leaf beetle control" Proc.: North Central r., - Entomol. oc. Am. 24(2) 108-110. Ru , R. F. and S. J. Jenni s.1979."Seasonal appearance and relative ppel abundanceofDrybera'hinsects' Dept Entomol. Rpt. No. 1, Michigan State University, East Lansing 5 pp. Sanderson, E. D. 1910. ”The relation of temgerature to the growth of insects" J. Econ. Entomol. 3: 113-13 . . 1908. "The relationshi of temperaure to the hibernation of insects' J. Econ. Entomol. : 56-65. Sanderson, E. D. and L. M. Pearls. 1913. 'I'he relationship of temperature to igusleci “1192's New Hampshire College of Agric. Exp. Station Tech. . , pp. SimpsoR, C. B. 1903. 'I'he coding moth" Bull. 41, Div. Entomol., U. S. Dept. gric. Smucker, J. M. and D. L Mokrna. 1978. 'Enviromental requirements and stress“ in Robertson, L S. and R. D. Frazier Won W. East Lansing. Extn. ull. - 251 :45-60. Strommen, N. D. 1969. ”Climates of Michi n agricultural stations" East Lansing, Michigan: Michigan oather service. Thompson, H. C. 1939. "Temperature in relation to vegetative reproductive ggvselo 679 in plants” Am. Soc. Hort. Sci., Proceedings. Uvarov, e. P. 1931. “Insects and climate“ Trans. of the Royal Entomol. Soc. of London. 79(part 1): 1-19. Way, M. J. et al. 1977. ”Use of forecasting in chemical control of black bean hid, 'sfabae 800 fans i - rown field in beans, Vica fgpbae Leplgllant Path. 26:??I7. pr rig g Wigglesworth. v. B. 1950. WWW London: Methuen and Co. pp. 431-458. . 1972. ' london: Chapman . pp. -699. M'IIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIES 3 1293 0306] 4832 as..- “-2)"