rfiw ‘H “W M; W MI W Ill "1 I l H ll I'j I H l H ‘4 «ll Amd 104:. l (DOG-b LEAF PUBESCENCE EN COMMON WHEAT, TRETECUM AESHVUH L. AND DEFFERERT 353393 0F SCREENING FOR CEREAL LEAF BEETLE. GULEMA MELANOPUS L, RESESTARCE Thesis for the Degree 9f 3%. S. WCHEGAN 3m ' UWEESETY R‘JSSELL FREE?) 19?!) lHtS" LIBRARY Michigan State a, University w v “w— ar ‘ , amnma av V HUM; & SBNS' marmme ABSTRACT LEAF PUBESCENCE IN COMMON WHEAT, TRITICUM AESTIVUM L., AND DIFFERENT METHODS OF SCREENING FOR CEREAL LEAF BEETLE, OULEMA MELANOPUS L., RESISTANCE BY Russell Freed The pubescence of four spring wheat varieties showed a highly significant difference between leaves. Leaves one, two, and four (the flag leaf), had the most pubescence. The four spring wheats differed significantly in cereal leaf beetle oviposition preference in tests on both the seedlings and the fully elongated plants. Many eggs were laid on the near glabrous variety and only a few were laid on the pubescent varieites. Larval weight gain and survival were also reduced significantly on the pubescent varieties in both the seedlings and the elongated plants. Five of the seven fully elongated winter wheat selections showed a significant difference in the number of eggs the cereal leaf beetle laid on them when compared to the two check varieties. Only one of the winter wheat selections showed a significant reduction in larval weight gain when compared with Genesee, but five were Russell Freed significantly lower when compared with selection 29. Only one selection significantly reduced larval survival. Larval feeding on the winter wheat variety Genesee resulted in a 7% reduction in yield as reflected in a loss of kernel weight when approximately 25% of the flag leaf was destroyed. No reduction in pastry quality was noted. LEAF PUBESCENCE IN COMMON WHEAT, TRITICUM AESTIVUM L., AND DIFFERENT METHODS OF SCREENING FOR CEREAL LEAF BEETLE, OULEMA MELANOPUS L., RESISTANCE BY _‘ RussellnFreed A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of CrOps and Soil Science 1970 ACKNOWLEDGMENTS The author wishes to express his sincere appreci— ation to Dr. E. H. Everson for his help and guidance throughout this study and for his constructive criticism in preparing this manuscript. Thanks are due also to Mr. R. V. Connin for supplying the insects and to Drs. D. H. Smith, S. G. Wellso, and J. A. Webster for their advice and assistance. Appreciation is also expressed to Dr. C. M. Harrison for his critical review of the manuscript. ii TABLE OF CONTENTS INTRODUCTION . . . . . . . LITERATURE REVIEW . . . . . MATERIALS AND METHODS . . . . Pubescence Study . . . . . Oviposition Test . . . . . Larval Weight Gain Test. . Oviposition and Larval Feeding Segregating Winter Wheat Selections Damage to Genesee Wheat. . . RESULTS AND DISCUSSION. . . . Pubescence Study . . . . . Oviposition Test . . . . . Larval Weight Gain Test. . . Tests Oviposition and Larval Feeding Tests Segregating Winter Wheat Selections . Damage of Genesee Wheat. . . LIST OF REFERENCES . . . . . APPENDIX . . . . . . . . iii on Page 12 12 13 13 17 17 17 19 21 24 Table LIST OF TABLES Page Number of Leaf Hairs per 1.02 mm2 Leaf Area for the Varieties CIll490, C19321, Hope, and Chris Averaged Over the Three Planting Dates . . . . . . . . . . . . . 13 Analysis of Variance for Leaf Hair Density of Four Spring Wheat Varieties CIll490, C19321, Hope, and Chris When They Were Planted on Three Different Dates at the Same Location . . . . . . . . . . l4 Oviposition Test and Larval Weight Gain with Four Spring Wheat Varieties in Both the Seedling Stage and Fully Elongated Stage . . . . . . . . . . . . . 16 Oviposition Test and Larval Weight Gain with Two Susceptible Checks and Seven Winter Selections in the Heading Stage with Field Resistance. . . . . . . . 18 Kernel Number, Kernel Weight, Pearling Index, Flour Yield, and Alkaline Water Retention Capacity Tests of Genesee Winter Wheat with Approximately 25% of the Flag Leaf Destroyed and Undamaged Plants . . . 20 Duncan's New Multiple Range Test Comparing the Four Different Leaves of Four Spring Wheat Varieties, CIll490, CI9321, Hope and Chris. . . . . . . . . . . . 24 Duncan's New Multiple Range Test Comparing Four Spring Wheat Variety Means . . . . 24 Analysis of Variance Table for Oviposition Test on 3 Leaf Seedlings of Four Spring Varieties, CIll490, CI9321, Hope and Chris. 25 iv Table 7 Page 9. Analysis of Variance Table for Oviposition Test on Fully DevelOped Spring Wheat Varieties, CIll490, CI9321, HOpe and Chris. 25 10. Analysis of Variance Table for Larval Weight Gain on 3 Leaf Seedlings of Four Spring Varieties, CIll490, CI9321, Hope and Chris. . . . . . . . . . . . 26 11. Analysis of Variance Table for Larval Weight Gain on Fully Developed Plants of Four Spring Varieties, CIll490, C19321, Hope and Chris. . . . . . . . . . . . 26 LIST OF FIGURES Figure Page 1. Photomicrographs of Leaf Samples from CIll490, CI9321, Hope and Chris Showing Pubescence Per 1.02 mm2 (100x) . . . . . . . . . 9 2. Leaf Cages Used to Confine First Instar Larvae on Flag Leaf for Larval Weight Gain Tests. . 11 vi INTRODUCTION Since its introduction into Michigan in 1962, the cereal leaf beetle, Oulema melanopus L., has spread North to southern Ontario, South to central Kentucky, West to eastern Illinois and East to eastern Pennsylvania. Ap— proximately 10% of the small grain acreage in the United States is in the present range of the cereal leaf beetle (25) . Plant breeders and entomologists realized the threat that the beetle posed and control programs were initiated. An unsuccessful eradication program was followed by a containment program. When these programs were under- way, crop scientists searched for resistant small grain varieties which could be used in breeding programs. Ringlund and Everson (17) studied the mechanisms of resistance and showed a high negative correlation be- tween leaf pubescence and larval weight gain. Plants with many leaf hairs were resistant to the cereal leaf beetle. Much of the screening for cereal leaf beetle resistance has been done in field studies. Greenhouse screening has been done on the basis of seedling pubes- cence, oviposition preference, and larval weight gain. Most of the wheat in Michigan is winter wheat which has fully tillered and is in the jointing stage when the beetles appear in the spring. Since much of the screen- ing for resistance is done on seedlings, the relationship of pubescence and insect behavior between the seedling stage and the more developed stages of the plant should be established. The aim of this research was to study the vari— ation in pubescence between the leaves of three spring varieties with known cereal leaf beetle resistance and the leaves of one nearly glabrous susceptible variety. Methods of insect screening were evaluated at the three leaf seed- ling stage and the mature plant. Seven Michigan winter wheat selections with field resistance in 1969 were also screened. Finally, the effect of beetle feeding on grain yield and quality of the winter wheat variety Genesee was assessed. LITERATURE REVIEW Damage to small grains in EurOpe by the cereal leaf beetle, Oulema melanopus (L.), was reported in 1737 (3). It probably was introduced into the United States in southern Michigan in the late 1950's and identified in Berrien County, Michigan, in June of 1962 (3). Castro eE_gl, (3) discuss the life cycle of the cereal leaf beetle. It overwinters as an adult in crevices of soil or plant crowns, under the bark of trees or other objects offering protection. The beetles appear when the the spring temperatures rise above 60 F. Mating occurs and egg-laying begins about 10 days after emerging. The eggs are usually laid close to the midvein on the upper surface (adaxial) and near the basal end of the leaf. Eggs hatch in four days at 86 F and in 23 days at 59 F. The larvae feed and remain on the upper surface of the leaves throughout their four instars. Upon com- pletion of the fourth instar the larvae enter the soil to a depth of approximately two inches, form a pupal case, and pupate. The pupal period varies from twelve to twenty-five days depending on the soil temperature (3). The cereal leaf beetle feeds upon many species of the family Graminaceae. It prefers to feed upon oats, bar- ley, wheat, orchardgrass, quackgrass, timothy, foxtails and fescues (26). The major damage by the cereal leaf beetle is done by larval feeding on the leaves. The larvae strip the leaf of the mesophyll and leave only the veins and lower cuticle intact. Gallun (7) reported that larvae feeding on Monon wheat caused a 12% reduction in kernel number, a 23% reduction in kernel weight, and a significant differ- ence between samples in water retention capacity. The search for resistance to the cereal leaf beetle has been very successful in Triticum. In screening 14,444 varieties from the United States Department of Agri- culture World Wheat Collection Everson g£_al. (5) found 323 lines originating in Asia Minor with field resistance indicating that this area may be a major gene center for cereal leaf beetle resistance. Painter (11) divides the mechanism of insect resistance into three types; namely antibiosis, preference or non-preference, and tolerance. Painter defines anti- biosis as "the tendency to prevent, injure, or destroy (insect) life." Preference or non-preference is used "to denote the group of plant characters and insect responses that lead to or away from the use of a particular plant or variety, for oviposition, for food, or for shelter, or for combinations of the three." Tolerance occurs when "the plant shows an ability to grow and reproduce itself or to repair injury to a marked degree in spite of supporting a population approximately equal to that damaging a sus- ceptible host." Gallun §E_gl. (9) reported that resistance of wheat to the cereal leaf beetle may be due to oviposition preference by the adult and low feeding incidence by the larvae. Schillinger gt_§l. (22) reported a three fold effect of pubescence. The first effect is oviposition non-preference by the adult beetle. The second is desic- cation of the eggs caused by improper leaf contact. The final effect is a toxic action upon the first instar larvae. Pubescence was not the only factor conditioning resistance. He proposed that oviposition non—preference along with physical or chemical factors which retard the growth and development of the larvae, confers resistance. Ringlund and Everson (17) found a high correlation between pubescence density and larval weight gain. Plants with the most pubescence resulted in the lowest larval weight gains. Leaf hair genes or other genes closely linked to them might be responsible for the factors of resistance. They also found that hair density varied between wheat varieties, leaf number, and leaf surface. The first two leaves of the varieties studied, had the highest den- sity of leaf hairs. Leaf hair density has been shown by Parnell et_al. (13) to confer resistance in cotton to leafhoppers (Empoasca). Afzal and Ghani (l) have shown that leaf hair density in cotton can be increased or decreased with different planting dates. Leaf hairs are protuberances of epidermal cell walls of cellulose and lignin, and highly vacuolated with thick secondary walls (4). Screening populations for cereal leaf beetle damage has been conducted in several ways. The initial efforts were done with field studies, recording the damage done by natural infestations. Schillinger (19, 21) de- scribed larval feeding and oviposition preference tests as methods of measuring resistance. Each of the screening methods mentioned showed differences in the varieties which were classified as resistant. Schillinger (19) found that 20% of the selections classified as resistant in field studies were also classified as resistant with larval weight gain tests. The other 80% had less re- sistance to larval growth. Shade and Wilson (23) showed a highly significant correlation between temperature and rate of oviposition. At temperatures ranging from 45-80 F the regression showed that for every 1 F increase in temperature there was a 0.38 increase in eggs laid per female per day. They also showed that as the population density increased the rate of ovi— position per female decreased. MATERIALS AND METHODS Pubescence Study The four spring wheat varieties used in this study were CIll490, CI9321, Hope and Chris. CI11490 and C19321 are highly pubescent Russian varieties from the United States Department of Agriculture World Wheat Col- lection. Hope is moderately pubescent, while Chris has only a few leaf hairs. To check the variation of leaf hair density be- tween leaves under natural growing conditions, these varieties were space planted in the field on three dates one week apart beginning the second week of May. The seeds were planted in separate plots using a completely random design with three replications. Each plot contained 21 plants so that each plant was used for only one sample. From each plot three samples were taken of each leaf and averaged to reduce the variation caused by leaf size. Leaves were numbered in order of development--from oldest to youngest. Leaf samples approximately 1 cm long were taken from the middle of the leaf and placed in a 50-50 solution, by volume, of chloral hydrate and phenol. After 24 hours the samples were removed and placed in 85% lactic acid until the hair counts could be made. The samples were then placed on a glass slide and covered with a coverslip. A photograph using a magnification of 100X was taken of 1.02 mm2 of the leaf with a 35mm camera (Figure l). The pictures were taken of the upper leaf surface adjacent to the midrib. The film was processed and the hairs were counted on the strip print. Oviposition Test Oviposition preference of the four spring wheat varieties, CI11490, CI9321, Hope and Chris, was studied on the three leaf seedlings and the mature plants. Forty seeds of each variety were planted in one and three— quarter inch peat pots in the greenhouse. When the seeds germinated the peat pots were transplanted into six—inch clay pots. When the plants were in the three leaf stage, four plants of each variety were arranged in a randomized block design in a growth chamber at 86 F. Postdiapause adult beetles were removed from cold storage and placed in the growth chamber at 86 F. After feeding 48 hours on a susceptible barley variety, 200-unsexed beetles were placed in the cage containing the four spring varieties. After 24 hours the beetles were removed and egg counts were made on each plant. CIll490, 76 hairs CI9321, 61 hairs Hope, 27 hairs Chris, 4 hairs Figure l.--Photomicrographs of leaf samples from CIll490, CI9321, HOpe and Chris showing leaf pubescence per 1.02 mm2 (lOOX). 10 After the four spring varieties reached the heading stage the same procedures were followed to conduct the oviposition preference test. Larval Weight Gain Test Larval feeding tests were conducted on the four spring wheat varieties at two different stages of growth. The plants used in this test were from the same group of plants which were planted for the oviposition test. The first test was conducted with plants in the three leaf seedling stage. A complete block design with four repli- cations was used to conduct the experiment. Two first instar larvae less than six hours in age were placed on the third leaf and a plastic cylinder was placed around the plant to confine the larvae. The plants were placed in an environmental chamber which had a 16-hour day temper— ature of 85 F and an eight-hour night temperature of 78 F. The larvae were removed from the plants after 72 hours and the fecal matter removed from their backs. The larvae were weighed on a 0.1 mg precision torsion balance. The second larval feeding test was run on plants after heading when internode elongation and leaf develOp- ment were complete. Two first instar larvae less than six hours in age were placed on the flag leaf of the plant and confined by small leaf cages (Figure 2) which enclosed four inches of the leaf. After 72 hours of feeding the larvae were too small to weigh accurately, so they were 11 .mumww cwmm unwfim3 Hm>uma now mama moan on» :0 mm>uma umumcw uwuwm mcflmcoo ou cows woman mmmqnu.m mucmwm 12 allowed to feed another 72 hours. Again they were removed, cleaned and weighed. Oviposition and Larval‘FeedinngestS‘on Segregating_W1nter Wheat Selections Oviposition and larval feeding tests were also run on seven lines of mature winter wheat selections being developed in the wheat project at Michigan State University. The selections were fourth generation plants classified as resistant in the field last year. The selections were crosses between two highly pubescent varieties, CI9321 and C18286 and two winter wheat varieties, Genesee and Talbot. The plants were vernalized in the field and then transplanted after 12 weeks to the greenhouse. Both tests were conducted when the plants were fully elongated. Damage to Genesee Wheat To assess the damage to winter wheat caused by the cereal leaf beetle, 500 culms of Genesee winter wheat growing in Berrien County, Michigan were tagged at the soft dough stage when the flag leaf had approximately 25% damage caused by the larval feedings. At the same time 500 culms with no damage were also tagged. At maturity the heads were harvested with the seed per head and seed weight being recorded. The seed was then sent to the United States Department of Agriculture Soft Wheat Quality laboratory in Wooster, Ohio for pastry quality tests which included pearling index, flour yield, and alkaline water retention capacity tests (15). RESULTS AND DISCUSSION Pubescence Study The study of pubescence with the varieties CIll490, CI9321, Hope and Chris, is summarized in Table l. The ob- servations were averaged for the materials from the three planting dates because they showed similar trends; each statistic is the average of 27 observations. TABLE 1. Number of leaf hairs per 1.02 mm2 leaf area for the varieties CI11490, CI9321, Hope and Chris averaged over the three planting dates. Leaf Number Variety Mean 1 2 3 4 (flag) CIll490 77:6.8 77:7.5 57:6.3 75:5.2 71 CI9321 74:3.7 6916.2 58:4.6 69:6.6 68 Hope 43:3.7 5238.2 52:6.1 6415.6 53 Chris 12:1.1 1212.7 10:1.8 7:1.4 10 Mean 52 53 44 54 The highly pubescent varieties CIll490 and CI9321, exhibit similar changes in pubescence. Leaves one, two, and four (the flag leaf) are the most pubescent, l3 14 ranging from 69 to 77 leaf hairs per 1.02 mmz. The third leaves of these varieties have a lower density. Hope, the moderately pubescent variety, exhibits another pattern of pubescence. Leaves two and three have the same density while the first leaf averages nine hairs less per 1.02 mm2 and the flag leaf averages 12 hairs more per 1.02 mmz. Chris, the near glabrous variety shows yet another trend of pubescence. Leaves one and two are similar while pubescence decreases on leaves three and four. The analysis of variance shows a highly signifi- cant difference between existing leaves, varieties and dates (Table 2). The two factor interactions between leaves x varieties, leaves x dates and dates x varieties also differed significantly. TABLE 2. Analysis of variance for leaf hair density of four leaves of the spring wheat varieties CIll490, CI9321, Hope and Chris which were planted on three different dates at the same location. Source df Mean square F value Total 3 42,328.61 Leaf 3 631.75 5.53** Variety 3 28,174.25 246.82** Date 2 6,055.84 53.05** Leaf x variety 9 437.12 3.83** Leaf x date 6 1,217.30 10.66** Date x variety 6 477.11 4.18** Date x leaf x variety 18 188.76 1.65 Residual 96 114.15 15 Duncan's New Multiple Range test showed that the difference between leaves was due to the lower hair density of the third leaf. There was no significant difference be- tween the means of the other three leaves. 'The differences between varieties was expected because of the choice of varieties. There was a highly significant difference between the near glabrous variety, Chris, and the three pubescent varieties. There also was a highly significant difference between the moderately pubescent variety, HOpe, and the varieties CIll490 and CI9321. The highly significant difference in leaf pubes- cence between dates of planting could be due to the effect of the environment. Since there were three planting dates and the leaves were sampled in the three leaf stage for each planting date, plant development, including pubescence could be influenced by temperature, moisture and other environmental conditions operating during the particular growth period following a planting date. The results of both the larval weight gain and oviposition preference tests on the four spring wheat varieties in both the seedling and fully elongated stages are shown in Table 3. 16 .mm>uma m mo mmmum>m co commmm mm mm «H.Ho.~ ma.uk.a o.muaam o.auam mango ms am mm.uo.H w~.HA.o H.vHHH o.HH~ mmom am ma ha.um.a m~.Ho.H o o Hammau Am ma mm.um.o mm.H~.H «Hm o omeHHHo cmummcon mafiacmmm cmummcon mcwacmmm cmummcon mafiacmmm mmmum mmm>umq on» no .mum mh\mE ca cwmw cwmq momm mo .02 aumwuc> Hm>fl>ucm unmoumm ucmflmz Hm>umq umma cowufimomw>o .ommum cmummcoam madam can ommum mcflapmmm may anon cw mmwumflum> poms: madman Hsom nufl3 Hm>w>ucm ucwuuwm can mcwmm usmflm3 Hm>uma can and» coAuHmomfi>o .m mqmda 17 Oviposition Test The oviposition tests in both stages of plant growth showed that Chris was susceptible while CIll490, CI9321 and HOpe were resistant. The greater number of eggs laid on the adult plants may be due to the differences in the lots of beetles, as the tests were conducted at differ- ent times. Larval Weight Gain Test The larval weight gain tests showed similar re— sults. The larvae feeding on the check variety, Chris, showed a highly significant difference from those feeding on the subescent varieties in both seedlings and fully elongated plants. The percent survival of the larvae was the lowest on the two highly pubescent varieties, CIll490 and CI9321, while HOpe was a little higher and the check had the highest percent survival. There was also greater survival in the test on adult plants compared to the sur- vival on the seedlings. Oviposition and Larval Feeding Tests on Segregating_Winter Wheat Selections The results from the screening of seven winter wheat selections in the heading stage is shown in Table 4. The seven selections are fourth generation material selected at random for this experiment from 142 similar lines which showed field resistance in 1969. 18 TABLE 4. Oviposition test and larvae weight gain with two susceptible checks and seven winter selections in the heading stage with field resistance. 321322133233: Gaizrzzlm23iahsrs.a 29 (check) 180113.0 1.41.06 Genesee (check) 1321 9.9 0.91.11 174 124115.6 1.31.32 105 106118.3 0.91.08 164 801 6.4 0.61.28 101 661 5.6 1.01.15 217 57110.4 1.01.07 131 191 3.7 1.01.18 126 151 2.8 0.61.06 a Based on average of 8 larvae. There was a highly significant difference between varieties for oviposition preference and larval weight. However, much variation was noted among the seven selections and the two checks (Table 4). Selection 126 was very low in oviposition prefer- ence and larval weight gain. Selection 131 was also very low in oviposition preference, but did not differ from the checks in larval weight gain. Although selection 164 was higher in oviposition preference than selections 126 and 131, it was significantly lower than both checks for this test and significantly lower than one of the check {II-"'11. I I III-11.. \ 19 varieties in larval weight gain. Selections 101 and 217 differed significantly from the checks in only oviposition preference. Selections 174 and 105 performed similarly to the checks in all the tests. Schillinger (19) found that only 20% of the lines with field resistance were classified as resistant with larval weight gain tests. These data substantiate his results and underscore the importance of screening all selections exhibiting field resistance for oviposition preference and larval weight gain tests. It is possible that some varieties may inhibit oviposition, but lack the physical or chemical inhibitors (antibiosis) which would limit larval weight gain. Damage to Genesee Wheat The yield of Genesee winter wheat with 20-30% of the flag leaf destroyed by larval feeding was reduced 7%. There was no reduction in kernel number per head, but a 7% reduction in kernel weight (Table 5). Gallun (7) found a 12% reduction in kernel number and a 23% reduction in mean kernel weight when the flag leaf was completely con— sumed. These studies would indicate that a mild infes- tation of cereal leaf beetles would cause a reduction in only kernel weight, while a heavy infestation would reduce both kernel number and weight. There was no difference between the damaged and undamaged Genesee in the tests which measured pastry 20 TABLE 5. Kernel number, kernel weight, pearling index, flour yield, and alkaline water retention capacity tests of Genesee winter wheat with approximately 25% of the flag leaf destroyed and undamaged plants. Mean Mean Kernel Kernel Weight in Pearling Flour Micro No. g/head Index Yield AWRC Damaged Genesee 25.10 0.946 46.6 68.3 57.5 Undamaged Genesee 25.12 1.017* 49.5 69.0 57.6 *Significant at 5% level. quality; namely pearling index, flour yield, and alkaline water retention capacity. Most of the winter wheat in Michigan has fully tillered and is in the jointing stage when the beetles become active in the spring. Since the wheat seedlings have been used by the plant breeder for leaf pubescence counts, oviposition preference tests, and larval weight gain tests to isolate resistant germplasm, the question was raised whether or not this resistance is still oper; ating in the mature plant. This study positively confirms that seedling and adult plant resistance to the cereal leaf beetle are correlated. LIST OF REFERENCES LIST OF REFERENCES Afzal, M. and M. A. Ghani. 1949. Studies on the cotton jassid (ggpoasca devastans Dist.) in the Punjab. XI. E ect of agronomic factors on the incidence of jassid attack. Pakistan J. Sci. Res. 1:41-62. Carl, K. P. 1968. Investigations on the cereal leaf beetle, Oulema melanopous. Commonwealth Insti- tute of Biological Control Publication. Castro, Thomas R., Robert Ruppel, Melvin S. Gomulin- ski. 1965. Natural History of the cereal leaf beetle in Michigan. Mich. Agr. Exp. Sta. Quart. Bull. 47:623-653. Esau, K. L965. Plant Anatomy. John Wiley and Sons, Inc. New York, pp. 167-171. Everson, E. H., R. L. Gallun, J. A. Schillinger, Jr., D. H. Smith, and J. C. Craddock. 1966. Geo— graphic distribution of resistance in Triticum to the cereal leaf beetle. Mich. Agri. Exp. Sta. Quart. Bull. 48:565-569. Fahn, A. 1967. Plant Anatomy. Pergamon Press, New York, pp. 193-240. Gallun, R. L. 1965. Yield loss in Monon wheat for cereal leaf beetle feeding. Proc. N. Centr. Br. Entomol. Soc. Amer. 20:65. , R. T. Everly, and W. T. Yamazaki. 1967. YieId & milling quality of Monon wheat damaged by feeding of cereal leaf beetle. J. Econ. Entomol. 60:356-359. , R. Ruppel, and E. H. Everson. 1966. Re31stance of small grains to the cereal leaf beetle. J. Econ. Entomol. 59:827-829. 21 10. ll. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22 Lyon, William F., and D. A. Ray. 1969. Cereal leaf beetle infestation on 20 varieties of drill-seeded spring oats in Franklin County, Columbus, Ohio, 1968. Proc. N. Centr. Br. Entomol. Soc. Amer. 24:21-22. Painter, R. H. 1951. Insect resistance in crop plants. The University Press of Kansas, Lawrence. . 1958. Resistance of plants to insects. Parnell, F. R., H. E. King, and D. F. Ruston. 1949. Jassid resistance and hairiness of the cotton plant. Bull. Entomol. Res. 39:539-575. Percival, John. 1921. The wheat plant. E. P. Dutton & Co., New York. Quisenberry, K. S. and L. P. Reitz. 1967. Wheat and wheat Improvement. American Society of Agronomy, Inc., Madison, pp. 445-466. Ringlund, K. 1967. Leaf pubescence in common wheat, Triticum aestivum L., and resistance to the cereal leaf beetle, Oulema melanopus (L.), Ph.D. Thesis Michigan State Un1v., E. Lansing. and E. H. Everson. 1968. Leaf pubescence 1n common wheat, Triticum aestivum L., and re- sistance to the cereal leaf’beetle, Oulema melanopus L., Crop Sci. 8:705-710. Ruppel, R. F. 1964. Control of the cereal leaf beetle. Proc. N. Centr. Br. Entomol. Soc. Amer. 19:127-128. Schillinger, J. A. 1966. Larval growth as a method of screening Triticum sp. for resistance to the cereal leaf beetIe. J. Econ. Entomol. 59:1163— 1166. . 1967. The relationship of pubescence to re31stance in wheat to the cereal leaf beetle, Oulema melanopus L. Proc. N. Centr. Br. Entomol. S56. Amer. 22:98. . 1969. Three laboratory techniques for screening small grains for resistance to the cereal leaf beetle. J. Econ. Entomol. 62:360-363. 22. 23. 24. 25. 26. 27. 23 Schillinger, J. A., and R. L. Gallun. 1968. Leaf pubescence of wheat as a deterrent to the cereal leaf beetle, Oulema melanopus. J. Econ. Entomol. 61:900-903. Shade, R. E., and M. C. Wilson. 1969. Oviposition of the cereal leaf beetle. Proc. N. Centr. Br. Entomol. Soc. Amer. 24:22. Steel, Robert G. D., and James H. Torrie. 1960. Principles and procedures of statistics. McGraw- Hill Book Co., Inc., New York. Wellso, Stanley G., James A. Webster, and Robert F. Ruppel. A Bibliography of the cereal leaf beetle, Oulema melanopus L. (Coleoptera: Chrysomelidae). (In press). Wilson, Curtis M., and Richard E. Shade. 1964. The influence of various Gramineae on weight gains of postdiapause adults of the cereal leaf beetle, Ouelema melano a (Coleoptera: Chrysomelidae). Ann. Entomo . Soc. Amer. 57:659-661. Yun, Y. Mok. 1965. Some effects of environment on the cereal leaf beetle. Proc. N. Centr. Br. Entomol. Soc. Amer. 20:65. APPENDI X 24 TABLE 6. Duncan's New Multiple Range Test comparing the four different leaves of four spring wheat varieties, CIll490, CI9321, Hope and Chris. Range of Means Being Tested Significant differences at 2 3 4 .01 level of significance 6.41 6.68 6.90 Leaves Difference 4-3 = 10 > 6.90** 4-1 = 2 < 6.68 2-3 = 9 > 6.68** 1-3 = 8 > 6.41** TABLE 7. Duncan's New Multiple Range Test comparing four spring wheat variety means. Range of Means Being Tested Significant differences at 2 3 5 .01 level of significance 6.41 6.68 6.90 Variety Difference CI11490-Chris = 61 > 6.90** CIll490-H0pe = 18 > 6.68** CI11490-CI9321 = 3 < 6.41 CI9321-Chris = 58 > 6.68** CI9321-Hope = 15 > 6.41** Hope-Chris = 43 > 6.41** 25 TABLE 8. Analysis of variance table for oviposition test on 3 leaf seedlings of four spring varieties, CIll490, CI9321, Hope and Chris. Source df Mean Square F Total 15 Block 3 7.77 Varieties 3 158.33 6.2* Error 9 25.56 TABLE 9. Analysis of variance table for oviposition test on fully developed spring wheat varieties, CIll490, CI9321, HOpe and Chris. Source df Mean Square F Total 15 Block 3 120.67 Varieties 3 8,316.75 47** Chris vs.: CIll490 CI9321 1 24,934.08 l39.8** Hope Error 9 179.06 26 TABLE 10. Analysis of variance table for larval weight gain on 3 leaf seedlings of four spring varieties, CIll490, CI9321, Hope and Chris. Source df Mean Square F Total 15 Block 3 0.20 Varieties 3 2.05 8.0* Chris vs.: CI11490 CI9321 l 6.00 23.0** Hope Error 9 0.256 TABLE 11. Analysis of variance table for larval weight gain on fully deve10ped plants of four spring varieties, CIll490, CI9321, HOpe and Chris. Source df Mean Square F Total 15 Block 3 0.15 Varieties 3 9.19 7.79* Chris vs.: CIll490 C19321 1 19.51 16.0** HOpe Error 9 1.18