vw fi —-'—'" —— --\ —-‘ “- 1—..- wv' -‘ ____A LABORATORY AND FIELD STUDIES OF {stcncmzs FOR CONTROL or 'i'i-{E CEREAL LEAF mm “mix {or flu Dogma a? M. 5. RICE; EGAH STR'E‘E WHERE??? Young M01: Yun 1954: TH E!!! LIBRARY Michigan State University ABSTRACT LABORATORY AND FIELD STUDIES OF INSECTICIDES FOR CONTROL OF THE CEREAL LEAF BEETLE by Young Mok Yun Under laboratory conditions, carbamates were generally the most effective, phOSphates were moderately effective, and chlorinated hydro- carbons were the least effective class of insecticides against the cereal leaf beetle, Oulema melanopa (Linnaeus). The larvae of the cereal leaf beetle were more susceptible to the carbamates and phos- phates than were the adults. The chlorinated hydrocarbons were equally effective against both adults and larvae. Lindane was highly.effective against the pest at_55O F.; the other insecticides tested killed more slowly at 55° F. than at 800 F, Carbaryl (Sevin) showed a strong ovicidal effect in the labora- tory. Both malathion and Baygon (Bayer 39007; Q-isopropoxyphenyl methylcarbamate) gave limited ovicidal action while dieldrin had little effect on the eggs of the cereal leaf beetle. Carbaryl at a dosage of 1.0 lb. actual per acre caused 100 per- cent mortality of the spotted lady beetle, Coleomegilla maculata lengi Timberlake, within 48 hours following treatment. Guthion (Q,Q:dimethyl 5:4-oxo-l,2,3-benzotriazin-3-(qn)-ylmethyl phosphorodithioate) and malachion also resulted in high mortalities, Baygon somewhat less, while dieldrin, endrin, and lindane had little effect on the spotted Young Mok Yun lady beetle. The difference in selective killing of the cereal leaf beetle and Spotted lady beetle by carbaryl and dieldrin was statis- tically significant. Both malathion and carbaryl were highly effective as grain pro- tectants against the diapausing adults in wheat. Carbaryl at dosages of either 18.75 or 20.00 ppm. gave a complete kill of the beetle within one to three days after treatment. Neither "Pyrenone" (emulsifiable concentrate; mixture of 60% technical piperonyl butoxide and 6% pyrethrins) nor dichlorvos (DDVP) gave satisfactory control of the pest in grain. Under field conditions, carbaryl, dieldrin, endrin, Guthion, Lindane, and malathion gave high initial mortalities of the cereal leaf beetle in wheat and oats. These insecticides also provided the best residual protection. Malathion had much shorter residual effec- tiveness than the other materials. Aldrin, DDT, naled, and parathion also caused high initial kills of the pest, but not as high as the first group. Methoxychlor and toxaphene caused good kills of the young larvae, but neither Phosdrin (2-methoxycarbonyl-l-methylvinyl dimethyl phOSphate) nor diazinon gave appreciable control of the pest. Chlorinated hydrocarbons generally resulted in longer residual pro- tection of the treated plots than did phosphates. The minimum effective dosages of carbaryl and malathion appeared to be 1.0 lb. actual per acre, and 0.5 lb. of Guthion per acre. Dieldrin and lindane each at a dosage of 0.38 lb. actual per acre, and endrin at 0.19 lb. gave satisfactory initial mortalities and residual protection. Carbaryl at 1.0 lb. actual per acre gave higher initial mortality Young Mok Yun as well as longer residual protection of crops than did Zectran (4-dimethylamino-3,5-xylyl methylcarbamate) at 0.5 lb. against the active, newly emerged adults. Only evidence of phytotoxicity observed in the field tests was a distinct damage of DDT in wheat. Endrin, Guthion, lindane, and malathion gave good control of aphids and adult anthomyiids. Dieldrin was moderately effective and carbaryl was poor against the same insects. Carbaryl applied at 1.0 lb. actual per acre caused a slight increase in number of aphids over the check plots. Carbaryl gave fair control of cicadellids while the other five materials showed little effect on the insect. LABORATORY AND FIELD STUDIES OF INSECTICIDES FOR CONTROL OF THE CEREAL LEAF BEETLE BY Young Mok Yun A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology 1964 ACKNOWLEDGEMENTS I wish to express my sincere appreciation to Dr. Gordon E. Guyer, Chairman of the Department of Entomology, for his constant advice and encouragement which made this work possible. Special thanks are extended to Dr. Robert F. Ruppel, under whose inspiration, constant supervision, and unfailing interest this investigation was undertaken. I am greatly indebted to Drs. James W. Butcher, and Roger A. Hoopingarner for reading the manuscript and for valuable criticism and suggestions. Grateful appreciation is also extended to Messrs. Arthur L. Wells, Thomas R. Castro, and Robert B. Carlson for valuable sugges- tions, Messrs. Melvin S. Gomulinski, Dave L.Cobb, and Rhodes E. Thompson for their aid in accomplishing this work, and to the chemical companies for furnishing the insecticides for this work. Finally my thanks are due to Mrs. Arthur L. Wells for typing this thesis. ii TABLE OF CONTENTS INTRODUCTION . Distribution and Economic Importance . Life History . REVIEW OF LITERATURE . LABORATORY EXPERIMENTS . Procedure Experiment I . Experiment II Experiment III . Experiment IV Experiment V . Results Experiment I . Experiment II Experiment III . Experiment IV Experiment V . FIELD EXPERIMENTS Procedure Experiment VI and VII Experiment VIII Experiment IX iii Page 11 ll 12 l6 l7 l8 19 20 20 24 26 27 30 32 32 35 37 39 Results Experiment VI Experiment VII . Experiment VIII Experiment IX DISCUSSION OF RESULTS Laboratory Experiments . Experiments I and II . Experiment III . Experiment IV Experiment V . Field Experiments Experiments VI and VII . Experiments VIII and IX SUMMARY LITERATURE CITED . APPENDIX 1 iv Page 39 39 44 47 50 55 55 55 57 58 59 60 60 62 66 7O 74 Table 10. ll. 12. 13. LIST OF TABLES Effectiveness of insecticides in laboratory tests conducted at 80° F. against the cereal leaf beetle . Number of insecticides in each rated group corresponding to the given categories .Effectiveness of insecticides in laboratory tests conducted at 55° F. against the cereal leaf beetle . Effect of insecticides on hatching of the eggs of the cereal leaf beetle . Effect of insecticides on the spotted lady beetle, Coleomegilla maculata lengi Timberlake, a predator of the cereal leaf beetle Effect of sprays and granules of carbaryl and dieldrin on adults of the cereal leaf beetle and the spotted lady beetle Effect of insecticides on "summer" adults of the cereal leaf beetle in stored grains Occurrence of the different life stages of the cereal leaf beetle on various hosts in Berrien County, Michigan, 1963 . Effectiveness of insecticides against the cereal leaf beetle in winter wheat, 1963 Effect of insecticides on populations of representative insect families in winter wheat Relative abundance of cereal leaf beetle and other insect families in untreated wheat . Effectiveness of insecticides against the cereal leaf beetle in spring oats, 1963 . Effect of insecticides on populations of representative insect families in spring oats Page 21 25 26 28 29 30 31 36 41 42 43 45 46 Table Page 14. Relative abundance of cereal leaf beetle and other insect families in untreated oats . . . . . . . . . . . . 48 15. Effectiveness of different dosages of selected insecticides against the cereal leaf beetle in spring oats, 1963 . . . . . . . . . . . . . . . . . . . . 49 16. Effect of different dosages of selected insecticides on populations of representative insect families in spring oats . . . . . . . . . . . . . . . . . . . . . . . 50 17. Relative abundance of cereal leaf beetle and other insect families in untreated oats . . . . . . . . . . . . 52 18. Comparison of carbaryl and Zectran against late season stages of the cereal leaf beetle in spring oats . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 vi LIST OF FIGURES Figure Page 1. Areas infested with the cereal leaf beetle in Michigan, Indiana, and Ohio in 1963. Two obliquely shaded portions indicate the most heavily infested areas in 1963 . . . . . . . . . . . . . . 5 2. Experimental Sprayer used for laboratory tests . . . . . . l3 3. Sprayed oat plants and the cereal leaf beetle in a growth chamber for laboratory screening tests . . . . . 15 4. Experimental field of oats showing sprayed and unSprayed plots. Lighter areas in foreground and between the plots were untreated and heavily infested with larvae of the cereal leaf beetle . . . . . . 38 vii INTRODUCTION Oulema melanopa (Linnaeus), known as the cereal leaf beetle, has been a serious pest of cereal crops in certain parts of Europe for many years. Both adults and larvae of the cereal leaf beetle feed on young seedlings and the succulent leaves of older plants of cereals and grasses. Oats, barley, and wheat are the three most important crops that are damaged by the pest. The heaviest damage is done to the spring planted grains. In the United States, the beetle was first reported in 1962 from Berrien County, Michigan. Further surveys in the same year revealed that northern Indiana, an area adjacent to the Berrien County, was also infested with the beetle. In 1963 the infested area has been greatly expanded and the beetle was also found in northwestern Ohio. A large acreage of spring grains is also found in this part of the United States. The rapid increase in the population and spread of the beetle was attributed to the fact that the present infested area shares a similar climate with eastern Europe where the beetle causes the most serious damage to the small grains. Unless some immediate control measures are taken, establishment of the cereal leaf beetle in such a favorable area may bring an economic threat to small grain growers in all of eastern temperate North America. In Michigan, the beetle has been damaging grain crops 1 2 since 1959. The beetle population has greatly increased since then and some of the oat fields around Galien, Michigan were severely damaged by the pest in the springs of 1962 and 1963. The area infested with the beetle is now under quarantine by the states of Michigan, Indiana, and Ohio with the support of the United States Department of Agriculture. Both Michigan and Indiana launched a joint research program in late 1962 for control of the beetle. Use of insecticides was necessary in order to reduce the insect population and prevent further Spread of the beetle into other grain growing areas in the United States. During one year period from March, 1963 to February, 1964, sixty-nine insecticides were tested against the pest in the Entomology Laboratory at Michigan State University and fifteen insecticides were tested in the field near Galien, Michigan. The main objective of this paper is to present results of laboratory and field insecticide tests, and to discuss and evaluate the effectiveness of the insecticides used for control of the cereal leaf beetle. Distribution and Economic Importance The cereal leaf beetle occurs throughout most of Europe from England and Wales in Britain to Siberia in U.S.S.R. It was also re- ported from Morocco in North Africa. It is most abundant, however, in the Balkans, the Ukraine, and Caucasus regions. The cereal leaf beetle has long been known as a pest of cereal crops in Europe. Kadocsa (1916) reports that the beetle had been causing damage to the cereal crops since 1831 in Hungary. Periodic (Nthreaks occurred since then and there was a severe loss of crops in 3 1891 in that country. In U.S.S.R., losses of crops due to this pest have been estimated to range from 25 to 50 per cent (Hodson, 1929). In Rumania losses from infestation have been up to 80 per cent of the crop, but in the spring of 1931 the damage was so severe that the entire crop had to be plowed under in certain localities of that country (Knechtel and Manolache, 1936). The beetle was first recorded in Britain in 1917 on oats and barley; and was listed as an important, but not as a major, pest (Hodson, 1929). In the United States, the cereal leaf beetle was first found in 1962 in three townships of Berrien County in southwestern Michigan. Surveys were made in this area by the Michigan Department of Agriculture in cooperation with the Plant Pest Control Division, Agricultural Re- search Service, USDA, and the Entomology Department of Michigan State University. The pest was known to be in Berrien County since 1958 but it was not until July 17, 1962, that a positive identification of the pest was made by Mr. George B. Vogt, Entomology Research Division, Agricultural Research Service, USDA. How the pest reached Berrien County is still unknown. In 1961, the beetle was spotted at U.S. ports of entry on three occasions, twice in New Jersey and once in Detroit (Cooperative Economic Insect Report, 12(32):88l). During the past few years the beetle has been causing various degrees of damage to the small grains in the Berrien area. In 1962, some untreated oat fields in this area were heavily damaged by the pest and the entire crop had to be plowed under. In the same year the beetle was also found in Cass County, Michigan, and La Porte and St. Joseph Counties, Indiana. The spread of the pest continued through 1963 and the beetle was also reported from northwestern Ohio in the 4 6 spring of 1963. In 1963, the total area infested with the cereal leaf beetle in these three states is reported as 312,049 acres (USDA, 1964). The infested area in Michigan, Indiana, and Ohio is shown in Figure 1. Life History The cereal leaf beetle overwinters as an adult inside crevices of fence posts and firewood, under the bark of trees, in leaf sheaths of corn stalks, and in almost any similar tight place protected from direct rain, snow, and wind. The first adult beetles ("spring" adults) come out from their winter hibernation sites during the first warm days of spring and begin to feed, mate, and lay eggs. The adults first feed on the leaves of grasses and winter grains and later move into spring grains where the heaviest feeding and egg deposition occur. The eggs are laid on the upper surface of the leaves of the host plant and hatch in five to ten or more days, depending on the weather condition. The newly emerged larvae feed on the leaves of the host plant and skeletonize them. The larvae acquire a black slimy covering on their body and go through four larval instars. After casting off the black body covering the fully developed larvae enter the prepupal stage and burrow into the soil where they pupate in a small cell. The larval stage ranges from 9 to 12 days, and the pupal stage lasts about two weeks. The newly emerged adults ("summer" adults) feed briefly on the fresh leaves of corn and grasses for about two weeks and then go into aestivation for the remainder of the season. There is only one generation a year under the field condition of Michigan (Ruppel and Castro, 1963; unpublished report). MICHIGAN -----—- ---—-—1.r.;-.--—-w-—"m.'.‘ ' - - - - 0.4. "‘5'" NW [nun-.... nun. u-o ‘ | . - :....o.—---I ' 3;." '0“ . . .... E ---u W ...- .- _‘ "‘ " "In,” .... b‘.‘ o. ... ‘ ‘ '9... .5... a g , . ... 'N . ' ...- - “a... n.-. . '-»- .... _ . . ~ ~; .... _ ' ' ' u 3 . . 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I - " "‘,... . __ l ... . .... ‘. -—- - ‘ -— .— ...... \ J— 1:. _ -- -—- _ "’ ' m" ' Ila-u: ~.- 4 1' 5-,- 7... ... .. o .— -.. ‘ H "'__~ ~ ...—‘91 . ... _._—-.. ...... _. .. 3'. . -"' -... ... ... -- __..—.—~ , -... f", 9—- ‘ _ I 0‘ ’ —- "'-' I _ w - n ... _ - ‘ :3 ,.V . .... - .. I w... _ .a— ‘1 _. *— .... - i ,_._-—-—*- .. __ -. _ ...| ' ,- _ .... -. - - -. .— -—-— l. _ 9:: ....er — . [Lt-.31! INDIANA LEGEND: — autumn: woman BEGJLATED AREA Fig. l.--Areas infested with the cereal leaf beetle in Michigan, Indiana, and Ohio in 1963. Two obliquely shaded portions indicate the most heavily infested areas in 1963. REVIEW OF LITERATURE Use of chemicals for the control of the cereal leaf beetle has long been practiced in EurOpe. However, research work in this field is rather Sporadic and information given is often incomplete and incon- sistant. The articles are written in many languages and only a small number of them are available in the United States. Sudeikin (1913) and Shlchegolev (1915) in the U.S.S.R. reported that inert dusts of ashes and lime are effective against the pest, but the dusts of cement or sand were noted as poor in Rumania by Vereshtchagin (1914). Hodson (1929) attributed a repelling rather than toxic effect to such inert dusts. A few plant derivatives in various forms were among the earliest materials that have been tested against the pest in Europe. Sprays of nicotine sulphate or tobacco extract are reported as effective for the control of the insect in the U.S.S.R. (Vassiliev, 1913) and in Hungary (Jablonowsky, 1914; Kadocsa, 1916;Venturi, 1942). Knechtel and Manolache (1936) state that nicotine is effective but rather expen- sive in Rumania. Urquijo (1940), on the other hand, obtained poor re— sults with nicotine in Spain. A spray of pyrethrum is cited as an effective insecticide against the pest by Hodson (1929), but is also reported as ineffective and expensive by Kadocsa (1916) in Hungary. A mixture of pyrethrum and nicotine, however, is noted as effective against the pest in France (Mesnil, 1931; Balachowsky and Mesnil, 1935). A number of inorganic materials have also been tested in Europe. 6 7 Sprays of barium chloride, either alone or with molasses, are reported to be effective against the pest in the U.S.S.R. by Vassiliev (1913) and Sudeikin (1913), less effective than nicotine in Hungary (Radocsa, 1916) and ineffective in France (Mesnil, 1931; Balachowsky and Mesnil, 1935) and in one report from the U.S.S.R. (Megalov, 1925). Among the inorganic compounds, arsenicals were apparently most widely used in Europe. Sprays and dusts of Paris green, with or without lime, gave good controls of the pest in the U.S.S.R. (Vassiliev, 1913; Sudeikin, 1913; Shlchegolev, 1915), in Rumania (Krassilstchic, 1915; Vereshtchagin, 1914, 1921), and in Hungary (Venturi, 1942). A spray of London purple in combination with lime was found to be effective against the pest in Rumania (Vereshtchagin, 1921). Copper arsenate is noted as poor in Hungary (Kadocsa, 1916) and in France (Mesnil, 1931; Balachowsky and Mesnil, 1935). Sprays of sodium arsenate with lime are reported as effective by Megalov (1925) in the U.S.S.R. Dusts of calcium arsenate with lime are cited as effective against the cereal leaf beetle in the U.S.S.R. (Megalov, 1927; Sagonov, 1936; Starostin, 1944) and in Rumania (Knechtel and Manolache, 1936). Lead arsenate, with or without lime or a sticker, is reported as effective in France (Balachowsky and Mesnil, 1935), in Spain (Urquijo, 1940) and in Yugoslavia (Stankovic and Bjegovic, 1951).. i The number of references on the use of newer organic compounds against the cereal leaf beetle is quite limited. Stankovic and Bjegovic (1951), in Yugoslavia, reports that BHC had a longer residual effect than DDT in the field and the larvae were more difficult to control than adults with these materials. An aerial application of BHC mixed with 2,4-D is reported as effective against the pest in the U.S.S.R. 8 (Voevodin, 1953). Borg (1959) obtained the best results with lindane and parathion. Malathion was as effective as lindane and parathion while DDT, methyl demeton, and "Fosfon acid-ester" (S,S,S,-tributyl phosphorotrithioate) were poor against the pest in Sweden. According to some unpublished survey reports of the Michigan Department of Agriculture, a few farmers around Galien, Michigan, have treated their crops as early as 1959. The materials first used by these growers were DDT and toxaphene (personal communications of Dr. R. F. Ruppel of Michigan State University with the farmers). The results obtained from these materials were rather variable but generally considered as ineffective against the pest. Malathion applied by some farmers in the same area was more effective than DDT and toxaphene and its use against the pest became popular by 1961. Malathion was registered for use against the cereal leaf beetle in 1962. Regulatory officials of the Michigan Department of Agriculture have successfully used methyl bromide for disinfestation of grains, hays, and Straw moving out of the quarantine area in 1962 and 1963. During the 1963 season a total of 36,671 acres (32,661 acres in Michigan and 4,010 acres in Indiana) were treated by aircraft. Ruppel and Wilson (in press), obtained a high control of the spring adults and larvae with both carbaryl and malathion each at the rate of one pound of toxicant per acre in one gallon of spray mixture in aerial applications in 1963. Carbaryl is reported as more effective than malathion because of its longer residual action, and its apparent ovicidal effect. It is equally effective when applied from an altitude of 50 feet or 5 feet. Carbaryl was also found to be most effective when applied with a sticker. The ovicidal action of carbaryl has been previously demonstrated 9 against eggs of Mexican bean beetle, Epilachna varivestis Mulsant, and the oriental fruit moth, Grapholitha molesta (Busck) (personal communica- tions of Drs. R. C. Back and H. H. Moorefield of Union Carbide Chemicals Company). Brunson and Dean (1963) also reported the effectiveness of carbaryl against the eggs of the codling moth, Carpocapsa pomonella (Linnaeus). The ovicidal effect of carbaryl against the eggs of the cereal leaf beetle was first demonstrated by Yun and Ruppel (1964) at the Entomology laboratories of Michigan State University. The spotted lady beetle, Coleomegilla maculata lengi Timberlake, appeared in large numbers in early spring of 1963 and has been observed feeding on the eggs and larvae of the cereal leaf beetle in the fields near Galien, Michigan. Both the cereal leaf beetle and the spotted lady beetle come out from their hibernation at about the same time during the first warm days of spring. Many of the spotted lady beetles fed on the young stages of the cereal leaf beetle until aphid populations (the favored prey of the lady beetle) had considerably increased. At present the spotted lady beetle is considered to be one of the most important native predators of the eggs and larvae of the cereal leaf beetle. The spotted lady beetle commonly feeds on aphids but it is also reported as feeding on the eggs of its own species, and the Colorado potato beetle, Leptinotarsa decimlineata (Say); on the eggs and larvae of several lepidopterous pests of corn and cotton and those of the Mexican bean beetle, Epilachna varivestis Mulsant; on the larvae of the asparagus beetle, Crioceris asparagi (Linnaeus), and the cotton leaf beetle, Chrysomela scripta Fabricius; and on the larvae and pupae of other coccinellid species (Bravo, 1957; Conrad, 1959). Campbell (1952) found that endrin was moderately toxic and 10 dieldrin was slightly toxic to the spotted lady beetle in a laboratory test. Dieldrin, however, had little effect on the spotted lady beetle in the field. Harries and Vacarce (1955) reported that the phosphorus compounds were generally more toxic to two species of predatory coccinellids, the convergent lady beetle, Hippodamia convergence Guer, and the spotted lady beetle Coleomegilla maculata (Deg.). Bartlett (1963) indicated that the toxicity of dieldrin was medium to high to Some parasitic Hymenoptera and none to medium to some predatory Coccinellidae. Malathion and carbaryl, on the other hand, were highly toxic to both groups of insects. Living summer adults of the cereal leaf beetle were found in grains in storage in Michigan. The insect hiding inside folded leaves and leaf-sheaths of small grains at the time of harvest was the cause of infestation of harvested grains. The beetle is known to survive in stored grains for several months (unpublished report, Michigan Depart- ment of Agriculture). Malathion is registered for use in stored grains. It's effectiveness against the cereal leaf beetle in grains has been demonstrated by author under the direction of Dr. R. F. Ruppel at Michigan State University. Malathion is now widely used for disinfes- tation of grains in Michigan. The author could not obtain any informa- tion from European literature regarding the use of grain protectants for the control of the cereal leaf beetle in grains. LABORATORY EXPERIMENTS A study was initiated in late 1962 to investigate effectiveness of insecticides for use in the protection of the cereal crops in the infested area and the prevention of further spread of the beetle into other grain producing areas. Insecticides known to be effective in Europe and on related species in the United States were tried along with a large number of newer materials which appeared to be promising (USDA, 1962). All experiments were conducted in the Entomology Labo- ratories at Michigan State University during the period of March, 1963 through February, 1964. The laboratory tests were conveniently divided into the following five experiments depending on the nature of the test. Experiment I: Tests of insecticides against the cereal leaf beetle larvae and adults at 80° F. Experiment II: Tests of insecticides against the cereal leaf beetle larvae and adults at 55° F. Experiment III: Tests of insecticides against the cereal leaf beetle eggs at 80° F. Experiment IV: Tests of the relative toxicity of insecticides to a coccinellid predator of the cereal leaf beetle at 55° F. and 80° F. Experiment V: Tests of grain protectants against the summer adults of the cereal leaf beetle in grains. Procedure Young seedlings of oat variety "Clintland 60" were used for all experiments except Experiment V. The seeds were planted in clay pots ll 12 of four-inch diameter and allowed to grow to a height of about four inches before they were used for testings. All of the insecticides used were standardized commercial formulations obtained directly from the manufacturers. The identification of those insecticides without approved common names is given in the Appendix 1 (Frear, 1962; Kenaga, 1963; USDA, 1964). The sprays were applied to the plants using a experimental sprayer designed by Dr. R. F. Ruppel of Michigan State University. The sprayer was equipped with a Sprayer Systems Company "TC-0.7" solid cone nozzle operated at a line pressure of 35 psi and was calibrated to deliver a rate equivalent to 65 gallons of spray per acre. The nozzle suspended about nine inches above the plants gave a complete coverage of the plants with a minimum run-off of the spray material (Figure 2). Experiment I Sixtyenine insecticides from various sources have been tested against the pest. The dosage of the insecticides used was either the usual dosage of the insecticide in the field or, in the case of the experimental material, that suggested by the manufacturer. After plants were treated with a spray they were allowed to dry before the insects were placed on them. Calcium arsenate dust was applied by placing plants inside a box and using a small hand duster to apply a measured amount of the dust over the plants. The box was closed until all the dust suspended inside the box had settled. All of the cereal leaf beetle larvae and adults used for the tests were obtained from a culture maintained at Michigan State Univer- sity. In the tests against the larvae, only the second and third in- stars were used because the fourth instar larvae, when placed on treated Fig. 2.--Experimental sprayer used for laboratory tests. 14 plants, had a tendency to go into pupation prematurely. Upon close ex- amination, most of these prematurely pupating larvae were found dead inside the pupal case in the soil. The larvae from the culture were carefully transferred to the treated plants using a pair of light-weight forceps. A minimum injury to the larvae during this transfer process was obtained by gently scraping the larvae off the plant with the for- ceps and placing them on the treated plants. The treated plants with the larvae on them were then covered tightly with a nylon-capped lamp chimney. For the adult beetles, the lamp chimney was first set tightly on each pot, the beetles were placed on the treated plants through the opening at the top of the chimney, and the opening was quickly covered with a piece of nylon cloth. This procedure was used to prevent any possible escape of the active beetle during the transfer process. All sixty-nine insecticides were tested against the larvae of the cereal leaf beetle and only a limited number of materials were tried against the adult beetles. General screening of insecticides was mainly aimed at larval stages because the larvae were known to be generally more difficult to kill than the adult beetles (Stankovic and Bjegovic, 1951), and it was also possible to obtain large numbers of larvae as compared with the relatively small stock of adult beetles that was available. The insects on the treated plants were held in a growth chamber set at 80° F., 65 percent relative humidity, and a 16- hour light period (Figure 3). The environmental temperature of 80° F. was selected for the general screening because it was expected that in- sect activity was higher and death was faster and less variable at 800 F. than at lower temperatures. Untreated plants were used as checks and a randomized block 15 .mumou wawaomuom huoumuonma you nonsmco :u3ouw o cw ofiuoon wmoa Hmonmo ozu pom munmfid uwo commummun.m .wwm \ ‘ \. , . i ) ' “1‘.-. 16 design with three replications was employed for this experiment. Each pot with ten insects served as a plot, giving a total of thirty insects per treatment. Counts of living and dead insects were made 24 and 48 hours after the insects had been placed on the treated plants. The data were converted to percent mortality (Abbott, 1925) and the insecti- cides were rated as excellent, good, fair, or poor based on the 95 percent confidence interval for a sample size of 30 (Snedecor, 1948).' The rated groups so determined are not exclusive, but are sufficiently precise for the objective of the experiment. The data obtained from the ratings were then analyzed for independence of factors using a Chi-square test. Experiment II The purpose of this experiment was to determine the effective- ness of some of the selected insecticides against the pest at a low temperature under laboratory conditions and to compare the results with that obtained at 80° F. Only seven insecticides that showed promise in the field trials in 1963, and three experimental materials were included in this experiment. The dosages used for the first seven insecticides were those determined in the field tests. Method of applying the in- secticides and design of the experiment were exactly the same as in the first experiment. In this experiment the insects on the treated plants were held in a special cabinet adjusted at 55° F., 80 percent relative humidity, and 12-hour light period. Counts of living and dead insects were made more frequently in this experiment than in the Experiment I since the kill of insects appeared to be slower at this low temperature than at 800 F. The original data were then converted to percent mortality. l7 Experiment III Three separate tests were made at the Entomology Laboratories to compare the ovicidal effect of carbaryl, malathion, Baygon, and dieldrin. All of these four insecticides were effective against the cereal leaf beetle in the field trials and the dosages used for these materials were those determined in the same field trials in 1963. In addition to carbaryl and malathion, mixtures of carbaryl-tetradifon and malathion-tetradifon were also tested in the first test. Tetradifon, an acarine ovicide, was included in the test because it was hoped that it might increase the ovicidal effect of carbaryl and malathion. Eggs of the cereal leaf beetle were obtained by exposing fresh oat plants for one day to actively ovipositing females of the pest in a cage. The plants were then removed from the oviposition cage and the number of eggs deposited on the plants were counted. In the first test, only thirty eggs were allowed to remain on the plants in each pot. Since this method was laborious, all the eggs on the plants were simply counted in the second and third tests. There were approximately 120 eggs in the second and 90 eggs per treatment in the third test. The Isecond test was essentially a confirmatory one and only carbaryl was retested. In the third test, Baygon and dieldrin, along with carbaryl, were tried against the eggs of the cereal leaf beetle. The insecticides were applied to the plants using the same ex- perimental sprayer described in Experiment I. The treated plants with eggs were held in a growth chamber that was set at 80° F., 65 percent relative humidity, and 16 hour light period. The environmental condi— tions noted are those that were being used for the rearing of the cereal leaf beetle. The external signs of development and hatching of 18 the eggs and survival of the newly hatched larvae were checked and re- corded once a day. Untreated plants and eggs were used as checks and a randomized block design with two replications was employed for all three tests. Experiment IV The objective of this experiment was to find selective insecti- cides that are highly effective against the cereal leaf beetle while causing the least possible damage to the spotted lady beetle, a predator of the cereal leaf beetle eggs and larvae. Two separate tests have been conducted under laboratory conditions to determine the relative toxicity of seven insecticides to the spotted lady beetle. All seven insecticides were tried against the adults of the spotted lady beetle in the first test. In the second test, only carbaryl and dieldrin, each in spray and granular forms, were tried against both the cereal leaf beetle and the spotted lady beetle to see if the methods of application of insecti- cides would affect the kill of the two species of insects. The method used in both tests was essentially the same as in Experiment I. The seven insecticides selected for the first test were those effectively used for the control of the cereal leaf beetle in previous field trials in the spring of 1963. They were carbaryl, Guthion, malathion, Baygon, dieldrin, endrin, and lindane. The dosage used for each insecticide was the minimum that would give effective control of the cereal leaf beetle. Active adults of the spotted lady beetle were collected in corn fields in East Lansing. Thirty lady beetles were used for each treatment. The treated plants, after the lady beetles had been placed on them, were held in a growth chamber set at 80° F., 65 percent relative humidity, and 16 hour photoperiod. 19 The granular formulations used in the second test were applied by sprinkling measured amounts of the granules over the plants. The dosages used for the granular applications were slightly higher than those used in sprays. A higher dosage for granular insecticide would be needed because the insects would have less contact with the granules than with the spray deposits. The adults of the cereal leaf beetle were obtained from a laboratory culture and that of the spotted lady beetle were collected in an overwintering aggregation near Standish, Michigan, in October of 1963. Adults of both the cereal leaf beetle and the spotted lady beetle were placed together on the treated plants. Thirty each of the two species of insects were used for each treatment. The insects on the treated plants were held in a special cabinet ad- justed to 55° F., 80 percent relative humidity, and 12 hour light period. The low temperature was used to approximate the conditions when the insecticides would be applied in the field. Untreated plants , were used as checks and three replications arranged in a randomized block were used in both tests. Counts of the numbers of living and dead beetles were made at regular intervals after the insects had been placed on the treated plants. Experiment V The objective of this experiment was to find insecticides which would give adequate control of the cereal leaf beetle in stored grains. Three separate tests were made in the Entomology Laboratories to com- pare the effectiveness of four candidate grain protectants against the 'summer adults of the cereal leaf beetle. In the first and third tests, (Dne kilogram of clean wheat of the variety "Monon" was weighed for each treatment. The wheat sample contained 9 percent moisture. The weighed 20 sample was placed in a white enamel pan and a spray was applied over the grain using the experimental sprayer. Application of granular in- secticide was made by sprinkling measured amounts of granules over the wheat sample in a clean ice cream carton. In both cases, the grains were thoroughly mixed immediately after each treatment to give a uniform coverage of an insecticide on the grain sample. The dosages used for the insecticides were those currently recommended for general grain protection. The treated grains were divided into three BOO—gram samples and each of these samples was placed in a one-pint jar. For the second test, wheat samples were obtained from a granary located in Buchanan, Michigan. The samples treated with malathion by regulatory officials were sent to the Entomology Laboratory of Michigan State University for testing against the cereal leaf beetle. Three 300-gram samples of both treated and untreated grains were made for the second test. Thirty adults of the cereal leaf beetle were placed in each jar, capped with a nylon cloth, and all the jars were held in a growth chamber that was set at 80° F., 65 percent relative humidity, and 16 hour light period. Untreated grains were used as checks and a ran- domized block design with three replications was used in all three tests. Counts were made of the number of living beetles in each jar 24, 48, 72, and 120 hours after the beetles had been placed in each jar. Results Experiment I Sixty-nine insecticides tested in the laboratory against the larvae of the cereal leaf beetle are listed and grouped in descending 21 order of effectiveness in Table 1. Twenty-one insecticides in Group I are rated as "excellent"; eighteen materials in Group II as "good"; fourteen insecticides in Group III as "fair"; and sixteen materials in Group IV as "poor". Classes of the insecticides used are identified in the second column of the table as carbamate, phosphate, chlorinated hydrocarbon, miscellaneous, and confidential. Sixteen insecticides were tested against both the larvae and adults. TABLE l.--Effectiveness of insecticides in laboratory tests conducted at 80° F. against the cereal leaf beetle Percent mortality; hours after treatment Class Larva Adult of Dosage; Insecticide insecticide Form. lb/acrea 24 48 24 48 Group IC AmCy 47031 phos 3.0 ECb 1.00 100 -- B-10046 phos 4.0 EC 1.00 100 -- Dylox phos 50 WP 1.00 100 -- 80 100 Isolan carb 2.0 EC 0.50 100 -- ML 749d phos 8.0 EC 1 .00 100 -- Ortho 5655 carb 2.0 EC 0.75 100 -- Phorate phos 4.0 EC 1.00 100 -- 83 97 Rotenone misc 0.4 EC 0.25 89 92 3 13 Rotenone misc 0.4 EC 1.00 100 -- SD 8530 carb 50 WP 1.00 100 -- Upjohn 12927 carb 75 WP 0.25 55 Upjohn 12927 carb 75 WP 1.00 100 —- Baygon carb 1.5 EC 0.50 98 100 Zectran carb 2.0 EC 0.50 97 B-10119 phos 4.0 EC 1.00 96 100 Bayer 44646 carb 1.5 EC 0.50 96 100 Bayer 25141 phos 4.0 EC 0.50 96 NIA 10242 carb 50 WP 0.50 96 100 Ortho 5353 carb 2.0 EC 0.75 96 100 Carbaryl carb 85 WP 0.50 71 98 Carbaryl carb 85 WP 0.75 83 100 Carbaryl carb 85 WP 1.00 93 100 83 97 Malathion phos 8.0 EC 0.50 55 78 Malathion phos 8.0 EC 0.75 68 85 Malathion phos 8.0 EC 1.00 93 100 63-80 67-93 Dichlorvos phos 8.0 EC 1.00 93 100 70 87 TABLE 1.--Continued 22 Percent mortality; hours after treatment Class Larva of Dosage; Insecticide insecticide Form. leacre 24 48 24 48 GS 13005 phos 25 WP 1.00 92 100 Group IIC GC 4072 phos 4.0 EC 0.50 84 100 Dimetilan carb 50 WP 1.50 84 97 Guthion phos 2.0 EC 0.50 83 100 67 83 AmCy 47470 phos 3.0 EC 0.50 81 100 Imidan phos 3.0 EC 1.00 80 96 Endosulfan chlor 2.0 EC 0.50 79 100 27 77 AmCy 47548 carb 2.0 EC 0.75 72 96 Meta-Systox-R phos 2.0 EC 0.75 69 93 Bayer 37344 carb 50 WP 0.50 62 Lindane chlor 1.65 EC 0.38 100 -- Lindane chlor 1.65 EC 0.50 61 100 100 -- Bayer 41831 phos 4.0 EC 1.00 59 97 Bidrin phos 8.0 EC 1.00 59 96 Pyrenone misc 60-6 EC 1.00 72 86 GO 3707 phos 4.0 EC 0.50 21 GO 3707 phos 4.0 EC 1.00 71 86 TEPP phos 3.0 EC 0.75 71 78 Methyl Trithion phos 4.0 EC 1.00 64 82 AmCy 38906 carb 3.0 EC 0.50 62 88 Delnav phos 4.0 EC 1.00 61 89 Group IIIC Bayer 37289 phos 4.0 EC 1.00 51 100 Demeton phos 2.0 EC 1.00 43 93 Heptachlor chlor 2.0 EC 0.75 34 93 Cal. arsenate misc 7 dust 3.00 26 96 Endrin chlor 1.6 EC 0.50 21 96 77 Aldrin chlor 2.0 EC 0.50 48 83 67 Chlordane chlor 6.0 EC 1.00 48 89 Ethion phos 4.0 EC 1.00 48 89 ML 7488 phos 8.0 EC 1.00 48 69 SD 7438 phos 1.6 EC 0.75 38 79 SD 7438 phos 1.6 EC 1.00 43 79 Parathion phos 4.0 EC 0.25 28 Naled phos 8.0 EC 0.75 20 Methoxychlor chlor 2.0 EC 1.00 14 0 0 SD 8447 phos 1.0 EC 0.75 13 38 23 TABLE 1.--Continued Percent mortality; hours after treatment Class Larva Adult of Dosage; Insecticide insecticide Form. lh/acre 24 48 24 48 Group IVC Dieldrin chlor 1.5 EC 0.38 57 97 Dieldrin chlor 1.5 EC 0.50 7 100 83 Dimethoate phos 4.0 EC 0.50 10 Dilan misc 5.0 EC 1.00 7 42 AmCy 43913 conf 2.0 EC 0.50 7 15 Kepone chlor 3.0 EC 0.50 7 8 Ciodrin phos 6.0 EC 1.00 4 l9 Di—Syston phos 6.0 EC 0.50 4 Bayer 29493 phos 4.0 EC 0.50 3 12 AmCy 52160 conf 2.0 EC 0.50 l 35 SD 8448 phos 2.0 EC 0.75 0 33 Mirex chlor 3.0 F1. 1.00 0 9 Toxaphene chlor 6.0 EC 0.50 0 7 Toxaphene chlor 6.0 EC 1.50 O 60 DDT chlor 2.0 EC 1.00 0 Diazinon phos 4.0 EC 0.50 0 Lead Arsenate misc 94 WP 3.00 0 0 Phosdrin phos 2.0 EC 0.25 0 a . . . The dosages are given as pounds of active tox1cant per acre. b . . . . The emulsifiable concentrate formulations are given as pounds of active toxicant per gallon. CInsecticides were grouped in descending order of effectiveness based on 95 percent confidence interval for a sample size of 30. EMixture of naled and malathion (1:2 ratio). eMixture of naled and malathion (1:1 ratio). The larval and adult mortalities were compared using the data based on 24-hour counts for the sixteen materials. A statistical analysis indicated that the mean mortality of the larvae and that of the adults were not significantly different when all sixteen materials 24 were included in the analysis. The larval mortality in carbamates and phosphates, however, was significantly higher than that of adults. Chlorinated hydrocarbons were equally effective against the both stages. Table 2 shows the relative number of insecticides falling into the given categories. This information was obtained from Table 1. All of the carbamates tested in the laboratory fall into the first two groups of better materials while ten out of twelve chlorinated hydro— carbons fall into Groups III and IV of poorer materials. Phosphates are more or less equally distributed among the four groups. The associa- tions of carbamates with Groups I and II and chlorinated hydrocarbons with Groups III and IV were statistically significant. In the second categories of old and new materials, more new materials are found in Groups I and II than in III and IV, but this association was not statistically significant. Using two dosage levels, 0.5 lb. per acre or less and 0.75 lb. per acre or more, no significant associations were observed between the dosage levels and rated groups. Experiment II Among the ten materials tested in this experiment, six of them were tried against both the larvae and adults of the cereal leaf beetle. Carbaryl and lindane caused a rapid kill of the insect. A 100 percent mortality of both the larvae and adults was obtained with carbaryl within 48 hdurs after treatment. With lindane, the larval mortality was 100 percent at the end of 48 hours and the adult mortality was 93 percent at 48 hours and 100 percent at 72 hours. Malathion and Guthion showed somewhat slower kill of the pest than carbaryl and lindane, but still caused 97 and 93 percent mortality of the larvae at 48 hours and 100 percent kill of the adults at the end of 96 hours. The kill 25 obtained with dieldrin, endrin, and aldrin was much slower than the four previous materials and the adult mortality ranged only 78, 74, and 78 percent respectively at the end of 5 days. A statistical analysis indicated that the difference between the larval and adult mortalities was not significant when the data for the first six materials were used for the analysis. The results of this experiment are shown in Table 3. TABLE 2.-—Number of insecticides in each rated group corresponding to the given categories Group Category I II Subtotala III IV Subtotalb 2X2 Carbamate lO 4 (l4) 0 O (0) Phosphate 10 ll (21) 8 7 (15) Chlorinated hydrocarbon 0 2 1(2) 5 5 (10) 18.72 Old (registered) 8 11 (19) 10 12 (22) New (experimental) l3 7 (20) 4 4 -(8) 3.30 0.5 1b./acre or less 7 7 (14) 3 9 (12) 0.75 lb./acre or more 14 11 (25) ll 7 (18) 0.01 aSubtotal for Groups I and II. bSubtotal for Groups III and IV. 26 TABLE 3.--Effectiveness of insecticides in laboratory tests conducted at 55° F. against the cereal leaf beetle Percent mortality; hours after treatment Dosage; Insecticide Form. 1b./acrea Stage 4 16 24 48 72 96 120 Carbaryl 85 WP 1.0 Adult 3 55 79 100 Larva 7 37 77 100 Lindane 1.65 ECb 0.38 Adult 0 48 79 93 100 Larva 7 70 97 100 Malathion 8.0 EC 1.0 Adult 7 48 76 86 96 100 Larva 3 37 77 97 Guthion 2.0 EC 0.5 Adult 0 41 69 86 89 100 Larva 3 27 83 93 Dieldrin 1.5 EC 0.38 Adult 0 0 0 7 18 56 78 Larva 0 3 30 77 Endrin 1.6 EC 0.38 Adult 0 0 0 17 39 56 74 Larva 0 3 7 37 Aldrin 2.0 EC 0.5 Adult 0 0 0 17 36 56 78 NIA 10242 50 WP 0.5 Larva 50 83 AmCy 47470 3.0 EC 0.5 Larva 40 53 Am Cy 52160 2.0 EC 0.5 Larva 3 7 m a a O O The dosages are given as pounds of active tox1cant per acre. b . . . . The emu151f1able concentrates are given as pounds of active toxicant per gallon. Effectiveness of certain insecticides tested at both 800 F. and 55° F. was also compared. A statistical analysis did not reveal any significant difference between mean mortalities of the insects at these two temperature levels. Experiment III Most of the eggs (88 percent) treated with carbaryl continued 27 development until head capsule of the embryo was formed. All but a few of the egg cases ruptured at this final hatching stage and their contents dried. Only 0 to 7 percent of the eggs treated with carbaryl actually hatched and these larvae all died shortly after hatching. The effect of malathion and Baygon on hatching of the eggs was rather moderate and 32 to 42 percent of eggs treated with malathion and 34 percent of eggs with Baygon hatched. All of the larvae treated with Baygon died shortly after hatching. There was 65 percent hatching of eggs in dieldrin treated plots where untreated plots in the same test yielded 63 percent hatch. The newly hatched larvae on the dieldrin treated plants lived for l or 2 days before they died. In untreated plots, 65 to 80 percent of the eggs hatched. All but 3 to 7 percent of the larvae that hatched from untreated, malathion, and malathion- tetradifon plots lived and completed apparently normal development. The addition of tetradifon to carbaryl and malathion did not alter the effectiveness of these insecticides. The results of this experiment are summarized in Table 4. Experiment IV Carbaryl caused 100 percent kill of the spotted lady beetle within 48 hours following treatment. Guthion and malathion also caused a high mortality of 100 and 97 percent respectively at the end of 72 hours. Baygon was more moderate to the coccinellids than previous three materials and gave 41 percent mortality of the insect at the end of 72 hours. Dieldrin caused only 3 percent mortality of the Spotted lady beetle and neither endrin nor lindane showed any effect at the end of 72 hours. The results of this test are shown in Table 5. 28 TABLE 4.--Effect of insecticides on hatching of the eggs of the cereal leaf beetle Percent hatch; days after treatment Dosage; Insecticide Form. lb./acrea 4 5 6 7 10 Carbaryl 85 WP 1.0 3 3 3 Carbaryl/tetradifon 85 WP/0.8 ECb 1.0/0.25 5 7 7 Malathion 8.0 EC 1.0 22 30C1 32 Malathion/tetradifon 8.0/0.8 EC 1.0/0.25 15 40C1 42 No insecticide --- --- 40 80 80 Second Test Carbaryl 85 WP 1.0 0 1 1 1 No insecticide --- 19 66 71 73d Third Test Carbaryl 85 WP 1.0 0 O 0 0 Baygon 1.5 EC 0.5 6 31 32 34C Dieldrin 1.5 EC 0.5 20 53 59 65° No insecticide --- --- 17 49 59 63d V. a . . y The dosages are given as pounds of active tox1cant per acre. b . . . The emulsifiable concentrate formulations are given as pounds of active toxicant per gallon. cAll the larvae died. dA few of the larvae died. 29 TABLE 5.--Effect of insecticides on the spotted lady beetle, Coleomggilla maculata lengi Timberlake, a predator of the cereal leaf beetle Percent kill; hours after treatment Insecticide Form. 1b./acrea l 8 24 48 72 Carbaryl 85 WP 1.0 20 50 83 100 -- Guthion 2.0 Ecb 0.38 o 23 40 97 100 Malathion 8.0 EC 1.0 0 0 20 87 97 Baygon 1.5 EC 0.5 O 0 7 30 41 Dieldrin 1.5 EC 0.25 0 0 O 3 3 Endrin 1.6 EC 0.12 0 0 0 0 O Lindane 1.65 EC 0.25 O O O 0 0 aThe dosages are given as pounds of active toxicant per acre. bThe emulsifiable concentrate formulations are given as pounds of active insecticide per gallon. Table 6 illustrates the relative effectiveness of carbaryl and dieldrin to the cereal leaf beetle and the spotted lady beetle. The kill of both species of insects was much slower in all treatments than in previous tests. Carbaryl caused 90 to 93 percent mortality of the cereal leaf beetle and 81 to 84 percent mortality of the spotted lady beetle at the end of 5 days. During the same period, dieldrin killed 69 to 86 percent of the cereal leaf beetle and only 31 to 50 percent of the Spotted lady beetle. The difference in the selective killing of the two species of insect by the two insecticides were statistically highly significant. The mortality obtained from the granular formula- tions in both insecticides appeared to be somewhat slower than that from the spray formulations, but these differences were not statis- tically significant. There were no significant differences in mortality of the two species of insect obtained by the different formulations of the insecticides. 30 TABLE 6.--Effects of Sprays and granules of carbaryl and dieldrin on adults of the cereal leaf beetle and the spotted lady beetle _r Percent mortality Carbaryl Dieldrin Hours after a b d Insect treatment Granules Spray Granulesc Spray Cereal leaf beetle 24 13 3O 7 0 48 33 53 13 23 72 53 57 20 53 96 83 67 47 80 120 90 93 69 86 Spotted lady beetle 24 10 53 7 17 48 30 63 10 27 72 37 63 17 30 96 50 64 ll 32 120 81 84 31 50 a107. granules applied at a dosage equivalent to 1.5 lb. of active toxicant per acre. b857. wettable powder applied at a dosage equivalent to 1.0 lb. of active toxicant per acre. CSZ granules applied at a dosage equivalent to 0.5 lb. of active toxicant per acre. dAn emulsifiable concentrate containing 1.5 lb. actual per gallon applied at a dosage equivalent to 0.38 lb. of active toxicant per acre. Experiment V Malathion at either 10.0 or 10.4 ppm treated in the laboratory at Michigan State University gave a 100 percent kill of the cereal leaf beetle at the end of 3 days, while the same material at 5.0 ppm killed only 86 percent at the end of 5 days. Malathion treated at a dosage of 10.0 ppm in a granary in southwestern Michigan caused 100 percent mortality of the beetle at the end of 24 hours. Carbaryl at either 18.75 or 25.00 ppm resulted in 100 percent kill at 24 hours and dichlorvos at 1.25 and 2.50 ppm killed only 51 and 11 percent of the beetle respectively at the end of 5 days. The results of this experiment are shown in Table 7. 31 TABLE 7.--Effect of insecticides on "summer" adults of the cereal leaf beetle in stored grains Percent kill; hours after treatment Dosage; Insecticide Form. ppma 24 48 72 120 Malathion 5.0 ECb 10.4 86 99 100 -- Pyrenone 60-6 EcC 14.2/1.42 38 46 68 87 Second Test Malathion 5.0 EC 10.0 100 -- -- -- Third Test Carbaryl 85 WP 18.75 100 -- -- -- Carbaryl 85 WP 25.00 100 —- -- -- Malathion 5.0 EC 10.00 90 94 100 -- Malathion 5.0 EC 5.00 55 77 78 86 Dichlorvos 25 Cd 1.25 0 36 35 51 Dichlorvos 25 G 2.50 0 0 0 11 a . . . . . The dosages are given as parts of active tox1cant per million. bThe emulsifiable concentrate formulations are given as pounds of active toxicant per gallon. c"Pyrenone Grain Protectant" of Fairfield Chem. Div. containing 60% piperonyl butoxide and 6% pyrethrins. d 25% Dichlorvos on resin granules. FIELD EXPERIMENTS One of the most urgent problems arising from the establishment of cereal leaf beetle into the New World was to find a means of pro- tecting individual fields of small grains from damage. Chemical con- trol of the pest was the first step being considered in this problem since there were good chances of quickly finding insecticides which would give adequate controls of the pest. The main objective of the field experiments was to find materials that are effective against the pest under field conditions, and which could be recommended immediately for use against the pest. Procedure European literature on the use of newer organic compounds against the pest was rather scarce, and the laboratory screening of insecticides against this pest at Michigan State University was only at the be- ginning stage when the first field application of insecticides had to be made in 1963. Therefore, a review was made of insecticides used for control of pests that are closely related to the cereal leaf beetle. These related species were principally the three-lined potato beetle, Lama trilineata (Olivier), asparagus beetles, Crioceris spp., and Colorado potato beetle, Leptinotarsa decimlineata (Say). Fourteen in- secticides that were known to be effective against these related species were carefully selected for field trial by Dr. R. F. Ruppel of Michigan State University. All of the materials selected were 32 33 registered for use in either small grains or other field crops. The insecticides used in all experiments were fresh commercial formulations obtained directly from the manufacturers. The insecti- cides were applied in the field using an experimental ground sprayer that was slightly modified from one developed by Dr. W. F. Meggitt of the Department of Crop Science, Michigan State University. A compressed—air sprayer with a line siphon valve was mounted on a tractor. The tractor speed was adjusted to apply 35 gallons of spray per acre at a line pressure of 40 psi through six fan nozzles (Sprayer Systems Company No. 73-0462) bored on a nine-foot boom. The boom was side- mounted to the right and gave complete coverage of a ten-foot swath. Five empty fire extinguishers of 2.5-gallon capacity were mounted on the rear of the tractor and used as spray tanks. These containers were used because of their convenient size, ease of handling and washing, resistance to corrosive materials, and ability to withstand relatively high pressure. No agitation of sprays was necessary with the formula- tions that were used. Four different insecticides were placed in four outside containers, and a middle container was filled with water for flushing the lines and boom after each application. Four different treatments were made with a single load of spray materials in one trip. This method saved considerable time of spray operation in 1963. The plots used in all experiments were 10 feet wide and 30 feet long, and were arranged in a randomized block design with four replica- tions. The plots in each block were laid out in such a way that the insecticides could be applied from the left side of the plots by the boom extended perpendicular to the right hand side of the tractor with- out driving through the plots. The effects of Spray drift were minimized by applying the Sprays during early morning hours when the 34 wind was slight. The plots in each block were contiguous, and were sprayed in their entirety. Only the central portion of each plot was used for sampling and rating to avoid the effects of overlap of the sprays around the edges. Two fields of wheat and oats near Galien, Michigan were selected for the experiments. These fields had been planted and were cared for by private farmers who were cooperating in this study. The wheat used was the variety "Vigo" and had been planted on September 24, 1962. Both adult and larval damage in the field were heavy early in the spring. The wheat plants at this time, however, were large and there was no danger of loss of stands. No insecticides were applied in this field except in the experimental plots. The oats used were the variety "Rodney" and had been planted on April 5, 1963. This was one of the earliest plantings of oats in this area in 1963 and young plants were severely damaged by adult cereal leaf beetles early in the spring. The oat field, except for the portion used in the first test, was sprayed on May 3, 1963, with malathion at a rate of one pound actual in about 15 gallons of spray per acre. This spray was applied to protect the Stand of the oats, but the field was rapidly reinfested by the adult beetles and subsequent larval damage was extremely heavy. Both fields were rather irregular in respect to soil, drainage, and weeds. They were selected for the experiments because of their extremely high infestations of the pest. During the spring of 1963, there were several very warm days in late March during which the overwintering beetles apparently became active. The temperature then dropped down and remained unseasonably cool during most of April and May. It became hot and dry in early June and there was no rain until the first week of July. The prevalence of the different stages of the 35 pest in the wheat and oat fields in 1963 are shown in Table 8. The data were obtained by Mr. T. R. Castro of Michigan State University during his study on the biology of the cereal leaf beetle. The field experiments were arranged as follows: Experiment VI: Tests of insecticides against the cereal leaf beetle in wheat. Experiment VII: Tests of insecticides against the cereal leaf beetle in oats. Experiment VIII: Test of dosages of selected insecticides against the cereal leaf beetle in oats. Experiment IX: Test of carbaryl and Zectran against "summer" adults in oats. Experiments VI and VII Two tests were conducted in each experiment. The first applica- tions using all fourteen insecticides were made in both fields on May 3, and the second applications in different plots of the same fields on May 25. The first applications were made the day after the x first larvae were discovered, and the second applications were made when most eggs had hatched in the wheat. Counts were made on May 13 in the wheat and oat plots where applications were made. A random sample of twenty Stems was collected in the central portion of each plot, and the number of living larvae of the cereal leaf beetle was counted. For the second tests in both experiments, counts of the number of the larvae per twenty stems were made on May 28. Visual ratings of the amount of damage in each plot were made on June 4 using the "standard rating" system of Stewart (1954) with the following classes: 0--no damage seen; l--damage difficult to find; 2--damage scarce; 3--damage common; 4-—damage to plants obvious; 5--damage to plots 36 .SSQSQ osu Eoum powuoao kasoc o>mn umfiu omono mum muasbm :Hoasdmzn .oawu mwnu um woumo>um£ mm3 mHon osao .wcfinam onu CH oompofio mam monoucw3uo>o m>m£ umnu omo:u ohm muaaom :wcfludm:m ma umsws< H masm 1 mm Scam ma meow moaned :uoeaom: pumnouo Hm wash a Scam 1 om an: a mo: om>umq mam OH Scam N %m2 1 ON kum< w HHHQ< mwmm humamo poem Hm kud< n ma kua< mm noun: moanwo :wcfiudm: "mommmuw 66H sane SN mesa ma mesa muaaem :nmESSm: H sane Ha mesa - on as: a max 6m>nma as mass on as: - On an: SN Hausa swam m sane mm mm: - a as: 3N Hana< muaaem :weauam: sumo Seesaw om AHSW SN mesa NH meow nmufidpm :uosasm: ma Scam m wash 1 mm km: N km: om>nmg ma 6:34 me as: - a ma: SH Hausa mwmm om Aasn AN Hausa - ma Hausa H Hauaa manages :mcauamz names nausea venom ummq xmom venom umuam owmum Swag umom 60>Hmmn~0 mmumn mama .amwfinowz .hucsoo cowuumm ow mumon msowum> no ofiuoon mama Hmouoo mo mowmum owwfl ucouommam ago «0 mucouusooOuu.w mqmumH nuHB woumomaq haw>mo£ mam mmuwmuuc: whoa muoaa onu :ooBuon mam mcdouwouow 6% women Hounwgq .muon mmhmudmas can mommudm wawzonm Sumo mo paowm HmuaoEHHSQXM1u.¢ .me ..I..4. . ...uwx.4 «(1.43. xi....M ... c r . a 5... ._ . . flux. .. a “‘9. .c‘r?..... . 01.x} AW. to ex..- .I.J.4. . ..l.‘ ..‘.‘.. . .r..$.o..~ , o .N ..‘0 {WW}. 39 Experiment IX An application of carbaryl and Zectran was made on June 30 to compare the effectiveness of these two materials against the late- season stages of the cereal leaf beetle in oats. The plots were selected in one of experimental fields where the oats were planted late in the Spring. The oats in the test plots were heavily infested with active "summer" adults. The eggs and larvae of the cereal leaf beetle were extremely scarce when the insecticides were applied. Carbaryl was applied at 1.0 lb. and Zectran was applied at two dosages of 0.5 and 0.25 lb. actual per acre using the same experimental ground Sprayer described before. The first counts were made on July 1 for numbers of eggs and larvae per 50 Stems, number of living adults per 20 sweeps using a 15- inch insect net, and also for number of dead adults per square yard in the central portion of each plot. The second counts were made on July 9 for numbers of living and dead adults. Results Experiment VI The number of larvae in the plots treated on May 3, 1963 was extremely low when they were examined on May 7 and May 10 (Table 8). There was an average of 1.15 larvae per stem in the untreated plots when the first counts were made on May 13. Carbaryl gave 94 percent control of the larvae 10 days following treatment. The control obtained from chlorinated hydrocarbons, except methoxychlor, ranged from 81 to 87 percent. An average number of larvae found in the plots treated with naled, Phosdrin, and diazinon slightly exceeded that found in the 4O untreated plots. The results obtained from this test are Shown in Table 9. Table 9 also illustrates the results obtained from the second application that was made on May 25, 1963. A greater number of larvae had hatched at this time and the control appeared to be more satisfac- tory. Counts of larvae were made on May 28 and there was an average of 2.16 larvae and 1.42 eggs per stem. Carbaryl, dieldrin, endrin, Guthion, lindane, and malathion gave 94 to 99 percent mortality of the larvae; aldrin, DDT, naled, and parathion gave 75 to 87 percent mor- tality; the remaining four materials, diazinon, methoxychlor, Phosdrin, and toxaphene, gave 31 to 54 percent mortality.‘ Visual ratings of the plots made on June 4 generally corres- ponded to the ratings of the materials based on the larval counts made on May 28. DDT caused a reddish coloration and necrosis of the tips of the leaves that was prominent to the time of maturation of the plants. Twenty sweeps with an insect net were made on June 6 in the untreated plots and in the plots treated with the six most promising materials. Relative numbers of the cereal leaf beetle and some of the associated insects for each treatment are shown in Table 10. Larvae of the cereal leaf beetle were the most abundant insects collected; an average of 163 larvae per 20 sweeps in the untreated plots. The control of the larvae with the better materials was still high and comparable to that obtained on May 28. The adults of the cereal leaf beetle were extremely Scarce in the wheat by this time and there was less than one adult per 20 sweeps in the untreated plots. Aphids were the second most abundant group with 27.5 per'20 sweeps. Guthion, lindane, and 41 .mo>moH up mafia woos ammo :medudm one mamouooc ago 6 momsmu Hana .muoHd woumouuc: uo>o om>umH mo ommouoefi uswwam w .coHHmm Hod unmowaO o>wuom mo amazon mm co>ww who maofiumfisauom mumuucoocoo oHanmwmadao msHo .vmwmamv maouo>om macaquuom :m: cu doom omemm o: now :0: mo mwcflumu anamw> co vommm n .ouom Mom unmowxou o>wuom mo amazon mm co>ww mum mowmmoo anew om.q -- -- -- -- -- meaoauummsa oz ma.¢ -- mm a m.o om 0.4 coaanmnn oo.s -- am a m~.o um o.~ :Hnumonm om.m -- am am m.H om o.6 measamxon om.N -- as we o.H um o.N Hodsosxonumz om.~ -- mm a nk.o om o.m emamz om.~ -- as so mN.o om o.s consumumm 6m~.~ -- mm mm o.H om o.~ Hon mk.a -- am am m.o om o.~ anneaa mN.H as as as o.H om o.m acasumamz mN.H mm «a ma m.o om o.~ censuso om.a mm as Hm mN.o om 6.3 nausea ma.o as as as o.H m3 mm deemsnmo oo.H as no mm m.o om me.a sewage; oo.H ooH mm 6m m.o com n.H canvases d OCDH. o mfififi wN hm: mH hm: ”dofiuoaflmh N mahom\.n: .Ehom mvHUHuUOmGH m mmz.mmowaaa< mommmon mommamn COwuodmou N a mm as: emaaaaa mama .umoss noucfia cw maumon mama Hmouoo onu umcwmwm movfiowuoomcfi mo mmoco>AOUSMMMuu.m mqm<8 42 .coHHmw nod unmoflxOu m>wuom mo amazon mm cm>wm ohm mcoHumHSEuom oumuuooocoo ofinmwmamfisao 6390 .oumu kHoEouuxv ouo3 mmHuoon uH3m< v .momH .o mama so meme mums mmo63wo .ouom nod unmonOO o>wuom mo amazon mm co>ww mum mowmmom one a .moaa .mN hmz co mowaddm ouo3 momHoHuoomch ma.ma u mo.ama mn.o mm.m om.oH om.mm mm.moH 1- u- mowowuoomcfl oz oo.H om.N mm.m mw.m mm.m oo.H om o.w cownumfimz oo.m mm.¢ mm.H mN.m oo.w om.o om o.N cofisuow om.m m~.o mn.H mN.oH. oo.¢ mm.o om o.H cfiuocm om.~ mN.N oo.m 00.6H mm.a oo.a a: ma Hsnmnnmo mn.~ om.H oo.~ oo.m om.o om.o om mo.H ocmocfiq mm.m oo.H mm.m mN.mN mm.o om.o mom m.H awumfiowm mmficoomum mkuwz mpawhEo:uc< mvwnd< om>um~ nouom\.nH .Buom moowowuoomcH - pmflumon mood Hmmuoo mommmon omaoo3m om nod uoomcw..o: owmuo>< umosz nouaw3 a“ moHHHEmm uoomcw o>wumuaomondoa mo mcowumHsaod co movwofiuoomaw mo uoowmmuudfl mgmwuom mo amazon mm cm>ww mum macaumHSEuow oumuucoocoo oHnmNmHmHDEo SSH U .momH .o Scam no meme ohms mdoosmo .ouom Hod unmowxou o>wuom mo amazon mm cm>fiw mum mommmom oan .momH .mN hmz no Umfifiadm whoa movwofluoomch Nm.Ha u mo.ama n~.o mm.oH m~.~H ma.am ms.mq ma.mas -- -- SSEUHSUSScH oz om.n om.m om.N oo.aa om.¢m mm.am oo.H om 0.x consumamz om.m mk.a oo.m mk.oH m~.m3 on.~m om.o om o.~ censuso oo.HH mN.m om.k 00.34 ma.~e oo.¢m mN.o om 6.H caseem mk.m ma.H ma.HH om.mm oo.s~ om.nH oo.H a: mm Henmnumo om.m oo.s om.o mm.oH m~.om oo.q¢ om.o om mo.H Susanna ma.w mN.e m~.~ mk.oH on.¢m oo.a~ om.o com m.H caneaman maafiamemoao manna: m8aa»56:uc< meaza< muase< 68>nmq nwnmm\.na .EEom mmenoauommaH .o mmon oHuoon mama Hmouoo omdmoBm ON pom uoomCN .oa owmuoa< mumo magnum SH moHHHEmm uoomcw o>wumucomoudmu mo moowumHSQOQ no mongoguommnw mo uUSMMMun.mH mgm<9 47 except malathion still maintained good controls of the cereal leaf beetle (Table 11). There was an average of 31.75 aphids and 12.25 anthomyiids per 20 sweeps in the untreated plots. All of the insec- ticides, except carbaryl, reduced the number of these two groups of insects. Only a slight reduction of aphids and no appreciable reduction of anthomyiids were obtained with carbaryl. Carbaryl gave the highest and Guthian the lowest reduction of mirids. No reliable data were ob- tained on the effect of these insecticides on cicadellids and coccinellids. Relative abundance of insect families found in untreated oats is shown in Table 14. Experiment VIII The previous tests in wheat and oats indicated that carbaryl, dieldrin, endrin, Guthion, lindane, and malathion all gave higher initial control of the pest than did the other materials. Application of the better materials was made on June 5 to the oats to see whether lower dosages used would give control of the pest comparable to that obtained in previous tests. Counts of larvae were made on June 7 and June 25, and sweep samples were taken on June 13. As Table 13 indicates, control of the larvae obtained on June 7 and June 13 was very high in all treatments. There was an average of 4.02 larvae per stem on June 7 and 41.67 larvae per sweep on June 13. Eggs and adults were scarce on these dates. The number of damaged plots for each treatment was counted on June 19. All four plots of both untreated and those treated with the lower dosage of malathion, and one each of the plots treated with the lower dosages of carbaryl and Guthion showed fresh damage by the pest when checked on June 19 (Table 15). 48 TABLE l4.--Relative abundance of cereal leaf beetle and other insect families in untreated oatsa Average no. insect Percent of Family per 20 sweeps total Chrysomelidae Q, melanopa: Adults 43.75 7.42 larvae 473.75 80.33 Others 1.00 0.17 Aphidae 31.75 5.34 Anthomyiidae 12.25 2.08 Miridae 10.25 1.74 Cicadellidae 6.25 . 1.06 Coccinellidae 2.25 0.38 Chloropidae 2.25 0.38 Curculionidae 1.25 0.21 Lauxaniidae 1.00 0.17 Piesmidae 1.00 0.17 Chrysopidae 0.50 0.08 Fulgoridae 0.50 0.08 Braconidae 0.25 0.04 Neididae 0.25 0.04 Cantharidae 0.25 0.04 Otitidae 0.25 . 0.04 Phalacridae 0.25 0.04 Nitidulidae 0.25 0.04 Miscellaneous 0.50 0.08 aSamples were taken on June 6, 1963. 49 .muoHd pmumouuc: uo>o ommmuocH uanHm v .coHHmw Hod unmoHNOu m>Huom mo amazon mm co>Hw mum mcoHumHDEuow mumuucmocoo oHanMHmHaam msHo .unwsouw one oHuoon mmoH Hmonoo osu ha ommemb oo3osm umnu muoHd mo .unom mHnHmmOQ m mo .uoneac msH .muom nod unonNOu o>Huom a mo monsoa mm am>Hw mum mmwmmoo onHm q 11 -1 11 u: u- moHoHuommcH oz ¢ m cm Sm mm.o o qN om mm o.H om o.w COHnumHmZ H 0N mm mm mm.o o Nw ooH mm m.o om o.N aonudw 0 mm OCH OCH mH.o o no ooH mm mN.o om o.H :Huvam H on mm mo mm.o o as as ooH o.H a3 mm Henmnnmo o no OCH OCH wm.o o Hm OCH OCH m.o om mo.H mcmocHH o no ooH mm mm.o o mm ooH mm m.o oum m.H cHuvHoHn an mesa “muoHd mN Scam mH wand n coda monom\.nH .EHOh mmHoHuoomCH vomemm .oz Hommmoa coHuosomu N m mash mva Haa< momH .mumo.wcHumm SH QHUOQQ NMOH HMQHQU wr—U umfiwmwm mQUHUfluommGH Umuumfimw MO mmwmmOU UGQHQMMHU NO wmmGQ>MUUGMWWII.M.—H fight 50 Counts of larvae were made again on June 25. A sharp reduction in control of the larvae was observed in the plots treated with both dosages of malathion and lower dosages of carbaryl and Guthion. The other treatments still maintained a high degree of control on this date. There was an average of 0.82 larvae per stem in the untreated plots, eggs were not observed, and active "summer" adults were common in all plots. Relative numbers of the cereal leaf beetle and other important insects for each treatment are shown in Table 16. The data were ob- tained from the sweep samples made on June 13. Endrin, Guthion, lindane, and malathion (all at both dosages), gave good reduction in the numbers of aphids and anthomyiids. The higher dosages of carbaryl gave a fair reduction of the anthomyiids but caused a Slight increase in the number of aphids. Cicadellids were numerous by this time but the data obtained were inconsistent within plots to give reliable con- clusions. All insecticides except carbaryl had little effect on the cicadellids. Relative abundance of various insect families represented in untreated oats is shown in Table 17. Experiment IX Carbaryl gave a higher initial mortality of 84.75 dead beetles per square yard compared to 47.25 and 49.75 beetles for Zectran. There were only 7 dead beetles in the untreated plots. The numbers of eggs and larvae of the cereal leaf beetle were so few in the plots that no reliable data were obtained. Another count made on July 9 also indi- cated the largest number of dead beetles in the plots treated with carbaryl and moderate to lowest number of dead adults in the plots 51 .muom Hod unmonou o>Huom mo mocsoa mm am>Hw mum mommmom ozH .aoHHmw nod uCSUHxOO o>Huom mo mpcsoa mm co>Hw mum mcoHumH55uom oumuucmocoo oHanmeHSEo SSH o .mme .mH mash co moms ouoB mdmoswo a .momH .m wand no voHHdam ouo3 mooHoHuoomaHm m~.m~H 1 mo am; m~.~q oo.~m ma.qa mk.o m~.mmm -- -- seaonuommaa oz mm.os m~.oH mN.- om.m oo.om mk.o ma.me oo.oH mA.AH ma.m mm.km oo.H om o.m coanumHmz m~.os oo.mH mN.¢H ma.m m~.NH wm.o mk.me oo.HH ma.6H mN.H ma.m om.o om o.~ coaguso mk.km m~.m~ m~.s~ mN.H ma.o AH.o ma.on mN.mH oo.- on. om.m mN.o om 6.H esteem mN.mN om.om oo.mm m~.m om.sH ma.o mN.mN mm.eo oo.6m m~.~ m~.6 oo.H a3 mm Henmnnmo om.q6 oo.kH mN.HN mA.H mN.~ mm.o oo.mm mk.qH ma.m~ oo.H o om.o om m6.H seaweed oo.km ma.o~ cm.om o mk.H wm.o oo.qq om.am oo.m8 on.H om.H om.o com m.H :HHSHSHQ mUHHHmUmUwU mfiwfiafi mUwaAEOSquw muHSU< mm>umd Dmuum\ .n: .EHOh mwkuwuummGH oHuomn wmoH Hmouoo mowmmoa omdomam ON nod uommcH .oc owmuo>< mumo wcHudm :H moHHHEmm uoomcH o>Humucomoudou Ho mooHumHSQOQ no mooHoHuoomcH mouooHom Ho mommmow ucououmHu mo uoommm:u.oH mHmHuom mo amazon mm co>Hw mum maoHumHDEuow oumuucoocoo oHamHHHmHSEo mzH w .oumm mumsvm pom muHsvm moon mo Hones: mmmuo>HH.Ho Hones: owmuo>< U .mEoum om nod om>umH no wwwo mo popes: ammuo>Huom mo wUCSOQ mm co>Hw mum mmwmmom one Q .momH .om Scam so voHHmam ouo3 momHoHuoomch om.w oo.Nm oo.n oo.¢m oo.¢ mN.o u- u. mmHoHuoowcH oz oo.mm mN.mN mm.m¢ mN.NH om.o om.o mN.o om o.N cmuuooN mN.moH mN.oN mN.mq mn.NH om.o o m.o mom o.N cmuuooN 2.2m 2.: 2.8 9m 34 o o; as S HEELS owuHsvm pmqumm omuHsom wmuHamm oom>umH omwwm nouow\.nH .Euom mmmHoHuoomCH omen o>HH moon o>HH Howmmon m mHsm m.oc owmuo>< H mHsm m.oc owmuo>< mumo wcHudm CH mHuoon mmoH Hmouoo ego mo mowmum common oumH umchwm cmuuooN mam Hkumnumo mo GOmHumanoun.mH mHm