1977 Research Report MONTCALM EXPERIMENT STATION Michigan State University Agricultural Experiment Station ACKNOWLEDGMENTS Research personnel working at the Montcalm Branch Experiment Station have received much assistance in various ways. A special thanks is due each of these individuals, private companies and government agencies who have made this research possible. Many valuable contributions in the way of fertilizers, chemicals, seed, equipment, technical assistance, personal services, and monetary grants were received and are hereby gratefully acknowledged. Special recognition is given to Mr. Theron Comden for his devoted cooperation and assistance in many of the day-to-day operations and personal services. Foliar fungicide and insecticide sprays were applied with a new FMC side boom sprayer. The sprayer was purchased by the Michigan Potato Industry Commission and donated to Michigan State University and the Montcalm Experimental Farm for research use. Appreciation for this support is hereby gratefully acknowledged. TABLE OF CONTENTS Page INTRODUCTION, WEATHER AND GENERAL MANAGEMENT. . . ...................................... . . . 1 Integrated Project - Influence of Selected Production Management Inputs on the Yield, Quality, Storability of Russet Burbank, Onaway and Superior Potatoes Nematology Component G.W. Bird..................................................................................................................................................4 Fertility Component M L. Vitosh. ........................ 11 Insect Component Arthur L. Wells and Mark Otto................................................................................................20 Variety and Seedling Evaluation N. R. Thompson, R.W. Chase and R.B. Kitchen........................................................................23 Influence of Experimental Nematicides on Control of Root-Lesion Nematodes and Potatoes Yields G. W. Bird.....................................................................................................................................................27 Soil Insect Research - 1977 Arthur L. Wells and Mark Otto.....................................................................................................29 Population Growth and Seasonal Development of Colorado Potato Beetle Cynthia K. Blakeslee...............................................................................................................................35 Potato Seed Treatment Trials H. Spencer Potter................................................................................................................................................35 Dry Bean Nematicide Trials G.W. Bird....................... 38 Corn Hybrids, Plant Population and Irrigation E.C. Rossman and Bary Darling........................................................................................... 40 MONTCALM BRANCH EXPERIMENT STATION RESEARCH REPORT R.W. Chase and M.H. Erdmann, Coordinators Department of Crop and Soil Sciences INTRODUCTION The Montcalm Branch Experiment Station was established in 1966 with the first experiments initiated it 1967. This report marks the completion of ten years of studies. The 40-acre facility is leased from Mr. Theron Comden and is located in west-central Michigan, one mile west of Entrican. The farm is used primarily for research on potatoes and is located in the heart of a major potato producing area. This report is designed to coordinate all of the research obtained at this facility during 1977. Much of the data herein reported represents projects in various stages of progress; so results and interpretations may not be final. RESULTS PRESENTED HERE SHOULD BE TREATED AS A PROGRESS REPORT ONLY as data from repeated trials are necessary before definite conclusions and recommendations can be made. WEATHER Tables 1 and 2 summarize the 10 year temperature and rainfall data. With­ out question, weather during the 1977 growing season was the most unusual me have experienced during our tenure at the research farm. The average maximum temperatures for April and May were well above the ten year average with May being 13° higher. Maximum temperatures for the balance of the growing season were more nearly normal. There was little deviation from the 10 year average of the minimum temperature. In May there were 6 days with a maximum temperature above 90°F and 13 days when it exceeded 85°F. The rainfall distribution was very erratic also. Less than one-half inch rain was recorded in May which is far below the 3.08 ten year average. Similarly, April and June were substantially below the average which resulted in the driest initial growing season we have experienced. At the other extreme, September rainfall was more than twice the 10 year average which interfered with intended harvests, however, all harvests were competed before the first freeze which occurred on October 7. Irrigation applications of approximately one inch each were made 13 times (June 17, 24, July 3, 11, 18, 22, 25, 29, August 2, 9, 16, 21 and 26). SOIL TESTS Soil test results for the general plot area were: Pounds per Acre Pounds per Acre Pounds per Acre Pounds per Acre pH P K Ca 6.4 459 216 1,011 Mg 142 Table 1. The 10-year summary of recorded maximum and minimum temperatures during the growing season at the Montcalm Branch Experiment Station. Year April Max April Min May Max May Min June Max June Min July Max July Min August Max August Min September Max September Min 6-month average Max 6-month average Min 61 56 54 53 47 54 57 48 58 62 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 10-year average 55 37 35 35 31 30 36 36 28 35 37 34 62 67 65 65 70 63 62 73 63 80 67 41 43 47 39 47 42 41 48 41 47 44 74 70 72 81 72 77 73 75 79 76 75 53 50 55 56 50 58 52 56 57 50 54 80 80 80 82 79 79 81 80 81 85 81 55 59 60 55 57 60 57 57 58 61 81 82 80 80 76 80 77 79 80 77 58 79 58 56 57 53 57 60 56 58 53 52 56 74 73 70 73 69 73 68 65 70 70 71 50 49 51 54 49 48 45 44 46 53 49 73 74 73 76 73 74 70 70 71 75 empty table cell 50 49 45 48 48 51 48 49 48 50 empty table cell Table 2. The 10-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Station. Year April May June July August September Total 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 10-year average 2.84 3.33 2.42 1.59 1.35 3.25 4.07 1.81 3.27 1.65 2.56 4.90 3.65 4.09 0.93 1.96 3.91 4.83 2.05 4.03 0.46 3.08 3.74 6.18 4.62 1.50 2.51 4.34 4.69 4.98 4.22 1.66 3.84 1.23 2.63 3.67 1.22 3.83 2.36 2.39 2.71 1.50 2.39 2.39 1.31 1.79 6.54 2.67 7.28 3.94 6.18 11.25 1.44 2.61 4.50 3.30 0.58 7.18 4.00 2.60 1.33 1.81 3.07 1.40 8.62 3.39 17.32 18.16 28.52 11.91 19.53 19.13 23.97 25.87 15.86 17.39 19.8 FERTILIZERS USED Except for the specific fertility studies where the fertilizers are specified in the report, the following fertilizers were used on the potato plot area: Plow down Banded at planting - 12-12-12 Sidedressed at hilling Fall seeded rye plowed down - 0-0-60 - 200 - 600 lbs/A lbs/A - 46-0-0 - 300 lbs/A HERBICIDES Preemergence - metribuzin (Sencor) 1/2 lb/A + alachlor (Lasso) 2 qts/A DISEASE & INSECT CONTROL The systemic insecticide Temik was applied at planting at 3 pounds per acre. Foliar fungicide and insecticide sprays were as follows: July 5 July 11 July 26 August 5 August 13 August 20 August 29 September 6 Bravo + Thiodan Bravo + Monitor Bravo Bravo + Metasystox-R Bravo + Thiodan Bravo + Thiodan Bravo Bravo Integrated Project - Nematology Component INFLUENCE OF SELECTED PRODUCTION MANAGEMENT INPUTS ON THE YIELD, QUALITY, STORABILITY OF RUSSET BURBANK, ONAWAY AND SUPERIOR POTATOES G. W. BIRD Department of Entomology Four pesticide treatments (Check, DiSyston 15G, Temik 15G and Vorlex plus DiSyston 15G), three nitrogen levels (70, 150, and 30 lb/acre) and three potato cultivars were used to evaluate the combined influence of pesticides and nitrogen on potato growth and development, associated pest population dynamics and potato yields. The three cultivars were planted in separate, but adjacent ranges at the M.S.U. Montcalm Potato Research Farm. Each treatment was replicated four times in a randomized block design. Each plot consisted of four rows 50 feet in length and 34 inches apart. Vorlex was injected to a soil depth of 6-8 inches in a broadcast manner on April 21, 1977. The other pesticides were applied at planting on May 9-10, 1977. All plant growth and development measurements and nematode population dynamics samples were taken from the outside two rows of each plot. Yield data were taken by harvesting of center two rows of each plot. DiSyston, Temik and Vorlex significantly (P=0.05) increased yields of Superior potatoes at all nitrogen rated (Table 1). The greatest yield, however, was with Temik at the 150 lb. nitrogen rate. Yields of Onaway were not enhanced as much as those of Superior by the pesticides. With Russett Burbank, only the Vorlex treat­ ment at the 300 lb. nitrogen rate resulted in a significant increase in yield. The results were similar, but more pronounced when the data were analyzed for the pesti- cides without respect to the nitrogen treatments (Table 2). Increasing the nitrogen rate had no influence on the yield of any of the cultivars (Table 3). Both Temik and Voolex gave good control of root-lesion nematodes associated with all three cultivars (Tables 4-6). The nitrogen rates had no influence on the nema­ tode control associated with any of the three cultivars. DiSyston application resulted in approximately 20% nematode control. The growth and development of the shoot systems, root systems and tubers progressed throughout the growing season, reflecting early nematode control and enhanced growth and development. The results of this investigation are similar to those obtained for nematode control studies on soil in Michigan in the past. They reflect the fact that cv Superior is highly susceptible to root-lesion nematode damage, and that Russet Bur­ bank is tolerant. Economic losses, however, can occur with this cultivar. Onaway is in an intermediate category. The population dynamics information is similar to that obtained in 1976. Population development was considerable earlier. This was probably due to the warm temperatures in May. All of the data will be plotted using a physiological base as a substitute for calendar days. This will make it possible to compare the 1977 and 1978 data. Better evidence of root-lesion nematode control with Vorlex would have been obtained if soil and root samples were taken between planting and June 15. Earlier nematode control with Temik may have been prevented because of the ex­ tremely dry conditions at the time of planting. This factor may have resulted in lower yields with this treatment than if it had been applied under more op­ timal environmental conditions. For the second year, season-long nematode control was obtained with Temik. This is the first report of this! It may be that it has been overlooked because of the way nematologists make their obser­ vations. A limited amount of root-lesion nematode control with DeSyston should have been expected. The results of the foliage analysis is in general agreement with the way plant-parasitic nematodes cause diseases of most crops. Table 1. Influence of nitrogen and pesticides on yields of three potato cultivars Treatment Yield (ctw/A) Yield (ctw/A) Superior Onaway (ctw/A)Russet Burbank Yield N (75 lb/A) Check DiSyston (3.0 lb/A) N (75 l b/A) Temik (3.0 lb/A) N (75 l b/A) Vorlex (10 gal/A) N (75 l b/A) N (150 lb/A) Check DiSyston (c.0 lb/A) N (150 l b/A) Temik (3.0 lb/A) N (150 l b/A) Vorlex (10 lb/A) N (150 l b/A) N (300 lb/A) Check DiSyston (3.0 lb/A) N (300 l b/A) Temik (3.0 lb/A) N (300 l b/A) Vorlex (10 gal/A) N (300 l b/A) 119a1 166bc 172bc 183bc 105a 152bc 196c 189bc 86a 139b 174bc 179bc 140a 177b 174ab 199bc 174ab 172ab 211bc 203bc 143a 172ab 193bc 214c 200a 236ab 211ab 256ab 213ab 229ab 243ab 245ab 194a 223ab 249ab 270b 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test Table 2. Influence of three pesticides on yields of three potato cultivars Pesticide Yield (ctw/A) Superior Yield (ctw/A) Onaway Yield (ctw/A) Russett Burbank Check DiSyston (3.0 lb/A) Temik (3.0 lb/A) Vorlex (10 gal/A) 111a1 152b 180c 183c 152a 174b 193c 206c 203a 229b 231b 257c 1Column means followed by the samle letter are not significantly different (P=0.05) according to the Student Newman-Keuls Multiple Range Test. Table 3. Influence of three levels of nitrogen on yields of three potato cultivars N level Yield (ctw/A) Superior Yield (ctw/A) Onaway Yield (ctw/A) Russett Burbank 75 lb/A 150 lb/A 300 lb/A 160a1 160a 149a 172a 189b 183ab 226a 232a 232a 1 Column means followed by the same letter are not significantly different according to the Student-Newman-Keuls Multiple Range Test. Table 4. Influence of pesticides on population densities of root-lesion nematodes associated with "Superior" potatoes. Treatment 3 soil 4/14 Root-lesion nematodes/100 cm Root-lesion nematodes/100 cm 3 soil 6/15 3 soil 9/22 Root-lesion nematodes/100 cm Root-lesion nematodes/100 cm 3 soil 6/30 Root-lesion nematodes/100 cm 3 soil 8/1 Root-lesion nematodes/100 cm 3 soil 8/8 Root-lesion nematodes/100 cm 3 soil 7/18 Root-lesion nematodes/g root 7/18 6/15 Root-lesion nematodes/g root Root-lesion nematodes/g root 7/30 Root-lesion nematodes/g root 8/1. 8/8 Root-lesion nematodes/g root Check DiSyston Temik (3.0 lb/A) Vorlex (10 gal/A) 43a 35a 24a 28a 28a 37a 25a 22a 3ab 13b 0a 5ab 10a 23b 5a 8a 58a 32b 7b 20b 13a 25a 10a 13a 67a 57a 5b 20b 43a 45a 5a 30a 163a 130a lb 145a 183a 60a 110a 30ab 57ab 8b 8b 78ab 82ab 38ab 0b 26b 1 Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test. Table 5. Influence of pesticides on population densities of root-lesion nematodes associated with "Onaway" potatoes Treatment Check DiSyston (3.0 lb/A) Temik (30 lb/A) Vorlex (10 gal/A) Root-lesion nematodes/100 cm3 soil 4/14 40a1 30a 29a 29a Root-lesion nematodes/100 cm 3 soil 6/15 Root-lesion nematodes/100 cm 3 soil 9/22 3 soil 6/30 Root-lesion nematodes/100 cm Root-lesion nematodes/100 cm 3 soil 8/1 Root-lesion nematodes/100 cm 3 soil 8/8 Root-lesion nematodes/100 cm 3 soil 7/18 6/15 Root-lesion nematodes/g root 7/30 Root-lesion nematodes/g root 8/8 Root-lesion nematodes/g root Root-lesion nematodes/g root 7/18 Root-lesion nematodes/g root 8/1 28a 23a 38a 30a 17a 22a 17a 15a 18a 28a 8ab 2b 5ab 8ab 2b 11ab 5a 5a 8a 8a 5a 5a 0a 10a 26ab 33b 7a 26ab 195a 148a 25b 65b 187a 177a 28b 70a 48a 25a 2b 27a 36a 16a 3a 27a 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student- Newman-Keuls Multiple Range Test. Table 6. Influence of pesticides on population densities of root-lesion nematodes associated with "Russet Burbank" potatoes. Treatment Root-lesion nematodes/100 cm 3 soil 8/8 3 soil 4/14 Root-lesion nematodes/100 cm Root-lesion nematodes/100 cm 3 soil 6/30 3 soil 7/18 Root-lesion nematodes/100 cm 3 soil 6/15 Root-lesion nematodes/100 cm 3 soil 8/25 Root-lesion nematodes/100 cm 3 soil 9/22 Root-lesion nematodes/100 cm Root-lesion nematodes/g root 7/18 Root-lesion nematodes/g root 6/15 Root-lesion nematodes/g root 8/1 Root-lesion nematodes/g root 6/30 8/8 Root-lesion nematodes/g root Root-lesion nematodes/g root 8/25 Check 55a1 DiSyston (3.0 lb/A) 30a Temik (3.0 lb/A) Vorlex (10 gal/A) 51a 29a 27a 32a 17a 27a 18a 7a 7a 12a 12a 15a 5a 7a 7a 10a 3a 8a 32a 25a 0b 22a 50a 27a 30a 37a 48a 37a 6b 36a 110a 83a 2b 75a 210a 115a 17b 100a 73a 67a 8b 42a 195a 40a 162a 23ab 12b 120a 7b 38a 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student- Newman-Keuls Multiple Range Test. Integrated Project-Fertility Component INFLUENCE OF SELECTED PRODUCTION MANAGEMENT INPUTS ON THE YIELD, QUALITY, STORABILITY OF RUSSET BURBANK, ONAWAY AND SUPERIOR POTATOES M. L. Vitosh Department o£ Crop and Soil Science This project was a study conducted as part of an overall project to look at insects, nematodes, nitrogen and varieties and the interactions which might occur. Only the nutritional aspect is reported on here. Information on other apsects are reported by Dr. G.W. Bird. Influence of nitrogen on elemental composition of potato petioles. Table 1 which shows the overall averages of three varieties, four insecticide treatments and four replications, shows that increasing rates of N increased nitrogen (N), phosphorus (P), manganese (Mn) and copper (Cu) of the petioles. The same observations are seen in Table 2 for the Russet Burbank variety when data were averaged over two sampling dates. In addition zinc (Zn) was increased by increasing N rates. In Table 3, 300 lbs N/A decreased the magnesium (Mg) content for the Superior variety while increasing it for the Russet Burbank variety. The iron content of Superior petioles was significantly increased by 300 lbs N/A over the 75 lb N treatment (Table 4). The iron (Fe) content of the other two varieties was unaffected by N fertilizer. In Table 6, the Russet Burbank variety shows a higher potassium (K) content in petioles than in the Superior variety at the 300 lb N rate. Influence of insecticides on elemental composition of potato petioles. Values in the center of Table 1 represent averages for three varieties, three nitrogen rates and four replications for petiole samples taken July 14. The following observations were significantly different when compared to the check. (a) Temik increased N, P and Mg (b) Temik and Vorlex decreased Mn (c) Vorlex increased Mg Table 2 shows the effect of insecticides on the Russet Burbank variety when averaged over two sample dates, three rates of nitrogen and four replications. When compared with the check the following observations were significantly different. (a) Temik and Vorlex increased N (b) Temik reduced Ca and Zn (c) DiSyston reduced Cu and Zn (d) Temik increased Cu Table 3 shows three treatment interactions for magnesium. The following observations when compared to the check were significantly different for the insecticide, N rate and variety interactions. (a) Temik and Vorlex increased Mg at the 75 (b) None of the insecticides affected Mg at and 300 lb N rates 150 lb N rate (c) DiSyston increased Mg at 300 lb N rate (d) Temik and Vorlex increased Mg for the Onaway and Superior varieties Although the analysis of variance indicated a significant interaction between variety and insecticides for N, the differences were entirely related to N content of the varieties (Table 5) and not due to insecticide treatments. A look at how insecticides affected the elemental competition of potato petioles receiving only 75 lbs of N can be found in Table 7. For the Superior variety, K, Mn, Fe and Cu were significantly affected by the insecticides. Only Mn was significantly affected by insecticides for the Onaway and Russet Burbanks varieties. The overall averages for the three varieties indicates that Temik and Vorlex significantly increased Mg and decreased Mn. Correlation of yield with elemental composition of potato petioles. Simple correlation coefficients were determined comparing all elements in petioles for the July 14 sampling date with total potato yield. Nitrogen (r = .379) and Mn (r = -.405) were highly correlated with Russet Burbank yields. Aluminum (AL) (r = -.294) and Calcium (Ca) (r = .236) were also related to yield at a lower level of significance. For the Onaway variety; Al (r -434), N (r = .310) and Mg (r = .341) were significantly correlated. Significant correlations for the Superior variety were; Al (r = -.654) Fe (r = -.511) and Mn (r = -.320). Summary Nitrogen fertilizer consistently increased the N, P, Mn and Cu content of potato petioles. insecticides consistently decreased the manganese content of petioles. Temik and Vorlex usually had more effect than DiSyston for decreasing Mn. Aluminum and manganese were found to be negatively correlated with total yields. Further studies are needed to characterize the effect of insecticides on manganese uptake. Many of the manganese levels in this study were above the plant sufficiency range approaching the toxicity range. Any treatments which reduce the uptake of Mn on acid sandy soils should be valued as beneficial to plant growth. Table 1. Elemental composition of potato petioles for three varieties as affected by nitrogen rate and insecticide treatments. Treatments Elements N % P% Elements Elements K % Elements Elements Ca% Mg % Mnppm Elements Feppm Elements Elements Cu Znppm Elements ppm N-Rate 75 150 N-Rate N-Rate 300 LSD (.05) N-Rate Insecticide Check DiSyston Insecticide Insecticide Temik Insecticide Vorlex LSD (.05) Insecticide Variety Superior Onaway Variety Variety Russet Burbank LSD (.05) Variety 2.13 2.26 2.29 (.06) 2.17 2.22 2.28 2.23 (.07) 2.21 1.88 2.59 (.11) .21 .23 .23 (.01) .22 .22 .24 .21 (.02) .19 .17 .31 (.03) 8.30 8.06 8.04 (ns) 8.20 8.18 8.09 8.06 (ns) 7.71 8.04 8.64 (.46) .99 1.01 1.00 (ns) 1.01 .99 1.03 .97 (ns) 1.04 1.24 .73 (.04) .64 .63 .64 (ns) .60 .63 .65 .67 (.04) .54 .76 .62 (.07) 168 204 224 (17) 227 211 207 149 (20) 173 210 214 (14) 78 82 87 (ns) 89 79 82 79 (ns) 80 94 73 (11) 10 11 11 (1) 11 10 11 11 (ns) 10 10 12 (1) 33 37 37 (ns) 34 32 39 37 (ns) 31 30 46 (7) Table 2. Elemental composition of potato petioles for the Russet Burbank variety as affected by nitrogen rate, insecticide treatment and date of sampling. Treatment Elements N % P% Elements Elements K% Elements Ca% Mg% Elements Mnppm Elements Elements Feppm Cu Elements Znppm Elements N-Rate 75 N-Rate 150 N-Rate 300 LSD (.05) N-Rate Insecticide Check DiSyston Insecticide Temik Insecticide Insecticide Vorlex LSD (.05) Insecticide Sample Date 7-14-77 8- 9-77 Sample Date LSD (.05) Sample Date 2.41 2.55 2.74 (.13) 2.51 2.50 2.61 2.67 (.10) 2.59 2.55 (ns) .28 .31 .36 (.03) .32 .30 .33 .32 (ns) .31 .32 (ns) 7.89 7.59 7.60 (ns) 7.80 7.62 7.68 7.67 (ns) 8.64 6.74 (.38) .75 .82 .77 (ns) .82 .80 .78 .71 (.06) .73 .83 (.06) .70 .75 .72 (.06) .74 .71 .73 .71 (ns) .61 .83 (.08) 281 363 418 (37) 403 390 350 274 (43) 214 494 (57) 74 77 81 (ns) 83 73 76 76 (ns) 73 81 (ns) ppm 10 11 13 (1) 11 10 12 11 (1) 12 11 (ns) 36 42 48 (3) 44 38 45 40 (4) 46 37 (3) Table 3. Magnesium content of potato petioles as affected by three treatment interactions. Insecticide Treatments Insecticide Treatments DiSyston Insecticide Treatments Temik Insecticide Treatments Vorlex% Mg Check % Mg % Mg % Mg Varieties Onaway % Mg Varieties Superior Varieties Russet Burbank % Mg % Mg empty table cell N-Rate 75 N-Rate 150 N-Rate 300 .59 .65 .56 .61 .61 .66 .66 Variety Superior Onaway Variety Variety Russet Burbank .47 .68 .64 .54 .75 .60 .67 .64 .57 .79 .61 .69 .63 .68 LSD (.05) = .07 .56 .81 .63 LSD (.05) = .09 .53 .52 .55 empty table cell empty table empty cell table cell .80 .75 .71 empty table cell empty table empty cell table cell .58 .62 .65 LSD (.05) = .07 empty table cell empty table empty cell table cell Table 4. Iron content of potato petioles as affected by a variety x nitrogen treatment interaction. Variety Superior Onaway Russet Burbank N Rate (lbs/A) 75 ppm Fe N Rate (lbs/A) N 150 Rate (lbs/A) 300ppm Fe ppm Fe 68 97 69 79 95 71 92 89 80 LSD (.05) = 16 Table 5. Nitrogen content of potato petioles as affected by a variety x insecticide interaction. Variety Insecticide Check % N Insecticide Insecticide Temik DiSyston% N Vorlex% N Insecticide % N Superior Onaway Russet Burbank 2.19 1.82 2.51 2.27 1.80 2.58 2.27 1.97 2.60 2.12 1.91 2.66 LSD (.05) = .16 Table 6. Potassium content of Potato Petioles as affected by a variety x nitrogen interaction. Variety Superior Onaway Russet Burbank N Rate (lbs/A) N Rate (lbs/A) 150% K 75% K 8.00 8.00 8.90 7.73 7.78 8.65 N Rate (lbs/A) 300 % K 7.40 8.35 8.38 LSD (.05) = .61 Table 7. Elemental composition of potato petioles for three varieties at the low nitrogen rate as affected by insecticide treatments. Insecticide Treatment Elements N % Elements P % Elements K % Elements Ca % Elements Mg % Elements Mn ppm Elements Fe ppm Elements Cu ppm Elements Zn ppm Superior Superior Superior Superior Superior Superior Superior Superior Superior Superior Check DiSyston Temik Vorlex LSD (.05) Onaway 2.08 2.16 2.04 2.00 (ns) .16 .18 .20 .16 (ns) Onaway Onaway 7.32 8.72 8.15 7.80 (.70) Onaway 1.75 1.88 1.82 1.70 (ns) 8.09 8.04 8.04 7.80 (ns) Check DiSyston Temik Vorlex .74 .80 .81 .86 (ns) Russet Burbank Russet BurbankRusset BurbankRusset Burbank Russet Burbank .56 Check .54 DiSyston .63 Temik Vorlex .60 (ns) Overall Average Overall Average .59 .61 .67 .69 (.07) Overall Average Overall Average Check DiSyston Temik Vorlex 9.47 8.64 8.75 8.73 (ns) 2.46 2.50 2.52 2.66 (ns) 2.10 2.18 2.12 2.12 (ns) .99 .99 1.04 .94 (ns) .70 .66 .73 .64 (ns) .16 .18 .16 .16 (ns) .30 .28 .30 .31 (ns) .20 .21 .22 .21 (ns) 8.29 8.47 8.32 8.11 (ns) Overall Average LSD (.05) LSD (.05) LSD (.05) .46 .50 .57 .60 (ns) .98 .99 1.19 .95 (ns) 160 167 164 85 (52) Onaway OnawayOnaway 215 228 176 125 (49) 1.30 1.33 1.21 1.24 (ns) 74 59 77 62 (12) Onaway 100 108 84 98 (ns) 8 8 11 8 (2) 24 21 27 49 (ns) Onaway Onaway 10 10 10 11 (ns) 28 32 28 26 (ns) Russet Burbank Russet BurbankRusset BurbankRusset BurbankRusset Burbank 42 39 44 40 (ns) Overall Average Overall Average Overall Average Overall Average 10 10 13 10 (ns) 59 68 80 70 (ns) 229 189 171 108 (36) Overall Average 201 195 171 106 (24) 78 79 80 77 (ns) 9 10 11 10 (ns) 31 31 33 38 (ns) Integrated Projet - Insect Component INFLUENCE OF SELECTED PRODUCTION MANAGEMENT INPUTS ON THE YIELD, QUALITY, STORABILITY OF RUSSET BURBANK, ONAWAY AND SUPERIOR POTATOES Arthur L. Wells and Mark Otto Department of Entomology The foliar insect populations on the plots in the integrated project were monitored to determine the efficacy of the systemic insecticides and when foliar applications would be needed. The plots were first sampled on June 27 by taking 10 sweeps on the foliage with an insect net on each of the four replications of each variety. The samples were then tabulated and although other insects were present their low numbers are not included here with the data on the potato leafhopper and Colorado potato beetle which are presented in Tables 1 and 2. Since the counts indicated popu­ lations of both insects were highest on the untreated plots it was decided to apply a foliar insecticide on July 5. Applications were then made on all of the plots on July 11 and the insects sampled again on July 15. At this time only the check plots had any significant numbers of potato beetles which had probably emerged after the foliars had been applied. Samples were taken from the Burbanks on July 27 at which time the potato beetle adults were lowest on the Temik treated plots. The foliage on the other varieties was nearing maturity so sampling was discontinued. The plots were sprayed again on August 5 and the Burbanks only on August 13 and 20. The treatments and dates of application are summarized in Table 1. The harvest dates and data are presented in the previous report so are not repeated here. Summary The data indicate the value of the systemic treatments on early leaf­ hopper reproduction since only the untreated plots had any significant numbers of nymphs. These did not develop after the spray treatments were started. Only the Temik treatments reduced the numbers of first generation potato beetle larvae on the plots. The early control is reflected in the adult numbers in July after the spray program had started. Table 1. Seasonal Development of Potato Leafhopper Populations on the Potato Varieties in the Integrated Project Superior Superior Onaway June Onaway Superior June 27 June 27 July 15 15 Superior June 27 Onaway 27 15 Onaway July July 15 27 Russet Burbank June June 27 Russet Burbank July 15 27 Russet Burbank July July 27 Russet Burbank Russet Burbank Russet Burbank July 15 Plot Treatments* (50 lb N) Adult (50 lb N) Nymph** (50 lb N) Adult Nymph (50 lb N) (50 lb N) Adult Nymph (50 lb N)(50 lb N) Nymph Adult Adult (50 lb N) (50 lb N) (50 lb N) Adult Nymph Nymph (50 lb N)(50 lb N) (50 lb N) Nymph Adult (50 lb N) (50 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston (150 lb N) 4 0 1 24 1 0 1 0 (150 lb N) (150 lb N) 1 2 0 0 0 0 10 2 0 21 0 0 1 1 0 0 0 0 45 4 5 0 0 0 1 4 0 0 0 0 0 0 (150 lb N)(150 lb N)(150 lb N) (150 lb N)(150 lb N) (150 lb N)(150 lb N) (150 lb N)(150 lb N)(150 lb N) 0 0 3 4 0 0 4 0 0 1 0 0 0 0 0 0 (150 lb N)(150 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston 19 0 0 0 19 3 2 5 2 0 0 3 0 0 0 0 13 0 0 1 23 2 0 0 2 2 1 2 0 0 0 0 7 6 2 5 0 0 0 0 3 3 0 3 0 0 0 0 2 0 0 0 0 0 0 0 (300 lb N) (300 lb N) (300 lb N) (300 lb N)(300 lb N)(300 lb N) (300 lb N)(300 lb N) (300 lb N)(300 lb N) (300 lb N)(300 lb N)(300 lb N) (300 lb N)(300 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston 2 0 0 2 30 1 0 7 0 3 0 0 0 0 0 0 13 1 1 2 28 1 0 1 0 0 0 0 0 0 0 0 15 8 1 3 0 0 0 0 4 2 0 2 0 0 0 0 2 3 0 0 0 0 0 0 *Granular treatments applied in fertilizer band at planting (rates based on 34 in. rows). Insecticide foliar sprays applied to the plots at recommended rates as follows: July 5 (Check plots only) - Thiodan; July 11 - Monitor; Aug. 5 - MetaSystox R; Aug. 13 - Thiodan (Burbanks only); Aug. 20 - Thiodan (Burbanks only). **Total insects per 40 sweeps (10 per replication) on each sampling date. Table 2. Seasonal Development of Colorado Potato Beetle Populations on the Potato Varieties in the Integrated Project Superior Superior Onaway June Onaway Russet Burbank Russet Burbank July SuperiorJune 27 June 27 July 15 15 Superior July 27 Onaway June 27 July 15 Onaway July June 27 Russet Burbank 27 Russet Burbank June July 15 15 July 27 27 Russet Burbank July Russet Burbank Plot Treatments* (50 lb N) Larva** Adult (50 lb N) (50 lb N) Adult (50 lb N) Larva (50 lb N) Adult Larva (50 lb N)(50 lb N) Larva 15 Adult Adult (50 lb N) (50 lb N) (50 lb N) Larva Adult (50 lb N) (50 lb N) Adult Larva Larva (50 lb N) (50 lb N) (50 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston (150 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston (300 lb N) Check Disyston 15G 3 lb Temik 15G 3 lb Vorlex + Disyston 0 1 0 0 53 19 0 27 17 9 0 3 2 3 0 0 (150 lb N) (150 lb N) (150 lb N) (150 lb N) 1 0 0 0 19 32 0 39 8 11 0 10 4 2 0 5 (300 lb N) (300 lb N) (300 lb N) (300 lb N) 0 1 0 0 73 29 1 27 10 6 0 16 1 3 0 1 0 0 0 1 1 0 0 0 0 0 0 0 75 8 0 26 (150 lb N)(150 lb N)(150 lb N) 60 14 2 13 (300 lb N)(300 lb N)(300 lb N) 48 15 0 10 26 3 0 12 13 2 0 5 5 6 0 2 1 0 0 0 0 0 0 0 5 21 0 14 1 0 0 0 0 12 0 1 6 24 2 5 10 2 0 0 (150 lb N)(150 lb N) (150 lb N)(150 lb N) (150 lb N)(150 lb N) (150 lb N) 0 1 0 1 0 0 0 0 61 17 0 24 5 0 0 0 0 0 0 8 13 18 2 19 10 0 0 3 (300 lb N)(300 lb N) (300 lb N)(300 lb N) (300 lb N)(300 lb N) (300 lb N) 0 2 0 0 0 0 1 0 67 5 0 14 26 3 0 2 2 5 0 6 16 24 4 33 5 1 0 3 *For insecticide rates and application data refer to Table 1. **Total insects per 40 sweeps (10 per replication) on each sampling date. VARIETY AND SEEDLING EVALUATIONN. R. Thompson, R. W. Chase and R. B. Kitchen Department of Crop and Soil Sciences Six replications of sixteen varieties and advanced seedlings were planted at the Montcalm Experimental Farm on May 3 in three complete blocks. A block was then harvested on August 9, September 1 and September 27 to determine the stage of growth at which economical marketable yields could be produced. Dry weather with high temperatures at planting time and throughout much of the growing season adversely affected both yield and quality. The abnormally high rainfall in September delayed the last harvest date. While yields were lower than in 1976 both Atlantic and AK 37-19 produced the highest yields and highest solids at the August 9 harvest. Both varieties made good potato chips. In the later harvests Katahdin and the seedlings A 6789-7, Ms 711-8 and Ms 706-34 produced the high yields. All are good general purpose table varieties. In the seedling trials, yields of the very early selections were much lower than in 1976. Eighteen of the thirty-eight seedlings continued to make good chips and demonstrated their potential as chipping varieties. Many of the new introductions have a golden flesh color which makes a most attractive chip. Cooking trials, where cultivars are evaluated for general culinary qualities, mealiness, after cooking darkening, etc. will be competed in January. All potential chip varieties will be reconditioned from 40° storage and chipped. Three seedlings in the trials have been named; Michimac (Ms 711-8), Michigami (Ms 706—34) and Denali (AK 37-19). Seed of all entries in the tests was increased on the Lennard Farm in Emmet County where yields were good. High quality seed is available to plant all variety, yield trials on the Montcalm Experimental Farm in 1978. Research supported by a grant from the Michigan Potato Industry Commission. Variety Yield Trials 1977 Montcalm Experimental Farm Yield of Marketable Tubers in Cwt/Acre Harvested Variety Harvested Aug. 9 Cwt/A Harvested Aug. 9 Specific Gravity Harvested Aug. 9 Chip Color Harvested Sept. 1 Cwt/A Harvested Sept. 1 Specific Gravity Harvested Sept. 1 Chip Color Harvested Sept. 27 Cwt/A Harvested Sept. 27 Specific Gravity Harvested Sept. 27 Chip Color A6789-7 Katahdin Ms 711-8 Ms 706-34 AK 37-19 Rus. Burbank Monona Atlantic Jewel Onaway Oneida Superior Norchip Ms 003-69 Cent Russet Wischip 190 145 151 146 237 150 181 250 174 195 167 135 130 135 150 118 1.066 1.057 1.060 1.062 1.084 1.070 1.066 1.085 1.081 1.066 1.073 1.070 1.076 1.070 1.068 1.080 3 4 3 5 2 4 1 1 1 4 3 2 1 1 5 1 384 410 363 412 304 239 278 318 250 215 226 157 164 173 198 147 1.072 1.070 1.069 1.066 1.087 1.074 1.077 1.088 1.086 1.065 1.077 1.070 1.076 1.086 1.070 1.072 2 3 3 5 2 2 2 1 1 5 2 1 1 1 3 1 448 424 392 370 292 275 267 264 250 229 173 165 158 150 134 115 1.068 1.071 1.069 1.070 1.081 1.072 1.066 1.084 1.082 1.068 1.071 1.067 1.074 1.079 1.064 1.068 6 3 4 5 3 4 1 2 1 6 2 4 2 1 3 1 Potential Chipping Seedlings 1977 Montcalm Experimental Farm Progeny No. Flesh Color Yield Cwt/A Maturity Specific Gravity Chip color 9/12 Chip color 10/11 305-19 004-408 004-377 002-302 203-2 402-1 401-1 004-198 004-439 002-171 404-2 402-5 403-2 003-69 407-1 404-1 402-6 402-4 Yellow Yellow Yellow Yellow Yellow Cream White Yellow White Yellow Cream Yellow Witte Yellow White White White White 640 398 296 257 242 242 211 203 203 195 195 187 179 164 140 117 109 94 V. Late Medium Medium Medium V. Early Early Early V. Early Medium V. Early Early V. Early V. Early V. Early V. Early V. Early V. Early V. Early 1.075 1.078 1.077 1.075 1.073 1.062 1.074 1.075 1.081 1.075 1.074 1.071 1.075 1.079 1.063 1.072 1.068 1.076 2 1 2 2 1 1 2 1 1 1 1 1 1 1 1 1. 2 2 3 2 2 3 1 2 2 1 3 2 3 2 3 1 2 1 3 2 Potential Table Stock Seedlings 1977 Montcalm Experimental Farm Flesh Color White White White White White White Yellow White White Yellow Yield Cwt/A Maturity Specific Gravity 484 406 382 320 304 304 265 187 164 133 Medium Medium Early Medium Late Medium Early Early Early V. Early 1.069 1.085 1.084 1.071 1.078 1.071 1.059 1.066 1.080 1.071 Progeny No. 305-22 308-4 004-169 108-5 002-152 004-506 305-15 231-1 402-3 202-2 INFLUENCE OF EXPERIMENTAL NEMATICIDES ON CONTROL OF ROOT-LESION NEMATODES AND POTATO YIELDS G.W. Bird Department of Entomology Eleven formulations of nematicides were evaluated for control of root-lesion nematodes (Pratylenchus penetrans) associated with the growth and development of potatoes (cv Superior) at the Michigan State University Montcalm Potato Research Farm. Each treatment was replicated four times in a randomized block design, with each plot consisting of four rows, 34 inches apart and 50 ft in length. The fumigant nematicides were injected into the soil to a depth of 6 to 8 inches on April 21, 1977. Soil sample were taken for nematode analysis immediately before application of the soil fumigants. The non-fumigant nematicides and DiSyston 15G insecticide were applied at planting on May 13, 1977. Soil and root samples for nematode analysis (centrifugation-flotation and shaker techniques, respectively) were taken at mid-season (July 13, 1977) and at harvest (August 25, 1977). The center two rows of each plot were harvested and analyzed for quality. During the growing season the plants were maintained under normal commercial fertility, irrigation, insect control and disease control practices. There were no significant differences in the initial soil nematode population densities among the experimental plots, and in all cases the population densities were above the economic threshold levels for cv Superior grown in mineral soil under Michigan conditions (see Table) . All of the pesticide treatments resulted in good nematode control. The best control, however, was obtained with Temik 15G at 3.0 lb a.i./acre. For the second year in a row, this treatment provided season-long nematode control. This conclusion is based on several additional tests conducted in 1976 and 1977. Nemacur 15G may have provided a similar response in this test. Unfortunately, it was learned in another field test in 1977 that the insecticide standard (DiSyston 15G 3.0 lb a.i./acre) is providing about 20% control of P. penetrans. Wile this is not good enough for commercial nematode it has a significant detrimental influence on the experimental results. The only treatment that resulted in a significant increase in potato yields was Vorlex at 10 gal/acre. This result is very different than that obtained in 1974, 1975 and 1976. A possible explanation for this may be that the soil was extremely dry and warm at planting. This could have prevented optimum movement of the carbamate and phosphate nematicides in the soil and lessened the amount of early-season nematode control. This is by far the most important time for maximum control of root-lesion nematodes associated with cv Superior potatoes. The higher rate of Dacamox appeared to have greater nematicidal activity than the lower rate. Influence of eleven nematicides on the control of Pratylenchus penetrans associated with cv Superior potatoes grown in mineral soil in Michigan in 1977. Treatment and rate per acre (a.i.) P. penetrans per 100cm3 soil 4/21/77 P. penetrans per 100cm3 soil 7/13/77 P. penetrans per 100cm3 soil 8/25/77 P. penetrans per g root P. penetrans per g root 8/25/77 7/13/77 Yield (ctw/A) Check (nontreated) + DiSyston 15G 3 lb/A Vorlex 10 gal/A + DiSyston 15G 3 lb/A NAO55 10 gal/A + DiSyston 15G 3 lb/A Mocap 10G 2 lb/A + DiSyston 15G 3 lb/A Temik 15G 3 lb/A Dasanit 15G 5 lb/A + DiSyston 15G 3 lb/A Furadan 10G 3 lb/A Nemacur 15G 3 lb/A Nemacur 4SC 3 lb/A Vydate 10G 2 lb/A Dacamox 10G 3 lb/A 26a1 28a 30a 41a 33a 48a 18a 19a 15a 14a 23a 25a 3b lb 16ab 12ab 14ab 7ab 13ab 18ab /ab 2b 99a l1b 17b 17b 11b 4b 28b 6b 22b 52b 19b 46a 4b 20ab 7b 0b 4b 4b lb 2b 0b 90a 60ab 64a 12b 4b 22ab 8b 4b 6b 34ab 18ab 27ab 225a 310b 248ab 273ab 262ab 233ab 239ab 220a 270ab 229ab 282ab Dacamox 10G 5 lb/A 1The column means followed by the same letter are not significantly different (P=0.05) according to the 28a lb 251ab 8b 6b 12b SOIL INSECT RESEARCH — 1977 Arthur L. Wells and Mark Otto Department of Entomology Wireworms and white grubs often cause extensive feeding damage to the underground portion of potato plants especially to the tubers. This damage usually results in the lowering of grade or to the rejection of the crop by a buyer. These insects are usually most severe when new land which has been in a grass crop is brought into potato production. If the normal food such as grass roots is destroyed before the insects complete their development they will continue to feed on the roots of any growing crop such as potatoes. Current control programs for wireworms include broadcast applications of an organophosphate insecticide incorporated prior to planting. The only material currently labeled for white grub control is chlordane which is a chlorinated hydrocarbon. The residue problems associated with chlordane in the potato waste from processing plants can restrict its use when the wastes are fed to livestock. The current status of the chlordane registration make it imperative that alternate control programs be studied. Methods A plot to evaluate thirty different treatments including experimental materials as well as registered insecticide was established at the Norman Crook fam in Montcalm County. The plot was established in a fallow field which had been selected for its location and anticipation of an infesta­ tion of soil insects. The treatments were applied in six replications of 25 foot plots in a randomized design. The outside and every third row was left untreated so each treated row could be compared with an adjacent untreated row. This plot lay-out was done to assure adequate statistical analysis of the data since the soil insect population is often not evenly distributed over an area. Five foot alleys were left untreated between the replications. The broadcast applications were applied in water at 50 gal. per acre or as granules to the soil surface and incorporated to approximately 6 in. with a rototiller. The wide band treatments were applied as granules to a one foot wide strip (above the seed row) on the soil surface and lightly incorporated with a rake until incorporated by the opening shoes of the planter. The preplant soil treatments were applied on May 16 and the plots were planted with Superior seed with a 16 row planter on May 17. The covering discs were removed from the planter so the soil systemics Temik (aldicarb) or Furadan (carbofuran) could be applied in a band in the seed furrow of certain plots. All of the plots were then covered in another operation. The plots were fertilized, and maintained by the grower similar to the rest of the field. The plots were killed with vine killer in mid September and four hills selected at random from each plot for soil insect evaluation. The soil around the tubers was sifted to determine the numbers of wireworms, white grubs and cutworms associated with the tubers. The tubers were then placed in sacks, counted, weighed and taken to the laboratory for damage evaluation. The sampling operation for the 1200 hills took approximately 3 weeks to complete. The plot harvester from the Montcalm Experimental Farm was then used to harvest the plots and yield and tuber size from the treated plots were determined. A sample for specific gravity analysis of the tubers was saved at this time. The hill samples were washed at our Collins Rd. research laboratory and the tubers were counted and rated for wireworm damage on a scale depending on number and severity of feeding scars: Class 1 — No feeding scars Class 2 — One to two minor feeding scars Class 3 — Two to three scars in one area Class 4 — Three to five scars in separated areas Class 5 — Extensive feeding damage (A photograph to portray these damage classes is available.) The damage ratings of the individual tubers were combined to give a mean tuber rating per hill. The hill ratings for the four sample hills in each replication were compared statistically to the adjacent untreated hills. The numbers of wireworms associated with each of the hills were analyzed similarly. Since there were very few white grubs or their damage present they were not analyzed. The list of treatments, placement, wireworms per hill, mean tuber rating and percent of tubers in each damage class are presented in Table 1. Results It is unfortunate that the white grub populations were too low to evaluate since efficacy data for their control is greatly needed. The data from the wireworm numbers and damage, however, were very helpful in evaluating the efficacy of the different treatments. The numbers per hill although rather low, were evenly distributed over the plots since no significant differences were present between the untreated plots and can be assumed to have been present similarly in the treated plots. A summary of the data from the untreated plots are summarized below: Wireworms per hill Percent tubers damaged Damage rating per tuber Percent of tubers in: Class 1 Class 2 Class 3 Class 4 Class 5 3.0 65% 2.2 35% 26% 20% 13% 6% These results indicate that the low numbers (3.0 per hill) caused damage to 65% of the tubers with a large percentage of these being unmarketable (Classes 3-5). Control programs would therefore be warrented for these populations to make the tubers marketable for most uses. Several of the treatments especially those including the systemic insecticides signifi­ cantly reduced the wireworm populations and/or the damage ratings. The damage ratings are best exemplified in the class distributions. The broadcast treatments especially the liquid applications are most usable in a production program using incorporated herbicides to avoid an additional planting step. These could be followed by systemic treatments at the time of planting. The wide band placement could be used at the time of planting but would require additional granular applicators if the systemics were being applied at the same time. The physical properties of most of the treatments would require more incorporation than is provided on a planter of this type. It is possible that an attachment could be developed for this use. The systemic treatments alone also showed activity against this wireworm population, however their efficacy on higher popula­ tions may be limited. There were no significant differences between the plot yields that could be attributed to the treatments. There were also no differences between the specific gravities of the tubers in any of the plots. Residue samples from certain treatments (chlordane and Mocap) were submitted to analytical laboratories for residue analysis to provide data for future registrations. Table 1. List of Treatments and Wireworm Damage Data from the Research Plot Yield Treatment and lb ai/A (cwt/A) Percent tubers in Class 1 Percent tubers in Class 4& 5 Percent tubers in Class 2 Percent tubers in Class 3 Place * -ment Mean Mean tuber wire-worms ** rating /hill Furadan 10 G 3 lb Furadan 10 G 3 lb Untreated Temik 15 G 3 lb Temik 15 G 3 lb Untreated Chlordane 8 E 4 lb 8 E 4 lb Untreated Chlordane Chlordane 8 E 4 lb + Furadan 10 G 3 lb Untreated Chlordane 8 E 4 lb + Furadan 10 G 3 lb Chlordane 8 E 4 lb + Temik 15 G 3 lb Chlordane 15 G 3 lb Untreated 8 E 4 lb + Temik Chlordane 33 G 2 lb Chlordane 33 G 2 lb Untreated Chlordane 33 G 2 lb + Temik 15 G 3 lb Chlordane 33 G 2 lb + Temik 15 G 3 lb Untreated Dyfonate 4 E 4 lb Dyfonate 4 E 4 lb Untreated Dyfonate 4 E 4 lb + Furadan 10 G 3 lb Dyfonate 4 E 4 lb + Furadan 10 G 3 lb Untreated Dyfonate 4 E 4 lb + Temik 15 G 3 lb Dyfonate 4 E 4 lb + Temik 15 G 3 lb Untreated Dyfonate 10 G 2 lb + Temik 15 G 3 lb Dyfonate 10 G 2 lb + Temik 15 G 3 lb Untreated Dasanit 15 G 5 lb Dasanit 15 G 5 lb Untreated Dasanit 15 G 5 lb + Furadan 10 G 3 lb Dasanit 15 G 5 lb + Furadan 10 G 3 lb Untreated 2.41 0.58a 2.30 1.40b 3.92 l.46 1.72 2.67 1.04c 2.44 Wd Bnd 1.71c 2.11a 2.59 1.43a -- Wd Bnd Band -- Brdcst 1.33c 1.84c -- 2.33a 1.14b Brdcst Band -- Brdcst Band -- Wd Bnd Band -- 2.32 1.49c 2.13 1.58a 2.75 1.29b 2.54 0.21b 2.31 Brdcst 1.08a 1.62c 2.41 1.14b 2.42 0.42a 2.17 0.71a 2.92 -- Brdcst Band -- Dasanit 8 SC 5 lb Dasanit 8 SC 5 lb Untreated Brdcst 1.79 -- 2.58 3.88 2.31 1.80 2.29 Band -- Band -- l.04a 1.53c 2.92 2.23 1.88c 1.85a 3.04 2.37 Brdcst 0.83c 1.64a 2.24 1.13b 2.75 0.63a -- Brdcst Band -- Brdcst Band -- 64 34 54 38 61 36 88 37 71 30 44 28 73 53 52 37 91 29 65 40 60 34 61 32 88 32 63 33 10 22 12 25 10 18 21 24 19 20 12 l4 20 27 22 29 25 18 21 25 2 8 9 18 24 26 20 26 17 7 29 26 27 27 9 25 0 7 27 16 25 10 27 25 26 21 8 19 4 15 9 19 8 21 18 20 17 26 6 8 16 17 17 1 3 3 0 3 5 18 6 23 9 2 1 32 18 25 16 12 26 20 7 16 536 empty table cell 605 empty table cell 548 empty table cell 496 empty table cell 528 empty table cell 499 empty table cell 563 empty table cell 556 empty table cell 585 empty table cell 586 empty table cell 587 empty table cell 538 empty table cell empty table cell empty table cell 583 empty table cell Treatment and lb ai/A Place­ ment Wire- worms /hill Mean tuber rating Percent tubers in Class 1 Percent tubers in Class 2 Percent tubers in Class 3 Percent tubers in Class 4 & 5 Yield (cwt/A) Dasanit 8 SC 5 lb + Furadan 10 G 3 lb Dasanit 8 SC 5 lb + Furadan 10 G 3 lb Untreated Dasanit 15 G 2 lb Dasanit 15 G 2 lb Untreated Dasanit 15 G 2 lb + Furadan 10 G 3 lb Dasanit 15 G 2 lb + Furadan 10 G 3 lb Untreated Brdcst Band -- 0.29b 1.18b 2.19 1.79 Wd Bnd 2.04 -- 2.67 Wd Bnd Band -- 1.08b 1.33b 2.66 4.04 2.37 2.31 Dasanit 10 - Disyaton 6 lb (4 + 2 lb) Dasanit 10 - Disyaton6 lb (4 + 2 lb) Untreated 5 G Band -- 0.67b l.43b 2.48 3.67 Bendiooarb 76 WP 4 lb Brdcst 1.17a 1.78c 2.14b Bendiooarb 76 WP 4 lb Untreated 2.38 -- Bendiocarb 76 WP 4 lb + Temik 15 G 3 lb Bendiocarb 76 WP 4 lb + Temik 15 G 3 lb Untreated Isozophos 4 E 4 lb Isozophos 4 E 4 lb Untreated Isozophos 4 E 4 lb + Temik 15 G 3 lb Isozophos 4 E 4 lb + Temik 15 G 3 lb Untreated Isozophos 20 G 2 lb + Temik 15 G 3 lb Isozophos 20 G 2 lb + Temik 15 G 3 lb Untreated Counter 15 G 2 lb + Temik 15 G 3 lb Counter 15 G 2 lb + Temik 15 G 3 lb Untreated Ethoprop 10 G 3 lb Ethoprop 10 G 3 lb Untreated Ethoprop 10 G 3 lb + Temik 15 G 3 lb Ethoprop 10 G 3 lb + Temik 15 G 3 lb Untreated Pydrin 2.4 EC 0.5 lb Pydrin 2.4 EC 0.5 lb Untreated Pydrin 2.4 EC 0.5 lb + Temik 15 G 3 lb Pydrin 2.4 EC 0.5 lb + Temik 15 G 3 lb Untreated Brdcst Band -- 0.50b 1.43a 2.23 3.46 Brdcst 0.83a 1.28b -- 2.48 3.58 Brdcst Band -- Wd Bnd Band -- Wd Bnd Band -- 0.13b 1.18b 2.88 2.42 0.33b 1.24a 1.83 2.04 l.04a 1.47b 2.38 3.33 Brdcst 0.29a 1.26a -- 2.39 2.88 Brdcst Band -- 0.08a 1.25b 2.33 2.15 Brdcst 3.50c 2.48c -- 2.29 Brdcst Band -- 2.71c 1.62b 2.20 3.17 3.08 88 41 38 35 80 24 71 27 57 40 74 39 80 29 88 40 83 45 71 31 85 29 81 43 32 39 63 45 10 26 21 29 10 30 18 27 21 28 17 28 14 29 8 22 11 24 19 24 10 27 l4 28 27 21 22 22 1 16 20 20 7 19 7 26 14 19 4 18 4 22 3 18 3 17 7 18 4 24 4 15 20 20 8 18 1 17 21 16 3 27 4 20 8 13 5 15 2 20 1 20 3 14 3 27 1 20 1 14 21 20 6 15 537 empty table cell 528 empty table cell 545 empty table cell 538 empty table cell 576 empty table cell 623 empty table cell 518 empty table cell 507 empty table cell 521 empty table cell 555 empty table cell 517 empty table cell 604 empty table cell 566 empty table cell 556 empty table cell Treatment and lb ai/A Oftanol 15 G 2 lb + Temik 15 G 3 lb 15 G 3 lb Untreated Oftanol 15 G 2 lb + Temik Place­ ment Wd Bnd Band -- Chlorpyrifos 15 G 2 lb + Temik 15 G 3 lb 15 G 3 lb Untreated Chlorpyrifos 15 G 2 lb + Temik Untreated Untreated Untreated Untreated Mean wire- worms /hill Mean tuber __rating Percent tuber in Class 2 Percent tuber in Class 1 Percent tuber in Class 3 Percent tuber in Class 4 & 5 Yield (cwt/A) 0.46b 1.36b 3.8b 2.52 1.17c 1.77a 2.96 2.35 3.88c 2.70c 3.96 2.20 5.08b 2.84a 2.06 2.29 74 23 54 30 24 41 21 44 17 30 22 31 27 25 26 24 7 23 16 21 23 16 22 18 2 24 8 18 26 18 31 14 599 empty table cell 595 empty table cell 499 empty table cell 522 empty table cell Wd Bnd Band -- -- -- -- -- *Placement: Broadcast = Broadcast and incorporated; Wide Band = Applied on surface in 12" band and incorporated by planter; Band = In-row with seed. Rates based on 32 in-rows (15,390 row-ft/A); Liquids applied in water at a rate of 50 gal/A. **Statistical analysis a = Significant from adjacent untreated plot at .01 level. b = Significant from adjacent untreated plot at .05 level. c = Not significant from adjacent untreated plot at .05 level. (for damage classification refer to text). POPULATION GROWTH AND SEASONAL DEVELOPMENT OF COLORADO POTATO BEETLE Cynthia K. Blakeslee Department of Entomology The primary objectives of this investigation were: 1) to assess the potential growth of a Colorado potato beetle population under Michigan field conditions, 2) to determine, according to degree days, the time at which each developmental stage peaks, 3) to ascertain what effects the Colorado potato beetle has on yield when fields are left untreated with insectidides. A 50 by 200 ft. plot was planted with Sebagos on May 12. Sampling commenced when the first beetles were sighted on June 4; it continued twice a week thereafter. Each sample site consisted of one hill (three stalks per hill). One hundred random samples were taken each sampling date and the numbers in each stage (egg, early larvae, late larvae, and adults) were recorded. By August 12, the plot was completely defoliated and sampling was terminated. The potatoes were harvested and weighed on August 26. The seasonal development and average population of the beetle are recorded in Figure 1. This plot yielded 51.5 CWT per acre which is significantly less then the average Sebago yield of 242 CWT per acre. Other than the beetles, factors that contributed to this reduced yield were the presence of other pests and a very dry hot summer. These data form a foundation for continuing investigations of the beetle, its effect on yield and its control. Fig. 1 POTATO SEEP TREATMENT TRIALS H. Spencer Potter Department o£ Botany and Plant Pathology Procedure Four chemicals alone or in combination were compared as potato seed treatment. Seed of the variety Monona was cut and treated before planting on May 10, 1977. Treatments were replicated four times and applied either by dipping the tubers for two minutes or lightly dusting the surface. Replicates of 65 treated seed pieces were planted in single row plots fifty feet long arranged in a randomized block. Row width was 34 inches with seed pieces 9 inches apart within rows. Dysiston was used at time of planting. Additional insecticides were applied as needed in combination with fungicide sprays. Plots were irri­ gated periodically to maintain adequate soil moisture conditions. Table 1. Percent Stand and Yields of Monona Potatoes with Different Chemical Seed Treatments Treatment % Stand Yield cwt/A Yield cwt/A B Grade U.S.#1 Clorox (5.25% sodium hypochlorite) 1:18 w/water Clorox (5.25% sodium hypochlorite 1:9 w/water CGA 14703 (Ciba Geigy) 25WP 50 ppm CGA 14703 25 WP 100 ppm CGA 14703 25 WP 200 ppm Topsin M 2.5% dust Topsin M + Dithane M-45 1% + 5% dust Water No treatment 86.4 b 320.4 b 7.4a 87.3 b 333.7 b 6.3a 88.8 b 90.3ab 92.9a 93.1a 85.4 b 328.9 b 336.2ab 338.5a 353.7a 337.0a 7.0a 6.5a 7.0a 6.1a 6.3a 74.6 d 290.0 c 4.8a 80.0 c 302.9 c 7.4a Results: The data summarized in Table 1 indicates that all chemical treatments had some beneficial effect on stand and that dipping cut seed in water before planting tended to increase seed piece rot. Topsin M 2 1/2% dust treatment and CGA 14703 as a 200 ppm dip resulted in somewhat better stands than the other chemical treatments. This was reflected in the yields which tended to be higher, particularly in the case of Topsin M. None of the chemical treatments delayed germination nor were there any other indications of phytotoxicity. DRY BEAN NEMATICIDE TRIALS G. W. Bird Department off Entomology NAVY BEANS Five nematicides were evaluated for control of root-lesion nematodes (Pratylenchus penetrans) associated with dry bean (Sanilac) production. Each treatment was replicated five times in a randomized block design. Each plot contained four rows 50 feet in length and 34 inches apart. All materials were applied in an eight­ inch band at planting on June 7, 1977. Nematode population density and yield were determined from the center two rows or each plot. Excellent nematode control was obtained (Table 1) with all of the except OAC 2968. This material was also phytotoxin and not suitable for use in dry bean production. No significant (P=0.05) yield increases resulted from any of the nem­ aticide applications (Table 1). The root-lesion nematode population densities at planting were approximately 50% lower than in early May. While the economic thres­ hold for root-lesion nematodes associated with dry beans is not known, it appears to be higher than that for potatoes produced in mineral soils. This might result from the additional nematode morality caused by the later planting date for dry beans. The best nematode control and highest yields in this experiment resulted from the application of Temik 15G at 2.0 lb. a.e. per acre. KIDNEY BEANS Three nematicides were evaluated for control of root-lesion nematodes (Pratylenchus penetrans) associated with kidney bean production (Montcalm). The experimental design and methods were the same as described for the navy bean experiment. All of the materials resulted in good nematode control and were suitable for use in kidney bean production (Table 2). None of the pesticide treatments resulted in significant (P=0.05) increases in kidney bean yields. As in the navy bean experi­ ment, the population densities of root-lesion nematodes were 50% lower at bean planting time than earlier in the spring. This phenomenon should result in fewer root-lesion nematode problems in dry bean production than if the crop was planted earlier. Our observations seem to indicate that navy beans are usually planted in soils less likely to have a serious root-lesion nematode problem than are kidney beans. This might indicate that the economic threshold for root-lesion nematodes associated with kidney beans is greater than that for navy beans. Table 1. Influence of five nematicides on the control of root-lesion nematodes (Pratylenchus penetrans) associated with navy beans grown at the M.S.U. Montcalm Research Farm (cv Sanilac). Treatment and rate per acre a.i. Yield (ctw/A) P. penetrans/100cm3 soil 6/7/77 P. penetrans/100cm3 soil 7/21/77 P. penetrans/100cm3 soil 8/25/77 P. penetrans/g root 7/21/77 P. penetrans/g root 8/25/77 Check Mocap 10G (2 lb/A) Furadan 10G (2 lb/A) Vydate 10G (3 lb/A) Temik 15G (2 lb/A) OAC 30G (50 lb/A) 12.2a 11.2a 10.0a 12.3a 12.9a 4.4b 26a 17a 8a 9a 24a 16a 69b 38ab 26a 38ab 12a 44ab 40b 6a 8a la 3a 7a 903a 56b 270ab 45b 450ab 1056a 119c 38bc 25b 29bc 4a 97bc 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test. Table 2. Influence of three nematicides on the control of root-lesion nematodes (Pratylenchus penetrans) associated with kidney beans grown at the M.S.U. Treatment and rate per acre a.i. Yield (ctw/A) P. penetrans/ 100 cm 7/21/77 6/7/77 P. penetrans/ 100 cm3 soil 3 soil Montcalm Research Farm. P. penetrans/ 100 cm3 soil 8/25/77 P. penetrans/g root 7/21/77 P. penetrans/g root 8/25/77 Check Furadan 10G (2 lb/A) Temik 15G (2 lb/A) Nemacur 15G (4 lb/A) 14.8a1 13.9a 14.5a 15.6a 20a 15a 21a 20a 14a 13a 9a 5a 34a l1b 5b 5b 23a 3a 5a la 90a 5b 16b 5b 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test. CORN PLANT POPULATION AND IRRIGATION E. C. Rossman and Bary Darling Department of Crop and Soil Sciences Performance data for 74 corn hybrids evaluated in 1977 with irrigation and without irrigation are presented in Table 1. Thirteen inches of supplemental water were applied in 9 applications on June 17 and 24, July 6, 14, 23, 28 and August 9, 16, 26. Bouyoucous soil moisture blocks were placed at 6, 12, 18 and 24 - inch depths in both irrigated and unirrigated plot areas. Irrigated yields averaged 51.8 bushels more than unirrigated — 124.7 vs 72.9, an increase of 71%. Hybrids ranged from 89.4 to 158.1 irrigated and 55.5 to 88.2 bushels per acre without irrigation. Hybrids significantly better than the average yield (arranged in order of increasing moisture content at harvest) are listed below. Sixteen of the 21 hybrids were in the highest yielding group for both irrigated and unirrigated plots. Irrigated Not Irrigated Pioneer 3901 (2X) Michigan 4122 (2X) Super Crost 2350 (2X) Michigan 407-2X (2X) Pioneer 3780 (2X) Voris 2372 (2X) Asgro RX 58 (2X) Pickseed XR44 (2X) Funk G-4408 (2X) Pioneer 3591 (Sp.) Migro M-2018X (2X) Northrup King PX48 (2X) Pioneer 3535 (2X) Acco UC 3002 (2X) ADI 197 (2X) Michigan Exp. 73-2014 (2X) Migro M-0301 (2X) Acco UC 3301 (2X) Northrup King PX 46 (2X) ADI 315 (2X) Pioneer 3901 (2X) Michigan 409-2X (2X) Pioneer 3780 (2X) Voris 2372 (2X) Asgro RX 58 (2X) Pickseed XR 44 (2X) Funk G-4408 (2X) Pioneer 3591 (Sp.) Migro M-2018X (2x) Northrup King PX48 (2X) Pioneer 3535 (2X) Acco UC 3002 (2X) Super Crost S27 (2X) ADI 197 (2X) Michigan Exp. 73-2014 (2X) Acco UC 3301 (2X) Northrup King PX 46 (2X) The correlation of irrigated with unirrigated yields was highly significant, .884, indicating that the hybrids tended to respond alike in both situations. Daring the 10-year period, 1968-1977, the correlations have ranged between .7 and .9 except for 1976 when it was .490. All have been highly significant. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for the 10-year period, 1968-1977, are given in Table 2. The average yielding hybrid has yielded 49 more bushels per acre when irrigated. The highest yielding hybrids have responded with 63 bushels added yield while the lowest yielding hybrids have given only 32 bushels added yield when irrigated. These results demonstrate the importance of choosing high yielding hybrids to maximize returns from irrigation with little, if any, additional cost. Stalk lodging averaged 4.1% irrigated and 1.5% not irrigated, almost three times as much lodging on the irrigated plots. In most of the previous years, there has been less lodging when irrigated. Generally, stressed weaker plants on unirrigated plots have been more susceptible to lodging except in 1977. Plant Population X Irrigation Five adapted hybrids at four plant population irrigated and not irrigated were grown in each of 10 years, 1968-1977, Table 3. Over the 10-year period, a population of 23,300 has given the highest average yield (171 bushels) when irrigated while 19,200 has given the highest yield (110 bushels) without irrigation. The 23,300 population irrigated has given the highest yield in 9 of the 10 years. The 10-year average increase due to irrigation has been 73 bushels per acre at the 23,300 population. Moisture content of grain at harvest has averaged .5 - 1.0% higher for the higher plant populations. Stalk lodging has increased slightly with increased plant population. Table 1 Hybrid (Brand - Variety) Michigan 333-3X (3X) Michigan 280 (4X) Renk RK3 (2X) Northrup King PX20 (2X) Michigan 3093 (3X) Northrup King PX15 (2X) Funk G-5191 (4X) Pride 3315 (2X) Pioneer 3965 (3X) Migro M-0101 (2x) Funk G-4195 (3X) ADI 232 (2X) Blaney B302 (2X) Pride 2206 (2X) Funk G-4141 (2X) Michigan 3102 (2X) Super Crost S18 (2X) Blaney B303A (2X) Funk G-4252 (3X) Pickseed 185 (Sp.) Michigan 3953 (3X) ADI 195 (2X) Super Crost 1692 (2X) Pioneer 3901 (2X Blaney B305-WX (2X) NORTH CENTRAL MICHIGAN Montcalm County Trial - Irrigated vs. Not Irrigated One, Two, Three Year Averages - 1977, 1976, 1975 Zone 3 % Moisture 1977 Bushels per acre Bushels per acre Bushels per acre % Moisture % Moisture 2 yeras 1977 1977 3 yrs. 2 yrs. Irrig Not Irrig Irrig Bushels per acre Bushels per acre 3 years 2 years Not Irrig Irrig Bushels per acre 3 years Not Irrig % Stalk lodging 1977 Irrig % Stalk lodging % Stalk lodging 2 years 1977 Not Irrig Irrig % Stalk lodging 2 years Not Irrig % Stalk lodging % Stalk lodging 3 years 3 years Not Irrig Irrig 22 22 22 23 73 60 87 71 127 117 133 119 22 24.8 109.4 66.5 1.5 25.0 22 62.3 100.7 9.6 62.1 — — — — 3.8 25.7 — — 104.7 26.0 22 108.4 60.0 14.5 23 26.2 113.3 63.3 2.3 26.2 — — 117.4 70.3 26.5 57.6 94.7 26.8 24 — 112.8 66.9 63.5 — — — — 26.8 — — 108.5 27.0 23 82 70.0 110.5 59 77 70 88 --- — ___ 5.0 64 — — 7.5 63 — — 8.0 0.0 68 10.4 118 132 __ 116 126 23 — 124 141 130 125 23 24 23 99.9 61.4 78 27.2 27.4 — — 117.0 55.4 — — — ——— 27.7 85 27.8 — — 120.5 66.3 — — — --- 27.9 87 129.4 117.7 70.3 69.1 136 141 146 138 127 73 25 24 71 24 25 124 63 25 25 25 93 147 28.0 125.8 70.6 28.0 — — 108.7 64.0 28.0 25 — 110.3 61.7 28.5 25 106.2 62.8 28.6 23 — 110.3 60.4 28.6 — — 28.9 — — 29.0 26 25 68 29.1 — — 148.0 82.5 — —— 29.1 — — 142 — 136 128 121 — ___ —- — — 125 73 —— —— — —— — 66 68 133 83 55 — — — — 80 129.1 69.6 3.0 55.5 89.4 6.6 101.6 68.3 0.0 3.8 96.9 51.5 — — — — 3.4 127 —— — --- 2.5 0.0 3.8 9.8 6.9 3.3 1.7 9.2 4.4 10.4 0.0 2.3 4.5 2.3 1.4 — 7.5 3.2 0.7 0.0 — 5.2 5.0 3.2 0.0 1.6 — 0.8 0.8 0.0- — 5.4 0.0 3.8 — 3.4 1.6 — 0.0 0.0 — 3.6 — 2 8 —— 8 3 8 4 7 4 — 5 6 3 10 7 11 1 2 11 — 3 6 — — -- — — 5 1 8 16 10 — — 7 5 — — 12 — 5 17 — — — — — 5 — — — — 2 9 — 8 3 — 6 5 3 4 3 6 2 4 11 — 4 4 — -- —— — 7 12 8 5 4 4 5 — — — — — — — — Table 1 Continued Amcorn 4010 (2X) Pioneer 3958 (2X) Migro M-0105 (2X) Golden Harvest H-2370 (2X) 1 Michigan 4122 (2X) 29.2 -- 26 29.2 29.4 -- 29.4 26 29.4 26 Northrup King PX32 (2X) 1 Super Crost 2350 (2X) Funk G-4272 (3X) Amcorn 4100 (2X) Blaney B443 (3X) 29.6 26 26 29.7 29.8 -- -- 29.8 27 30.0 26 -- Blaney B506 (2X) 1,2 Michigan 407-2X (2X) Northrup King PX34 (2X) Blaney EX7305 (2X) 1,2 Pioneer 3780 (2x) 1,2 Voris 2372 (2X) Pride 4404 (2X) Wolverine W166 (2X) Michigan 410-2X (2X) Trojan TXS105A (2X) 30.0 30.1 27 30.4 -- -- 30.6 27 30.6 27 30.7 -- 27 30.9 31.0 27 31.0 28 31.2 -- -- 31.3 31.3 28 31.4 28 31.4 31.5 -- 31.5 29 31.6 -- Golden Harvest H-2450 (2X) 31.6 28 -- Funk G-4444 (2X) 31.6 28 Acco ÜC2301 (2X)____________ 31.6 27 Migro M-2022X (2X) Michigan 5443 (3X) 1,2 Asgro RX58 (2X) 1,2 Pickseed XR44 (2X) 1,2 Funk G-4408 Michigan 5802 (2X) 1,2 Pioneer 3591 (Sp.) -- -- 29 -- -- 25 -- -- 26 -- -- 27 26 -- 27 27 28 27 27 27 -- 28 -- -- 29 -- 28 26 89.2 56.5 108.0 56.1 122.4 73.8 119.8 64.8 136.9 75.3 136.6 72.3 113.0 73.8 115.9 62.8 119.4 73.7 117.7 73.5 132.3 69.1 142.5 84.0 131.2 71.3 63.6 112.8 150.8 88.2 143.4 82.2 126.3 69.1 66.1 122.3 130.5 77.4 129.7 79.0 134.1 79.1 128.8 76.8 145.2 82.1 136.7 80.1 136.8 86.5 132.7 79.0 139.1 84.8 125.2 77.8 130.2 77.1 122.1 67.3 -- 129 - - 137 158 154 138 - - 139 138 - - 160 - - 141 165 - - 148 144 150 - - - - 149 158 158 - - 155 - - 148 157 142 - - 65 - - 68 84 76 74 - - 75 75 - - 82 - - 71 85 - - 72 67 78 - - - - 77 79 85 - - 84 79 78 72 - - - - 139 - - - - 165 159 - - - - 139 144 - - 163 - - 146 165 - - 155 156 153 - - - - 155 - - - - - - 166 - - - - 160 147 - - 86 - - - - 103 96 - - - - 87 91 - - 101 - - 92 101 - - 91 91 96 - - 96 - - - - - - 106 - - - - 97 92 - - 9.6 6.1 5.8 6.2 0.7 9.3 2.7 2.1 0.0 1.4 3.7 1.5 1.5 5.3 1.6 3.5 5.8 6.4 3.8 0.8 3.0 0.0 3.1 5.4 3.5 3.4 3.9 13.5 19.1 3.2 0.0 0.8 3.7 - - 6.7 3.6 - - 3 12 3 0.0 0.0 1.5 - - 6.3 0.0 - - 5 4 7 4 2 - - 2 3 - - 2 3 6 4 5 3 3 - - 2 3 3 - - - - - - 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.0 0.7 0.0 2.3 0.0 2.3 0.0 2.8 0.0 6.6 0.7 3.8 - - - - - - - - - - - - - - - - - - 5 10 7 7 5 - - 10 10 6 6 8 4 3 5 8 8 8 9 14 11 11 - - - - - - - - - - - - - - - - - - - - 4 3 - - 3 5 - - - - 7 4 2 2 3 2 4 6 4 - - 2 - - 3 - - 4 - - 5 6 - - 8 7 4 6 7 3 5 5 - - - - - - - - - - - - - - 7 - - - - - - - - 6 - - 8 13 Table 1 Continued 1,2 Migro M-2018X (2X) 1,2 Northrup King PX48 (2X) 1,2 Pioneer 3535 (2X) Voris X380 (2X) Michigan 575-2X (2X) Amcorn 7480 (2X) 1,2 Acco UC3002 (2X) Northrup King PX529 (3X) 2 Super Crost S27 (2X) Amcorn 7300 (2X) 1,2 ADI 197 (2X) Renk RK66 (2X) Funk G-4321A (2X) 1,2 Michigan EXP73-2014 (2X) Blaney B606 (2X) 31.7 - - - - 31.7 30 31.8 31.8 - - 31.8 30 - - - - - - - - - - 32.0 32.0 - - 32.0 - - 32.1 29 32.1 27 - - - - 30 - - - - 32.2 32.2 32.3 32.4 - - 32.4 29 30 - - 29 - - 29 27 - - - - 28 31 - - - - - - 142.3 84.5 143.5 87.8 - - - 145.8 87.4 78.3 120.5 75.0 130.4 - - - 157 - - - 150 - - - 131.0 77.7 142.1 81.8 - - - 121.2 76.1 130.0 81.4 77.9 131.1 - - - 155 151 - - - 148.9 86.6 72.8 127.6 129.4 78.3 158.1 87.8 - - - 121.0 76.7 - - - 151 146 76.5 142.7 141.7 80.0 140.4 80.5 136.5 75.5 - - - 158 158 - - - - - - - - - 81 - - - 76 - - - - - - - - - 84 81 - - - - - - - - - 79 84 82 80 - - - - - - - - - - - - - - - - - - - - - 171 156 - - - - - - - - - 157 149 - - - 156 - - - 174 - - - - - - _- - - - - - - - - - - - - - - - - - - - - 106 - - - 95 103 95 - - - - - - - - - 104 - - - - - - - - - 31 92 2.2 5.9 0.0 8.4 3.0 0.0 2.8 0.7 0.0 0.8 4.5 1.5 0.0 0.8 0.9 2.3 2.2 2.2 0.0 4.1 0.0 0.8 0.0 2.3 0.0 0.8 0.0 0.0 1.6 1.5 0.0 0.0 0.0 0.0 0.0 1.6 2.4 0.7 0.0 1.5 - - - - - - - - - - - - - - - - - - - - - - 1 3 1 1 0 1 3 2 4 - - 1 3 11 13 9 2 4 10 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 4 1 3 2 - - 2 7 4 - - - - - - - - 1 4 - - - - - - 9 11 - - - - - - - - - - - - 2 7 6 1 Migro M-0301 (2X) 1,2 Acco UC3301 (2X) 1,2 Northrup King PX46 (2X) 1 ADI 315 (2X) 33.4 31 31 33.5 33.6 - - 34.1 - - Average 30.0 26 26 124.7 72.9 142 74 148 Range Least significant difference 24.8 to 34.1 22 to 31 22 to 31 89.4 to 158.1 55.5 to 88.2 116 to 165 55 to 85 119 to 174 71 to 106 0.0 to 19.1 0 to 7.5 0 to 12 1 to 17 1 to 9 1 to 13 1.5 1.0 0.7 11.7 7.0 8 6 5 5 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 Significantly better than average yield, irrigated, 1977. 2 Significantly better than average yield, not irrigated, 1977. Table 2. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for 10 years, 1968-1977. Year No. of Hybrids Tested Average Irrigated Average Not Irrigated Highest Irrigated Highest Not Irrigated Lowest Irrigated Lowest Not Irrigated 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 74 80 75 76 72 72 56 64 63 56 AVERAGE empty table cell 125 156 154 112 114 157 163 144 146 136 141 73 72 125 103 101 137 28 103 86 96 92 158 183 207 134 138 206 211 194 185 182 180 88 93 157 122 120 179 42 128 109 123 117 89 120 106 65 78 99 91 95 97 92 93 56 49 80 58 73 91 11 70 56 65 61 Table 3. Average yield at four plant populations irrigated and not irrigated for 10 years, 1968-1977. Year 15,200 Irrigated 15,200 Not Irrigated 19,200 Irrigated 19,200 Not Irrigated 23,300 Irrigated 23,300 Not Irrigated 27,400 Irrigated 27,400 Not Irrigated 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 141 153 158 118 108 152 173 122 126 144 AVERAGE 140 74 72 136 100 97 132 37 91 91 114 95 152 174 183 130 134 187 189 144 158 169 162 81 84 164 111 116 159 35 112 109 130 110 160 181 196 135 128 191 191 158 173 193 171 70 81 151 98 106 149 20 93 96 107 98 150 161 172 120 108 161 181 151 148 178 153 69 68 146 94 102 144 11 85 86 89 90