1978 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. Special acknowledgement is made to the Michigan Potato Industry Commission and the Michigan Agricultural Experiment Station for the construction of a new 40’ x 80' pole building for the storage of equipment and supplies. The building is located south of the field site and will greatly facilitate the storage and maintainance of the equipment. The building will have a room for holding seed potatoes and fertilizer in the spring and for holding research samples in the fall, but is not designed for long term potato storage. Provision has also been made for an office where research plot records can be maintained. Sincere appreciation is hereby acknowledged to the industry for this addition to the MSU research program. TABLE OF CONTENTS Page INTRODUCTION, WEATHER AND GENERAL MANAGEMENT............................................................ 1 Integrated Project - Influence of Selected Production Management Inputs on the Yield, Quality and Storability of Superior Potatoes Fertility Component M. L. Vitosh ............................................................................................................................4 Nematology Component G. W. Bird and J. Noling........................................................................................14 Storability Component B. F. Cargill, H. S. Potter, J. N. Cash and R. W. Chase. .......................................................28 Variety Adaptation and Evaluation N. R. Thompson, R. W. Chase, and R. B. Kitchen...................................................... 31 Weed Control in Potatoes W. F. Meggitt and R. W. Chase.........................................................................................37 Interactions between Colorado Potato Beetle Density, Timing of Defoliation, and Potato Yield E. J. Grafius and C. K. Blakeslee................................................................................ 39 Influence of Experimental Nematicides in Control of Pratylenchus penetrans and Potato Yields G. W. Bird and J. Noling......................................................................................................42 Potato Insect Control Studies A. W. Wells................................................................................................................................44 Effect of Potato Seed Piece Treatment on Stand and Yield - 1978 H. S. Potter................................................................................................................................54 Effect of Pre-Plant Soil Treatments on the Control of Potato Scab - 1978 H. S. Potter............................................................................................................................... 55 Fungigation Trials with Bravo 6F for Disease Control on Potatoes H. S. Potter................................................................................................................................56 Colored Bean Variety and Strain Test M. W. Adams, A. W. Saettler, and J. Taylor...............................................................58 Control of the Root-Lesion Nematode (Pratylenchus penetrans) Associated With Navy Bean (Phaseolus vulgaris L.) Yields - 1978 G. W. Bird and A. P. Elliott............................................................................................. 60 Control of the Root-Lesion Nematode (Pratylenchus penetrans) on Soybeans (Glycine max), 1978 G. W. Bird and A. P. Elliott............................................................................................. 62 Corn Hybrids, Plant Population and Irrigation E. C. Rossman, B. Darling and K. Dysinger...............................................................64 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 in 1967. This report marks the completion of twelve 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 1978. 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 eleven year temperature and rainfall data. April was considerably cooler than 1977 and the eleven year average. However, temperatures throughout the growing season were near normal. There was a very hot and humid period in late May which seriously hurt plantings of some growers; however most plot plantings were completed before this critical period. There were only two days in July, three in August and four in September when the daily maximum temperature exceeded 90°F. Rainfall patterns were erratic, and through July rainfall was nearly 3.5 inches less than the eleven year average. On August 19 a 3.70 inch rain was recorded which represented over 60% of the total received during August. Harvest weather during September was excellent which facilitated timely harvests. Irrigation applications of slightly less than one inch each were made fifteen times (June 5, 24, 28, July 6, 10, 13, 17, 20, 24, 28, August 2, 4, 7, 11, 14). SOIL TESTS Soil test results for the general plot area were: Pounds per Acre Pounds per Acre Pounds per Acre Ca K 227 960 P 395 Pounds per Acre Mg 230 pH 7.0 Table 1. The 11-year summary of average maximum and minimum temperatures during the growing season at the Montcalm Branch Experiment Station. April April Max Min May Max May Min June June Min Max July July Min Max1 August August Max Min September September Min Max 6-month average Max 6-month average Min Year 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 61 56 54 53 47 54 57 48 58 62 50 37 35 35 31 30 36 36 28 35 37 31 34 41 43 47 39 47 42 41 48 41 47 67 45 44 62 67 65 65 70 63 62 73 63 80 67 74 70 72 81 72 77 73 75 79 76 78 75 53 50 55 56 50 58 52 56 57 50 50 53 80 80 80 82 79 79 81 801 81 85 81 81 55 59 60 55 57 60 57 57 58 61 56 58 81 82 80 80 76 80 77 79 80 77 82 79 58 56 57 53 57 60 56 58 53 52 57 56 74 73 70 73 69 73 68 65 70 70 75 71 50 49 51 54 49 48 45 44 46 53 52 49 73 74 73 76 73 74 70 70 71 75 empty table cell 72 50 49 45 48 48 51 48 49 48 50 49 empty table cell 11-year average 55 Table 2. The 11-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Station. Year 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 11-year average April May 2.84 3.33 2.42 1.59 1.35 3.25 4.07 1.81 3.27 1.65 2.34 2.54 4.90 3.65 4.09 0.93 1.96 3.91 4.83 2.05 4.03 0.46 1.35 2.92 June 3.74 6.18 4.62 1.50 2.51 4.34 4.69 4.98 4.22 1.66 2.55 3.73 July 1.23 2.63 3.67 1.22 3.83 2.36 2.39 2.71 1.50 2.39 1.89 2.35 August September Total 1.31 1.79 6.54 2.67 7.28 3.94 6.18 11.25 1.44 2.61 5.90 4.63 3.30 0.58 7.18 4.00 2.60 1.33 1.81 3.07 1.40 8.62 2.77 3.33 17.32 18.16 28.52 11.91 19.53 19.13 23.97 25.87 15.86 17.39 16.80 19.50 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 - 200 lbs/A - 0-0-60 Banded at planting - 20-10-10 - 500 lbs/A Sidedressed at hilling - 46-0-0 - 300 lbs/A Rye and triticales covercrop plowed down. HERBICIDES Preplant incorporated EPTC (Eptem) at 3 lbs/A followed by delayed preemergence of metribuzin (Sencor) at 1/2 lb/A. DISEASE & INSECT CONTROL Systemic insecticide Temik was applied at 3 lbs/A. Foliar fungicide and insecticide sprays were as follows: July 5 July 15 July 22 July 28 August 5 August 12 August 21 August 28 Top killed prior to harvest with Dinoseb (Dow General) two quart/A Thiodan Thiodan + Bravo Monitor + Bravo Thiodan + Bravo Thiodan + Bravo Monitor + Bravo + Bravo Cygon Thiodan + Bravo plus crop oil concentrate (Herbimax) at one quart/A. INFLUENCE OF SELECTED PRODUCTION MANAGEMENT INPUTS ON NUTRITION AND YIELD OF SUPERIOR POTATOES Department Crop and Soil Sciences M. L. Vitosh This project was a study conducted as part of a larger project, to look at insects, nematodes, fertilizer, nitrogen, and storage characteristics and their interactions. Only the yield and nutritional aspect is report- ed here. Information on other aspects will be reported by Drs. G. Bird, R. Chase, and B. Cargill. There were two experiments conducted in 1978. The first was to evaluate two pesticides (Temik and Vorlex) at three nitrogen rates (75, 150, and 300 lbs N/A). In addition a control was established to be compared with Temik and Vorlex. The control as well as the entire experiment received several foliar insecticide applications to control insects. The experimental de- sign was a randomized complete block with nine treatments and five replica- tions. The data for this experiment are presented in Tables 1-5. The second experiment was also a randomized complete block design, but with 10 treatments (control, Temik, Vorlex, Furadan, and Dacamox) compared at two nitrogen rates (75 and 150 lbs/A). In both experiments 75 lbs N/A was supplied at planting and the remainder was sidedress at hilling to obtain the 150 and 300 lb rates. Vorlex was chiseled beneath the row prior to planting at a rate of 10 gallons per acre. All of the other soil applied pesticides were applied at 3 lbs active ingredient per acre with the fertilizer placed in two bands two inches to either side of the seed piece and two inches below. Both ex- periments were planted on May 22, using B size seed pieces of the Superior variety. Influence of Treatment of Yield Table 1 shows the yield and size distribution of potatoes as affected by the treatments for the first experiment. Total yield was maximized with 300 lbs of N and Temik or Vorlex. Fertilizer N beyond 75 lbs increased yields in the control plots less than 30 cwt, but where Temik and Vorlex were used, yields were increased 40 and 70 cwt by 150 and 300 lbs of N, respectively. Temik and Vorlex significantly increased the yield of large size tubers (over 3 1/4 inches diameter) at the 300 lbs N rate. A size yield was increased by Temik and Vorlex at all nitrogen levels. B size tuber yield was greater with Temik at the 75 and 150 lb N rates. In Table 5 similar results are reported for Temik and Vorlex with Vorlex generally giving the best yield. Dacamox and Furadan gave yields slightly lower than Temik or Vorlex but better than the control. The 150 lb N rate increased yields an average of 14 cwt/A. Dacamox significantly increased large size tubers and reduced yield of B size tubers. Soil Test Results Soil samples were taken to help with the interpretation of yield and ele- mental analysis of potato petioles. The data are presented in Tables 2 and 6. Only Calcium was significantly different in the first experiment. The differences were not consistent at each N rates, but higher Calcium values were generally observed where Temik and Vorlex were used. This could have some bearing on the lower Manganese (Mn) levels in petioles (Tables 3-4 and 7-8) with Temik and Vorlex in the first experiment, how- ever, there was no significant correlation between soil Ca and plant Mn when the simple correlation coeffecient was determined (r = .01). Influence of Treatments on Elemental Composition of Potato Petioles Nitrogen fertilizer had no significant effect on any of the elements studied in the first sampling of the first experiment (Table 3), however, the N, P, K, and Mn contents in the petioles were affected by the pesti- cide treatments. Temik caused slightly lower N and P contents, while Vorlex increased the same elements over the control. Potassium values were generally higher for both Temik and Vorlex, while Mn decreased greatly. Vorlex reduced the Mn content to nearly half the control. The same result was observed in last years studies. In the second sampling of the first experiment (Table 4), the N content of potato petioles was directly related to rate of N fertilizer. A slight increase in P and a decrease in Ca was observed with the 150 and 300 lb N rates. Manganese was again reduced by the two soil applied pesticides particularly Vorlex. For experiment 2 (Table 7) Mn was significantly reduced in the first sam- pling by Vorlex only. For the second sampling in this experiment (Table 8) N, Mn, and Zn were significantly increased by 150 lbs of N compared to 75. Petioles from Vorlex treated plots had the lowest Mn levels, while Furadan tended to increase the Mn level giving slightly higher values than the control. Dacamox had a small but insignificant affect on Mn. Summary This experiment has demonstrated the importance of Temik and Vorlex in getting maximum effecient use of N fertilizer and uptake of other nutri- ents. These two materials have consistently shown a reduction in the Manganese content of potato petioles. At present we are still unable to explain the cause and effect of this relationship. It would be interest- ing to note if other management practices which affect Manganese availa- bility and/or uptake also are yield related. Table 1. Effect of Nitrogen and pesticide treatments on size and yield of Superior potatoes. Treatments Treatments Nitrogen lb/A Pesticide 75 empty table cell Control Temik 75 Vorlex empty table cell Control Temik 150 150 Vorlex empty table cell Control Temik 300 300 Vorlex empty table cellLSD(.O5) Size Distribution A Size Distribution B <2" cwt/A 2-3 1/4" cwt/A Size Distribution Large >3 1/4"cwt/A Total 9.5 12.3 11.8 7.8 10.6 8.1 9.0 9.5 7.2 (2.5) 243 286 300 267 324 343 255 341 340 (26) 4.8 4.7 5.0 8.2 11.5 5.0 6.5 25.5 23.5 (12.4) 258 303 317 283 346 356 270 377 370 (30) Table 2. Soil test values observed in the experimental plots sampled July 7, 1978. Treatments Treat ments Soil Test Soil Test Pesticide PH lb/A Soil Test P K lb/A Soil Test Ca lb/A Mglb/A Soil Test Nitrogen lb/A 75 empty table cell Control Temik 75 Vorlex empty table cell Control 150 Temik 150 Vorlex empty table cell Control 300 Temik Vorlex 300 empty table cell LSD(.O5) lb/A 431 459 432 425 434 422 392 434 431 (NS) 312 309 303 343 333 334 323 335 327 (NS) 6.8 6.9 6.9 6.8 6.7 6.8 6.7 6.8 6.9 (NS) 939 1024 1088 1194 1002 1045 917 1088 1024 (NS) 245 256 256 281 251 242 242 272 265 (NS) Table 3. Effect of nitrogen and pesticide treatments on elemental composition of potato petioles sampled July 7, 1978. Treatments Treatments Elements Elements Ca Pesticide N % Elements Elements P % % Elements Mg % Elements Nitrogen lb/A 75 empty table cell Control Temik 75 Vorlex empty table cell Control Temik 150 150 Vorlex empty table cell Control Temik 300 300 Vorlex empty table cell LSD(.05) K % 8.28 8.78 8.60 8.24 8.75 8.58 8.35 8.48 8.18 (.32) .25 .22 .28 .23 .20 .28 .23 .22 .26 (.01) .67 .69 .68 .60 .66 .67 .70 .72 .65 (NS) 2.70 2.46 2.68 2.78 2.54 2.83 2.74 2.69 2.86 (.23) Mn PPM .53 .55 .56 .48 .53 .59 .55 .61 .62 (NS) 87 66 45 83 74 46 91 75 49 (24) Elements Zn PPM 28 25 33 30 25 31 34 29 29 (NS) Table 4. Effect of Nitrogen and pesticide treatments on elemental composition of potato petioles sampled August 4, 1978. Elements Elements Treatments Treatments Pesticide Nitrogen lb/A empty table cellControl 75 Temik 75 Vorlex empty table cellControl Temik 150 150 Vorlex empty table cellControl 300 Temik 300 Vorlex empty table cellLSD(.O5) Elements N % Elements P % K Ca % Elements Mn Mg % Elements Elements ZnPPM % 7.65 7.42 7.89 7.63 7.31 6.92 7.21 6.87 7.03 (NS) .10 .10 .11 .11 .11 .11 .11 .11 .12 (.01) 1.28 1.10 1.28 1.53 1.51 1.51 1.60 1.63 1.70 (.08) 1.54 1.67 1.48 1.42 1.36 1.30 1.36 1.41 1.32 (.17) 1.31 1.29 1.26 1.43 1.38 1.41 1.36 1.44 1.47 (NS) PPM 251 171 129 246 207 143 306 180 181 (92) 11 11 19 14 13 13 17 14 15 (NS) Table 5. Effect of Nitrogen and pesticide treatments on size and yield of Superior potatoes. Size Distribution Size Distribution Treatments Treatments Nitrogen lb/A Pesticide 75 empty table cell Control 75 Temik Vorlex 75 Furadan Dacamox 75 empty table cell Control 150 Temik 150 Vorlex 150 Furadan 150 Dacamox empty table cell LSD(.05) Size Distribution B <2" cwt/A A 2-3 1/4" Large >3 1/4"cwt/A Total 12.0 11.8 12.8 12.8 9.5 9.8 12.4 12.0 10.6 9.0 (2.5) cwt/A 276 330 351 301 313 295 349 357 315 315 (28) 12.6 12.0 7.2 8.7 15.4 9.6 15.2 10.9 9.3 25.7 (6.7) 301 353 371 322 337 314 377 380 335 350 (29) Table 6. Soil test values observed in the experimental plots sampled July 7, 1978. Treatment Treatmen Soil Test Soil Test 75 t Pesticide Nitrogen lb/A empty table cell Control 75 Temik Vorlex Furadan 75 75 Decamox empty table cell Control 150 Temik 150 Vorlex 150 Furadan 150 Decamox empty table cell LSD(.O5) Soil Test PH lb/A P lb/A K Soil Test Ca lb/A Soil Test Mg lb/A lb/A 349 368 326 324 363 322 326 308 337 309 (NS) 448 462 437 425 475 450 407 435 440 437 (NS) 1024 1003 1003 981 1130 1045 875 1003 832 811 (NS) 6.5 6.5 6.6 6.6 6.5 6.6 6.6 6.7 6.3 6.3 (NS) 242 238 245 226 264 245 226 240 204 206 (NS) Table 7. Effect of Nitrogen and pesticide treatments on elemental composition of potato petioles sampled, taken July 7, 1978. Treatments Treatments Nitrogen Pesticide Elements P % Elements N % K Ca % Elements Elements 75 empty table cell Control 75 Temik Vorlex 75 Furadan 75 Dacamox empty table cellControl 150 Temik Vorlex 150 Furadan 150 Dacamox empty table cell LSD(.05) 150 % .24 .22 .26 .22 .25 .22 .20 .27 .21 .23 (NS) 8.47 8.50 8.58 8.62 8.56 8.44 8.60 8.23 8.58 8.56 (NS) .57 .60 .55 .61 .56 .61 .56 .58 .52 .58 (NS) 2.69 2.65 2.55 2.73 2.72 2.79 2.69 2.87 2.70 2.65 (NS) Elements Mn Mg % Elements Element PPM 74 55 38 78 59 78 57 35 88 74 (28) s Pn PPM 28 27 27 28 28 28 25 30 30 28 (NS) .49 .52 .51 .51 .50 .52 .49 .55 .45 .50 (NS) Table 8. Effect of Nitrogen and pesticide treatments on elemental composition of potato petioles sampled August 4, 1978. Treatments Treatments Nitrogen Pesticide Elements P % N % Elements Elements Ca % Mg % Elements Elements 75 empty table cell Control 75 Temik Vorlex 75 Furadan 75 Dacamox empty table cell Control 150 Temik 150 Vorlex Furadan 150 150 Dacamox empty table cell LSD (05) K % 7.98 8.09 7.76 7.75 7.83 7.17 7.07 7.18 7.66 7.29 (NS) 1.32 .10 .10 1.19 .10 1.28 1.31 .10 .10 1.25 .10 1.51 .10 1.45 .11 1.49 .10 1.52 1.52 .11 (.14) (.09) 1.45 1.37 1.28 1.55 1.33 1.27 1.25 1.29 1.31 1.20 (.16) 1.27 1.15 1.21 1.33 1.13 1.38 1.48 1.56 1.26 1.36 (NS) Elements Zn Elements Mn PPM PPM 11 197 12 136 13 103 12 237 11 163 14 231 13 155 14 133 15 316 16 230 (90) (2) THE INFLUENCE OF SELECTED PRODUCTION MANAGEMENT INPUTS ON THE YIELD, QUALITY AND STORABILITY OF POTATOES G. W. Bird. and J. Noling Department of Entomology The objective of this study was to examine varying nitrogen levels and their interaction with selected insect and nematode control programs and to monitor growth and development and yield. Seedpieces (cv Superior) were planted on May 22-23, 1978 for all experiments at the Montcalm Potato Research Farm in Entrican, Michigan. Each plot consisted of four rows 50 ft. (15.24m) in length and 34 in. (.86m) apart, with 8 to 12 in. (20.5-30.5cm) spacings between plants. Plant growth and development was monitored at two week intervals throughout the season. This was accomplished by randomly selecting two plants from the outside rows of each plot and then returning them to the laboratory for analysis. In the laboratory, root weight, foliage weight and tuber weight and number were recorded at each sampling date. Soil and root populations of nematodes were estimated from samples taken at these times. Soil samples (centrifugation- flotation technique) for nematode analysis were taken by core sampling the two outside rows of each plot. Root samples (shaker technique) were derived from plants returned to the laboratory for plant growth analysis. At harvest, the center two rows of each plot were harvested, graded and weighed. During the season plants were maintained under normal commercial irrigation and insect and disease control practices. A complete random block- two factorial design was used to analyze the data, with each treatment replicated five times. Experiment I Seedpieces were planted in plots treated with three levels of Nitrogen (75, 150, 300 lb/acre) and two nematicides (Temik 15G 3.0 a.i./acre, Vorlex 10 gal/ acre). Temik 15G was applied in the seed piece furrow at planting and Vorlex was injected to a 6-8 in. (15-20 cm) soil depth oh May 3, 1978. All plots received a uniform application of 75 lbs/acre NPK (15-15-15) at planting. The plots to receive an added nitrogen treatment were sidedressed at an application rate of 100 lb/acre on June 13, 1978 and either 75 lb/acre and 125 lb/acre on June 22, 1978. Nitrogen application rate and nematicide treatment contributed significantly to final yield. Irregardless of the pesticide used, yields were higher with the higher nitrogen application rate (Table 1). The total yield from plots treated with nematicides were significantly higher (P = 0.05) than that of the controls. Total yield of plots with nitrogen rates above 150 lb/acre were significantly (P = 0.05) different from the controls and the 75 lb/acre nitrogen plots but were not significantly different from the 300 lb/acre plots. Highest total yields were observed in the 300 lb/acre nitrogen plots with Temik 15G and Vorlex. Yields of A grade potatoes showed similar results to that of total yield (Table 1). Temik 15G and Vorlex, with nitrogen application rates above 150 lb/acre, significantly (P = 0.05) increased the yield of A grade potatoes. Both Temik 15G and Vorlex at the 75 lb/acre nitrogen rate significantly (P = 0.05) increased the B grade potato yield (Table 1) compared to the Vorlex treatments at the 300 and 150 lb/acre nitrogen rates. Temik 15G at the 300 lb/acre nitrogen rate resulted in the highest yield of Jumbo grade potatoes (Table 1). This was significantly (P = 0.05) greater than any treatment at the 75 lb/acre nitrogen rate. There were no significant differences in soil population densities of Pratylenchus penetrans among plots until the June 8, 1978 sample (Table 2) . From June 8,1978, Temik 15G significantly reduced soil population densities of P. penetrans at all nitrogen rates. Based on P. penetrans recovered from root tissue in this test, Temik 15G resulted in the best nematode control. There were no significant (P=0.05) differences in tuber or root Growth and development season long (Table 4 and Table 5 respectively). From June 25,1978 foliage weight were higher in all nematicide treatments (Table 6). Experiment II Seedpieces were planted in plots treated with two levels of Nitrogen(75-150 lb/acre) and four nematicide treatments (Temik 15G 3.0 a.i./acre, Vorlex 10 gal/ acre, Furadan 10G 3 lb a.i./acre, Dacamox 10G 3 lb a.i./acre). All nematicides were applied in the seed piece furrow at planting, except Vorlex 10 gal/acre which was injected to a 6-8inch(15-20cm) soil depth on May 3,1978. All plots received a uniform application of 75 lb/acre NPK (15-15-15) at planting and half the plots were sidedressed with an additional 75 lb/acre NPK June 22,1978. Nitrogen application rate and nematicide treatment contributed significantly (P=0.05) to the total yield (Table 7). Both Temik 15G and Vorlex 10 gal/acre, at each nitrogen rate, significantly(P=0.05) increased total yield above the controls. With each nematicide used in this test, higher yields occurred at the greater nitro- gen rate. Yield of A grade potatoes were similar to the total yield results. Vorlex 10 gal/acre at both nitrogen rates was significantly(P=0.05) greater than the con- trols. Dacamox 10G at the higher nitrogen rate significantly(P=0.05) increased Jumbo grade yield over all other plots. There were no significant(P=0.05) differ- ences in B grade yield, although Dacamox 10G at both nitrogen rates resulted in the lowest yield. There were no significant(P=0.05) differences in soil population densities of Pratylenchus penetrans from the initial sample of May 22,1978 to the fourth of July 12, 1978(Table 8). At both nitrogen rates, Temik 15G resulted in a significant(P=0.05) decrease in soil population densities of P. penetrans from all other plots. This continued until harvest. Significant(P=0.05) differences in root population density of P. penetrans between plots were apparent season long(Table 9). Temik 15 G at the 751b/acre nitrogen rate significantly(P=0.05) decreased root population density season long over all plots. Results of root samples taken from July 12, 1978 to harvest showed that Temik 15G at both nitrogen rates resulted in the best nematode control. Furadan 10G appeared to decrease root and soil population densities of P. penetrans but was only significantly(P=0.05) different frcm a con- trol or. August 1, 1978. Statistical analysis of plant growth and development data showed few significant(P=0.05) differences in root weight throughout the season (Table 10). Furadan 10G at the higher nitrogen rate significantly(P=0.05) increased root weight during the sample of June 25,1978. This may have, by increasing root weight early, contributed to the higher soil and root population densities observed in these plots. It appears that Dacamox 10C at both nitrogen rates, delays the growth and development of the foliage and tubers(Table 11 and 12 respectively). This resulted in lower foliage and tuber weights during early season and significant- ly (P=0.05) higher plant and tuber weights during the final sample. This may be due in part to the nematicidal and/or plant growth characteristics of this material. TABLE 1 Influence of selected management inputs on the yield and grade of potatoes (cv Superior) TREATMENT 75N 2 Check 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 300N Check 300N Temik 15G 3 lb a.i./acre 300N Vorlex 10 gal/acre YIELD (CTW/ACRE) YIELD (CTW/ACRE) Jumbo Grade 4.8a 4.6a 4.9a 8.lab 11.4ab 10.8ab 6.5a 25.2b 23.2ab A YIELD (CTW/ACRE) Grade 237.6a 1 296.5bc 282.5c 263.4ab 319.7d 339.1d 251.6ab 337.5d 335.5d B Grade 9.4ab 12.1b 11.7b 7.7a 10.5ab 8.0a 8.9ab 9.4ab 7.1a YIELD (CTW/ACRE) Total 254.8a 299.3bc 311.9c 276.5abc 340.93d 356.0d 267.9ab 371.5d 365.7d 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 2 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT 75N 2 Check 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 300N Check 300N Temik 15G 3 lb a.i./acre 300N Vorlex 10 gal/acre P. penetrans per 10 cm3 soil P. penetrans per 10 cm 3 soil 5/27/78 6/08/78 P. penetrans per 10 cm3 soil 6/25/78 penetrans per 10 cm3 soil P. 7/12/78 P. penetrans per 10 cm3 soil 8/01/78 8/21/78 P. penetrans per 10 cm 3 soil 1.0a 1 0.0a 1.0a 2.0a 1.0a 2.0a 2.0a 2.0a 1.0a 1.0a 0.0a 0.0a 1.0a 0.0a 0.0a 1.0a 0.0a 0.0a 1.0a 0.0a 1.0a 0.0a 0.0a 0.0a 1.0a 0.0a 0.0a 2.0a 0.0a 2.0a 3.0a 0.0a 0.0a 2.0a 1.0a 0.0a 4.0d 0.0a l.0ab 2.0bc 0.0a l.0ab 3.0cd 0.0a l.0ab 2.0abc l.0ab 2.0ab 7.0c 0.0a l.0ab 4.0bc 0.0a 3.0abc 1Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 275N = 75 lb. nitrogen per acre TABLE 3 Influence of selected management inputs on population density of P. penetrans on potatoes(cv Superior) TREATMENT 75N 1 Check 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 300N Check 300N Temik 15G 3 lb a.i./acre 300N Vorlex 10 gal/acre P. penetrans per .1g root tissue 6/25/78 7.0c1 0.0a 1.0a 6.0bc 1.0a 2.0ab 6.0bc 2.0a 1.0a P. penetrans per .1g root tissue P. penetrans per .1g root tissue P. penetrans per .1g root tissue 7/12/78 9.0ab 8/01/78 l0.0cd 0.0a 1.0a 7.0b 0.0a 2.0a 10.0b 0.0a 1.0a 0.0a 2.0ab 16.0d 0.0a 4.0bc l0.0cd 5.0ab 4.0bc 8/21/78 3.0bc 1.0abc 3.0abc 3.0abc l.0ab 2.0abc 4.0c 0.0a 1.0abc 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 4 Influence of selected management inputs on tuber weight of potatoes(cv Superior) TREATMENT 75N 2 Check TUBER WEIGHT/PLANT(GRAMS) TUBER WEIGHT/PLANT(GRAMS) TUBER WEIGHT/ PLANT(GRAMS) 6/25/78 12.5a1 2 7/12/78 237.5a 8/01/78 758.4a TUBER WEIGHT/ PLANT(GRAMS) 8/21/78 984.3a 75N Temik 15G 3 1b a.i./acre 75N Vorlex 10 gal/acre 150N Check 150N Temik 15G 3 1b a.i./acre 150N Vorlex 10 gal/acre 300N Check 300N Temik 15G 3 1b a.i./acre 300N Vorlex 10 gal/acre 17.7a 17.0a 8.0a 14.4a 22.3a 11.0a 14.2a 26.4a 307.4a 358.7a 286.1a 236.1a 331.9a 215.8a 284.4a 364.9a 773.5a 753.0a 596.0a 837.5a 673.4a 692.8a 808.6a 762.2a 880.3a 1147.7a 1103.4a 1071.5a 963.3a 858.4a 980.0a 1132.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 5 Influence of selected management inputs on root weight of potatoes (cv Superior) ROOT WEIGHT (GRAMS) ROOT WEIGHT (GRAMS) ROOT WEIGHT (GRAMS) TREATMENT 75N 2 Check 6/25/78 ROOT WEIGHT (GRAMS) 6/08/78 4.932a1 7.771a 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 150N Check 4.306a 4.522a 4.920a 150N Temik 15G 3 lb a.i./acre 4.070a 150N Vorlex 10 gal/acre 300N Check. 300N Temik 15G 3 lb a.i./acre 300N Vorlex 10 gal/acre 3.916a 5.058a 3.530a 5.040a 7.812a 8.459a 7.440a 8.595a 9.415a 8.475a 10.552a 10.626a 7/12/78 8/01/78 9.819a 10.089a 9.059a 8.886a 8.138a 7.972a 10.380a 10.553a 7.871a 9.595a 8.040a 6.949a 8.035a 7.426a 8.356a 8.047a 7.435a 7.969a ROOT WEIGHT (GRAMS) 8/21/78 4.400a 4.773a 5.393a 5.720a 6.452a 4.580a 7.174a 5.321a 6.733a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TAELE 6 Influence of selected management inputs on foliage weight of potatoes (cv Superior) FOLIAGE WEIGHT (GRAMS) FOLIAGE WEIGHT (GRAMS) FOLIAGE WEIGHT (GRAMS) TREATMENT 75N 2 Check FOLIAGE WEIGHT (GRAMS) 6/08/78 37.13a 1 6/25/78 264.561a 7/12/78 430.30a 8/01/78 FOLIAGE WEIGHT (GRAMS) 8/21/78 511.615ab 57.088a 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 150M Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 300N Check 300N Temik 15G 3 lb a.i./acre 300N Vorlex 10 gal/acre 32.12a 30.12a 33.94a 33.86a 30.39a 34.62a 30.16a 41.59a 293.418a 624.814a 557.877ab 170.005ab 397.888ab 647.367a 600.907ab 149.042ab 259.862a 307.017ab 497.587a 588.190a 569.527ab 112.638ab 557.931ab 314.218c 392.134ab 583.923a 783.019b 156.036ab 256.022a 469.901a 446.155a 101.647ab 367.218ab 565.215a 640.830a 242.938bc 435.979b 675.947a 723.642a 246.928bc 1 Column followed by the same letter are not Significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre Table 7 Influence of selected production management inputs on the yield and grade of potatoes(cv Superior) TREATMENT 75N 2 Check 272.8a 1 75N Temik 15G 3 lb a.i./acre 325.7bcd 75N Vorlex 10 gal/acre 346.6cd 75N Furadan 10G 3 lb a.i./acre 297.3ab 75N Dacamox 10G 3 lb a.i./acre 309.1abc 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 289.9ab 344.9cd 352.4c 150N Furadan 10G 3 lb a.i./acre 307.6abc 150N Dacamox 10G 3 lb a.i./acre 311.7abc YIELD(CTW/ACRE B YIELD(CTW/ACRE )A Grade YIELD(CTW/ACRE) Jumbo Grade ) Grade 11.8a 11.7a 12.6a 12.6a 9.4a 9.4a 12.3a 11.8a 10.1a 8.9a 12.4a 11.8a 7.1a 8.6a 15.2a 8.6a 15.1a 10.8a 8.9a 25.4b ) Total YIELD(CTW/ACRE 297.1a 349.2cde 366.3de 318.5abc 333.7abcd 307.9ab 372.Ide 375.0e 326.6abc 346.0bcde 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre Table 8 Influence of selected management inputs on population density of P. penetrans on potatoes(cv Superior) TREATMENT 75N 2 Check P. penetrans per 10 cm 3 soil 5/22/78 1.0a 1 75N Temik 15G 3 1b a.i./acre 75N Vorlex 10 gal/acre 75N Furadan 10G 3 1b a.i./acre 75N Dacamox 10G 3 1b a.i./acre 150N Check 150N Temik 15G 3 1b a.i./acre 150N Vorlex 10 gal/acre 150N Furadan 10G 3 1b a.i./acre 150N Dacamox 10G 3 1b a.i./acre 0.0a 1.0a 1.0a 1.0a 2.0a 1.0a 3.0a 1.0a 1.0a P. penetrans per 10 cm3 soil 6/08/78 P. penetrans per 10 cm3 soil 6/25/78 P. penetrans per 10 cm3 soil 7/12/78 P. penetrans per 10 cm 3 soil 8/01/78 P. penetrans per 10 cm 3 soil 8/21/7 4.0a 0.0a 0.0a 0.0a 1.0a 1.0a 0.0a 0.0a 1.0a 1.0a 4.0a 0.0a 1.0a 4.0a 5.0a 6.0a 0.0a 4.0a 2.0a 1.0a 3.0a 0.0a 2.0a 1.0a 1.0a 3.0b 0.0a 3.0a 3.0a 1.0a 5.0b 0.0a 1.0b 4.0b 1.0b 6.0b 0.0a 3.0a 4.0a 2.0a 8.0b 0.0a 4.0b 8.0b 5.0b 9.0b 0.0a 4.0a 5.0a 5.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 9 Influence of selected management inputs on population density of P. penetrans on potato(cv Superior) P. penetrans per .1g root tissue P. penetrans per .1g root tissue P. penetrans per .1g root tissue TREATMENT 75N 2 Check 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 75N Furadan 10G 3 lb a.i./acre 75N Dacamox 10G 3 lb a.i./acre 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 150N Furadan 10G 3 lb a.i./acre 150N Dacamox 10G 3 lb a.i./acre P. penetrans per .1g root tissue 6/08/78 7/12/78 6/25/78 8/01/78 P. penetrans per .1g root tissue 8/21/78 44.0b 1 2.0a 20.0ab 13.0ab 20.0ab 16.0ab 3.0ab 14.0ab 23.0ab 9.0ab 4.0b 0.0a 6.0c 2.0bc l.0bc 4.0c 2.0ab 3.0bc 6.0c l.0bc l0.0bc 0.0a 8.0bc 5.0bc 7.0bc 18.0c 0.0a 6.0bc 12.0bc 3.0b 37.0c 0.0a 10.0b 23.0bc 6.0b 39.0c 0.0a 11.0b 12.0b 7.0b 6.0ab 0.0a 3.0ab 18.0ab 6.0ab 15.0b 0.0a 8.0ab 6.0ab 14.0b 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 10 Influence of selected management inputs on the root weight of potatoes(cv Superior) TREATMENT 75N 2 Check 75N Temik 15G 3 lb a.i./acre 3.939a 3.454a 75N Vorlex 10 gal/acre 75N Furadan 10G 3 lb a.i./acre 4.454a 75N Dacamox 10G 3 lb a.i./acre 3.830a 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 3.784a 3.454a 4.110a 150N Furadan 10G 3 lb a.i./acre 3.988a 150N Dacamox 10G 3 lb a.i./acre 3.004a ROOT WEIGHT (GRAMS) ROOT WEIGHT (GRAMS) 7/12/78 6/25/78 6/08/78 ROOT WEIGHT (GRAMS) 3.104a 1 ROOT WEIGHT (GRAMS) 8/01/78 11.196a 10.486a 8.308a 10.524a 10.304a 10.002a 9.262a 9.244a 10.604a 9.930a ROOT WEIGHT (GRAMS) 8/21/78 5.328a 5.156a 4.722a 5.252a 4.520a 5.292a 4.412a 4.942a 5.032a 6.830a 8.876ab 9.706ab 9.018ab 9.446ab 8.716ab 8.842ab 9.696ab 10.220ab 11.228b 6.602a 10.068a 11.768a 11.266a 10.266a 10.408a 9.460a 10.892a 12.266a 13.672a 9.866a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre Table 11 Influence of selected management inputs on the foliage weight of potatoes(cv Superior) TREATMENT 75N 2 Check FOLIAGE WEIGHT (GRAMS) 6/08/78 27.2a 1 75N Temik 15G 3 1b a.i./acre 29.6a 75N Vorlex 10 gal/acre 28.8a 75N Furadan 10G 3 lb a.i./acre 31.8a 75N Dacamox 10G 3 lb a.i./acre 27.5a 150N Check 30.2a 150N Temik 15G 3 lb a.i./acre 34.8a 150N Vorlex 10 gal/acre 30.5a 150N Furadan 10G 3 lb a.i./acre 31.7a 150N Dacamox 10G 3 lb a.i./acre 24.2a FOLIAGE WEIGHT (GRAMS) 6/25/78 FOLIAGE WEIGHT (GRAMS) 7/12/78 FOLIAGE WEIGHT (GRAMS) 8/01/78 FOLIAGE WEIGHT (GRAMS) 8/21/78 290.3ab 334.lab 388.6b 299.2ab 249.2a 286.3ab 406.2b 383.0b 357.3ab 230.8a 609.7a 744.0a 669.6a 612.9a 593.3a 592.4a 742.9a 788.7a 671.4a 602.7a 475.3a 562.3a 495.0a 501.7a 582.9a 509.7a 535.2a 587.6a 591.2a 607.9a 55.7a 88.4a 72.2a 50.5a 133.0a 90.4a 135.0a 111.2a 116.8a 211.4b 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre TABLE 12 Influence of selected management inputs on the tuber weight of potatoes (cv Superior) TUBER WEIGHT/PLANT (GRAMS) TUBER WEIGHT/PLANT (GRAMS) TREATMENT 75N 2 Check 75N Temik 15G 3 lb a.i./acre 75N Vorlex 10 gal/acre 75N Furadan 10G 3 lb a.i./acre 75N Dacamox 10G 3 lb a.i./acre 150N Check 150N Temik 15G 3 lb a.i./acre 150N Vorlex 10 gal/acre 150N Furadan 10G 3 lb a.i./acre 150N Dacamox 10G 3 lb a.i./acre 6/25/78 9.0a 1 14.9ab 29.1b 17.3ab 8.9a 16.5ab 24.8ab 20.lab 20.6ab 7.3a 7/12/78 310.7a 364.7a 370.5a 329.7a 281.8a 266.4a 385.7a 419.4a 355.1a 266.0a TUBER WEIGHT/PLANT (GRAMS) 8/01/78 757.7a 832.3a 810.6a 733.5a 726.4a 817.2a 775.0a 843.4a 847.6a 781.0a 8/21/78 TUBER WEIGHT/PLANT (GRAMS) 871.0a 923.4a 1071.2a 906.0a 822.8a 871.8a 1121.8a 1088.8a 819.4a 1113.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 75N = 75 lb. nitrogen per acre INFLUENCE OF PRESTORAGE CHEMICAL TREATMENTS ON OUT-OF-STORAGE POTATO QUALITY B. F. Cargill, Department of Agricultural Engineering H. S. Potter, Department of Botany and Plant Pathology J. N. Cash, Department of Food Science R. W. Chase, Department of Crop and Soil Science In 1977 different field production treatments were used on one Range of Superior potatoes at the Montcalm Potato Experiment Station. This potato plot was part of the MSU Integrated Potato Project. The potatoes were planted May 10 and harvested August 23, 1977. There were twelve (12) different field treatments and four (4) re- plications of each treatment; the production treatments involved different levels of nitrogen and other chemicals (details of these treatments are shown in the footnote of the following table in this report). These 1977 Superior potatoes were harvested using the MSU Potato Plot Harvester. The four replications of each treatment were combined into composite bagged samples (approximately 15 kilo each). Some potato lots were post harvest chemically treated with Mertec, Chlorine, and P 293 (a sprout inhibitor); other lots remained untreated as checks. These various lots (bags) of potatoes were stored in cubicles at MSU. They were suberized at 15.6° C and 95% RH for 10 days; and stored at 12.8° C and 95% RH. After six (6) months these potatoes were evaluated for market quality by H. S. Potter and B. F. Cargill; each tuber was examined individually. A potato was rated "good" if it was a marketable potato with no visual evidence of degradation. The results are shown in the following table. This is one year data and a similar treatment on Superior potatoes will be conducted for three consecutive years (1977, 78 & 79). The 1978 Superior potatoes are in storage and will be reported in the next years Montcalm Station Report. Publications Influence of Prestorage Chemical Treatments on Out-of-Storage Potato Quality (1978). Cargill, B.F., Potter, H.S., Cash, J.N. and Hack, D.W. Microfiche 78-4056. American Society of Agricultural Engineers, St. Joseph, Michigan 49085 Table 6. Quality evaluation of Superior potatoes (1977) produced under 12 different field production treatments1, mechanically harvested with minimal bruising (1X bruise level), stored at 12.8 °C (55 °F) and 95% RH after suberization at 15.6 °C (60 °F) for ten days and evaluated after six months storage. Production & Chemical Treatments 1X-Unwashed (No chemicals) QUALITY EVALUATION 2 (%) QUALITY EVALUATION 2 (%) 2 (%)Good QUALITY EVALUATION Fusarium Dry Rot Sprouts Sprout Rating QUALITY EVALUATION 2 (%) 1X-Unwashed (No chemicals) 1X-Unwashed (No chemicals) 1X-Unwashed (No chemicals) 1X-Unwashed (No chemicals) 1 2 3 4 5 6 7 8 9 10 11 12 Average no chem. 1X-Unwashed w/chemicals 3 1 2 3 4 5 6 7 8 9 10 11 12 Average w/chem. 98.5 95.8 93.5 89.1 89.0 87.4 89.9 84.3 87.3 100.0 88.8 91.6 91.3 1.5 4.2 6.5 10.9 11.0 12.6 10.1 15.7 12.7 0.0 11.2 8.4 8.7 1X-Unwashed w/chemicals 3 1X-Unwashed w/chemicals 3 98.2 94.0 95.1 96.2 98.0 98.5 94.6 95.6 97.1 98.9 98.0 98.2 96.9 1.8 6.0 4.9 3.8 2.0 1.5 5.4 4.6 2.9 1.1 2.0 1.8 2.1 1, 2, 3 Footnotes on next page. 100 100 100 100 100 100 100 100 100 100 100 100 100 2.0 4.0 3.5 2.5 3.5 3.0 3.5 3.5 3.5 4.0 4.0 3.5 3.4 1X-Unwashed w/chemicals 3 1X-Unwashed w/chemicals 3 100 100 100 100 100 100 100 100 100 100 100 100 100 2.0 2.5 2.0 2.0 2.0 2.5 2.0 2.5 2.0 2.5 2.0 2.5 2.2 Table 6 Cont. 1 Twelve different treatments replicated four times produced the Superior potatoes for 50 lbs. N, Check (foliar insecticides as needed) 50 lbs. N. Temik 15G (3.0 lb. a.i./A plus foliar as needed) this test to determine if production practices influenced storability of Superior potatoes. The 12 treatments applied by the Dept. of Crop & Soil Science, MSU were as follows: 1. 2. 50 lbs. N, DiSyston 15G (3.0 lb. a.i./A plus foliar insecticides as needed) 3. 4. 50 lbs. N, Vorlex (12 gal/A plus DiSyston, plus foliar as needed) 5. 6. 7. 8. 150 lbs. N. Vorlex (12 gal/A plus DiSyston plus foliar as needed) 9. 300 lbs. N, Check (foliar insecticides as needed) 10. 11. 300 lbs. N, Temik (3.0 lb. a.i./A plus foliar as needed) 12. 150 lbs. N, Check (foliar insecticides as needed) 150 lbs. DiSyston 15G (3.0 lb. a.i./A plus foliar insecticides as needed) 150 lbs. N, Temik 15G (3.0 lb. a.i./A plus foliar as needed) 300 lbs. N. DiSyston 15G (3.0 lb. a.i./A plus foliar insecticides as needed) 300 lbs. N, Vorlex (12 gal/A plus DiSyston, plus foliar as needed) These potatoes were planted May 10 at the MSU/Montcalm Potato Research Station and harvested August 23, 1977. Vorlex was applied April 18, 1977. 2 Quality evaluations are as follows: The term "good" refers to potatoes that were individually inspected and no visible infection; a potato was classified as having a sprout if the sprout could be observed above the surface; and a sprout rating from 0.0-4.0 was given. The rating approximated the average length in inches of the sprouts in the sample - any sprout over 10 cm (4"), was classified as a "4". 3 The chemicals applied were Mertect (1500 ppm) and chlorine (sodium hypochlorite) (200 ppm) and P-293 at 1% solution. The resulting solution was applied at the rate of 4.2 l/1000 kg (1 gallon per ton) of potatoes. 4In the 12 treatments, the abbreviation, a.i., refers to "active ingredients". VARIETY ADAPTATION AND EVALUATION N. R. Thompson, R. W. Chase, R. B. Kitchen Department of Crop and Soil Sciences *This research is financially supported by the Michigan Potato Industry Commission. This industry support has permitted the expansion of variety development work in Michigan. A. Dates of Harvest (Montcalm Research Farm) To determine economical yields of potatoes for early, mid season and late harvest 29 cultivars were planted, May 4, in randomized and replicated trials in three blocks for harvest on August 8, August 21 and September 30. All cultivars were planted in the block for the August 31 harvest. Those reported to be earlier were omitted from the September 20 harvest and the later developing cultivars were omitted from the block to be harvested August 8. Yields are reported as cwt/A US#1, Table 1. Specific gravity data was obtained within a few days of harvest and chip data was recorded on the August 8 and 31 harvests. More complete data will be obtained later on chips, cooking-color, texture and flavor after storage. Several cultivars appear well adapted to the Michigan environment as yields and quality were excellent. Denali, which has been in trials since 1974 as AK-37-19 produced exceptionally high yields and high solids on both August 8 and August 31. It makes good potato chips and its table quality is excellent. Atlantic, a variety from the USDA potato breeding program at Beltsville, is comparable to Denali in yield, slightly lower in total solids, but much higher than most varieties. It makes excellent potato chips. This variety has found favor in Florida and on the Eastern Seaboard. As well as a variety for Michigan there is a potential market for seed. Like all new varieties, the demand will be dependent upon its performance. Because of instances of hollow-heart and internal necrosis, smaller acreages are recommended in the initial years to determine if these defects will be a problem in specific locations. Michibonne is a release from Michigan State and tested as M.S. 709. This variety consistently has produced high yields of smooth attractive tubers for the fresh market. It has a tendency to oversize but even very large tubers are seldom hollow. It is satisfactory for chip processing at harvest but does not recondition. Michimac is a release from Michigan State and tested as M.S. 711-8. This variety produces exceptionally high yields of smooth attractive tubers with good cooking qualities for the fresh market. Hollow heart is rarely a problem in oversize tubers. Belchip, a release from the U.S.D.A. breeding program at Beltsville was introduced this year. As the name implies it is recommended for chip processing. Yields have been good with higher than average total solids. In initial trials chip quality is excellent. Chipping quality from storage will be determined this winter. BelRus is a release from the U.S.D.A. breeding program at Beltsville. This variety produced very smooth uniform russet skinned tubers. Contrary to reports from other areas, oversize was not a problem in Michigan. In fact the tuber set was high with too few tubers of 10 oz or over to interest processors. Additional testing especially in spacing trials will be necessary to evaluate the variety. Croatan is a vigorous variety from North Carolina which produced high yields in the first year of testing. Chip quality was good at harvest. The high yield assures that it will be included in trials to determine its adaptation to the Michigan environment. Several seedlings from the Michigan program offer a range of maturities for various markets. Seed of the new varieties and seedlings is limited but with the Michigan Potato Industry Commissions’ support, all were increased on the Emmet County farm of Wayne Lennard and Sons. Samples have been submitted for the Florida test. Cultivars which show the greatest potential at this time are M.S. 2-152, M.S. 4-408 and M.S. 4-169. Small lots will be available to Premier Foundation Growers under the new regulations for introduction of new varieties. B. Overstate Potato Variety Trials. Overstate potato variety trials were conducted in several locations this year: Shoemaker Brothers in Allegan; Don and Jerry Meyers in Bay; Ardie Jenkins in Kalkaska; Frank Falkeis in Delta and Beaudoin Borthers in Houghton. In addition to the replicated trials at these locations, single row plantings of several varieties were conducted at the Bill Altman Farm in Presque Isle and Ardie Jenkins in Kalkaska. Harvests were made at all locations, however, the data obtained at Allegan County has been omitted because of the damage done by the heavy rains in June. Most of the field in which the plots were located was totally lost and the damage to the plot area was apparent at harvest as yields were well below normal. Data from the Kalkaska location are not included because several plots were lost from the wheel tracks of the center pivot irrigation system. Table 2 summarizes the yield data from three locations. Yields at all locations were very acceptable, however, one should consider the relative yield differences between varieties particularly when compared with standard varieties such as Norchip, Superior and Russet Burbank. Varieties consistent in yield at all locations were Atlantic, Denali, Michibonne, Michimac and MS 4-169, all being above the average. Varieties consistent in producing high specific gravity were Atlantic, Denali, MS 3-69 and MS 4-169. Atlantic has continued to yield exceptionally well, however, the incidence of hollow heart and/or internal browning has been reported more frequently this year. We will need to continue to monitor this concern in hopes of identifying the cultural conditions which appear to influence this problem. The variety does have exceptionally good yield and dry matter potential and growers wishing to observe it in their program should perhaps do it on a modest basis at first. Buckskin was evaluated for the first time in 1978. Its performance was eratic with poor stands resulting in the two Upper Peninsula locations. It had a high percentage of tubers over 3 1/4 inch. BelRus did not yield as well as anticipated. The tubers are smooth, quite blocky in shape and have a very dark russet. We shall continue to evaluate this variety. The Butte, a recent long russet variety released from Idaho, performed well at the two Upper Peninsula locations. In previous tests at the Montcalm Research Farm its yields has been comparable to Russet Burbank with a higher percentage of U.S. number l’s Centenial Russet in previous trials has not yielded well although it had good general appearance. It has low dry matter and its place in the Michigan industry is questionable. The MS 4-169 and MS 4-198 cultivars performed exceptionally well and will be evaluated intensively in 1979. Michibonne and Michimac also performed exceptionally well and are worthy of trial lots by tablestock producers. C. Variety Adaptability. A second phase of the over state variety evaluations was the long-row plantings of several varieties in Kalkaska and Presque Isle Counties. Again, the Kalkaska data are omitted because of the plot damage by the irrigation system. The objectives of this project were to evaluate selected varieties under actual grower conditions. One hundred pound lots of each of eight varieties were machine cut and machine planted at the Altman Farm in Presque Isle County on May 22. Several follow up visits were made to observe stands and growth characteristics. Harvests were made oh September 26 with the research plot harvester. Four yield checks were taken on each variety and these data are summarized in Table 3. In terms of yield it should be noted that Superior, Oneida and Atlantic were all affected by sprayer wheel tracks during the growing season and this undoubtedly reduced the yield potential of these varieties. The stand of Michigami was poor, an observation made at several other locations. This variety will be withdrawn from release. The Ontario produced the greatest yield, however, a high percentage of tubers were poorly shaped because of second growth and heat sprout. The tubers did not size well as indicated by the percent over 3 1/4”. In contrast, the Michibonne, Michimac and Snowchip had a high percentage of large tubers, particularly Michibonne. Closer spacings of 7-9 inches would be desirable for these varieties and would likely add significantly to their yield potential. Rainfall during the growing season was well below normal and during June, July and August only 4.9 inches were recorded. Slightly over 6 inches fell during September, however, this did not overcome the stress from the earlier dry conditions. Samples of these varieties are being stored at the Altman Farm and also at Michigan State University and periodic evaluations of aftercooking darkening will be made throughout the storage period. This technique provides an excellent opportunity to evaluate varieties under grower conditions and this scheme will be used for all overstate trials in 1979. Table 1. The yields specific gravity and chip ratings of several cultivars at three dates of harvest (Montcalm Research Farm). VARIETY August 8 US#1 cwt/A August 8 Specific Gravity August 8 at August 8 Chip Rating** Chip Rating** 3 days later harvest Early and Midseason Denali410 1.094 1 2 August 31 US#1 cwt/A August 31 Specific Gravity August 31 Chip** Rating SEPT. 20 SEPT. 20 Specific Gravity US#1 cwt/A 593 1.102 2 empty table cell empty table cell Atlantic Early and Midseason Michibonne Early and Midseason MS 002-152 Early and Midseason MS 004-408 Early and Midseason MS 108-5 Early and Midseason MS 004-169 Early and Midseason MS 004-377 Early and Midseason Onaway Early and Midseason Tobique Early and Midseason Belchip Early and Midseason Norchip Early and Midseason Superior Early and Midseason MS 002-171 Early and Midseason Jewel Early and Midseason Late Michimac MS 305-19 Late Croatan Late Butte Late FL1227 Late Oneida Late R. Burbank Late FL 945 Late Buckskin Late FL-2 Late FL-774 Late Katahdin Late BelRus Late Monona Late 1.092 435 257 1.070 1.083 265 332 1.085 326 1.074 1.081 304 1.082 281 1.070 406 318 1.079 1.082 333 1.078 279 1.073 265 322 1.076 250 1.078 empty table cell 1 3 3 2 2 3 1 4 2 1 2 2 1 2 1 4 4 2 2 3 3 4 3 2 2 2 1 2 empty table cell 533 511 497 496 488 483 476 431 421 421 415 320 306 302 empty table cell 599 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell591 empty table cell515 empty table cell493 empty table cell429 empty table cell425 empty table cell417 empty table cell398 empty table cell396 empty table cell388 empty table cell378 empty table cell371 empty table cell300 empty table cell293 1.099 1.076 1.088 1.085 1.082 1.087 1.091 1.069 1.081 1.088 1.083 1.075 1.078 1.084 1.075 2 1.088 1.088 1.089 1.083 1.084 1.094 1.082 1.084 1.085 1.084 1.076 1.080 1.072 1 2 1 1 2 2 2 4 2 1 1 2 1 1 2 2 3 1 2 3 1 1 1 1 3 2 1 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 655 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.076 612 624 489 454 439 458 421 400 404 431 515 262 304 1.089 1.071 1.085 1.080 1.078 1.089 1.081 1.083 1.080 1.076 1.077 1.076 1.070 ** Samples were fried at harvest and again at 3 days following harvest. Ratings on the PC/SFA 1-5 scale, with 1 the lightest and 5 the darkest. Table 2. The yield (cwt/A U.S. No. 1) and specific gravity of several varieties at 3 locations. VARIETY Meyers Bay (Aug. 28)US#1 (cwt/A) Meyers Bay (Aug. 28) Chip Rating* Harvest at Meyers Bay (Aug. 28)Specific Gravity Falkeis Delta (Oct. 2) US#1 cwt/A Falkeis Delta (Oct. 2) Specific Gravity Meyers Bay(Aug. 28 Chip Rating* 3 Days After Harvest Beaudoin Houghton (Oct.3) Beaudoi n Houghton (Oct.3) US#1 cwt/A Specific Gravity Atlantic Belchip BelRus Buckskin Butte Centennial Russet Denali FL-2 FL-774 FL-945 FL-1227 Michibonne Michigami Michimac MS 002-171 MS 003-69 MS 004-169 MS 004-198 MS 108-5 MS 305-19 Norchip Oneida Russet Burbank Superior Median** 510 --- --- 330 --- --- 429 338 390 445 442 452 374 507 411 309 429 426 447 --- --- 387 --- 307 426 1.098 --- --- 1.084 --- --- 1.094 1.088 1.086 1.083 1.081 1.078 1.073 1.079 1.083 1.096 1.093 1.086 1.078 --- --- 1.085 --- 1.075 1 — — 2 — — 2 1 1 2 1 1 4 3 1 2 2 1 1 — - 3 2 empty table cell - 3 — — 3 — — 3 2 2 2 1 4 4 4 2 2 3 2 3 — - 3 — 2 --- --- 560 685 388 310 523 510 552 --- --- 632 563 543 446 373 677 490 558 585 460 534 551 466 538 --- 1.081 --- 1.071 1.070 1.081 1.063 1.086 --- --- --- --- 1.064 1.060 1.068 1.070 1.075 1.075 1.073 1.072 1.076 1.078 1.075 1.076 1.070 477 270 356 532 417 392 --- --- --- --- 499 334 452 470 298 551 421 412 424 --- 460 348 357 empty table cell 419 1.092 --- 1.087 1.088 1.089 1.075 1.096 --- --- --- --- 1.075 1.076 1.083 1.080 1.085 1.087 1.082 1.084 1.085 --- 1.082 1.089 1.084 empty table cell empty table cell empty table cell *Samples were fried at harvest at 3 days following harvest. Ratings are on a 1-5 scale with 1 being the lightest and 5 the darkest. **Mid-point at which half of the entries are greater in yield and half are smaller. Table 3. The yield and quality of several varieties grown at the Altman Farm in Presque Isle County Variety Ontario Superior Snowchip Oneida Jewel Atlantic Michibonne Michigami Michimac Total* cwt/A 424 229 360 212 217 279 331 304 335 % over 3 1/4" 10% Specific Gravity 1.065 6% 37% 4% 6% 17% 61% 40% 30% 1.070 1.065 1.080 1.083 1.091 1.066 1.065 1.073 * U.S. No. 1 with a 2 inch minimum. Remarks -not well sized -considerable second growth & heat sprout -considerable feathering - small size -well sized -considerable feathering - small size - small size -uniform size -good appearance -considerable oversize; needs closer spacing -smooth appearance -considerable oversize -smooth appearance -some feathering and trace of scab -good appearance and shape WEED CONTROL IN POTATOES W. F. Meggitt and R. W. Chase Department of crop and Soil Sciences Several combinations of herbicides and time of treatment were applied in Russet Burbank potatoes to control both broadleaved and grass weeds. The primary grass was barnyardgrass and the primary broadleaved weeds were pigweed and lambsquarter. The most effective control of barnyardgrass was obtained from EPTAM at 4-6 lb/a applied preplant incorporated. An application of Sencor or Lexone or Lorox as a delayed preemergence (after weeds emerged and before potatoes emerged pro­ vided the most effective broadleaf control). The combinations of EPTAM and the second application of a chemical for broadleaved weeds provided 100% control. The same treatments that provided 100% weed control also gave the highest yields. The lower yields listed on the table are a reflection of poor or ineffective weed control. The Lasso plus Sencor or Lexone should be used as separate treatments to allow for applying the Lasso at planting (preemergence) and the Sencor/Lexone as a delayed preemergence after weeds have emerged. Delaying the Lasso applica­ tion will give less than effective grass control. Hoelon as a postemergence treatment offers possibility for barnyardgrass control. Preplant Incorporated, Preemergence, and Postemergence Weed Control in Potatoes, Montcalm Co., Michigan, 1978. Planted: May 9 Treated: PPI: May 9 PRE: May 22 POST: June 13 Rated: June 21 Variety: Russet Burbank Soil Type: loamy sand Organic Matter: 2% Weeds Present: Lambsquarter, Pigweed, Barnyardgrass. Rates Ibs/A .5+4 .75+4 4+.5 4+.75 6+2 4+.5 4+.5 6+.5 4+.5 Weed Control Ratings LQ Weed Control Ratings PW Weed Control Ratings BG Injury 8.8 3.7 7.0 7.7 9.8 10 9.0 10 10 10 10 10 10 9.3 4.0 6.7 8.0 9.3 10 9.0 10 10 10 10 10 10 8.8 4.3 7.3 9.0 7.2 9.0 7.3 9.0 10 10 9.7 9.8 10 0.0 0.3 0.0 0.0 2.7 0.0 0.0 0.0 0.0 2.3 0.7 0.7 0.3 cwt/A Total Yield empty table cell empty table cell 314 370 484 380 415 412 437 416 388 419 424 Eptam+(D.PRE) Lexone (PPI) Lexone DF+(POST) (PPI)Eptam+(D.PRE)Lexone DF+(POST)Lexone (PPI)Eptam+(D.PRE)Lexone DF+(POST)Lexone (PPI)Eptam+(D.PRE)Lexone DF+(POST)Lexone 4+3/8+3/8 4+.5+.25 4+.5+.25 4+.5+.25 Tmt. No. Treatment (PPI) R-40244+Eptam (PPI) R-40244+Eptam Eptam+Sencor 4 Eptam+Sencor 4 Eptam+Sencor 4 (PPI) Eptam +(DELAYED PRE) Sencor 4 Eptam+Lexone DF Eptam+Lexone DF Eptam+Lorox 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Preplant Incorporated, Preemergence, and Postemergence Weed Control in Potatoes, Montcalm Co., Michigan, 1978. Continued. cwt/A Total Yield 464 422 430 406 empty table cell empty table cell Tmt. No. Treatment Rates Ibs/A Weed Control Ratings LQ Weed Control Ratings PW Lexone DF R-40244 (PPI) Eptam+(D. PRE) Lexone+Hoelon Lasso+Lexone DF (PRE) Lasso+(D. PRE) Lexone DF (PRE) Lexone DF+Lasso+(POST) R-40244 Lasso+Sencor 4 Lasso+Lexone DF (PPI) Lasso+Lexone DF (D.PRE) Lexone+(POST) Hoelon Lexone+Hoelon (D.PRE) Sencor 4+(POST) Hoelon Sencor+Hoelon Sencor+Hoelon (D. PRE) Sencor 4+Lasso Sencor 4+Lasso No Treatment 4+.5+.75 2.5+.5 2+.5 .5+2+3/8 .75 1 2+.5 2+.5 2.5+.5 .5+1 .5+2 .5+.75 .5+1 .5+.75 .5+2 .5+2.5 --- 10 9.7 10 10 10 10 7.7 9.8 7.0 9.0 9.7 9.3 9.2 9.5 9.3 9.5 0.0 10 9.7 10 10 10 9.7 9.7 10 7.3 8.7 8.7 9.2 9.2 9.2 9.3 9.5 0.0 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. Injury 0.0 0.0 0.0 1.3 0.0 0.7 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.0 Weed Control RatingsBG 9.8 8.3 9.8 10 9.0 6.3 9.3 9.7 6.3 8.7 8.7 9.0 8.7 9.2 8.0 9.0 0.0 414 420 282 397 410 423 445 438 455 432 123 INTERACTIONS BETWEEN COLORADO POTATO BEETLE DENSITY, TIMING OF DEFOLIATION, AND POTATO YIELD E. J. Grafius and C. K. Blakeslee Department of Entomology The study was divided into a large-scale field plot with a natural Colorado Potato Beetle infestation and a series of small caged plots where larval densities were controlled and adult feeding was not allowed. The objective of the field plot was to examine the effects of time of defoliation on yield for early and late varieties of potatoes. In the cage plots we wanted to assess the effects of different larval densities on yield. Field Plot The large-scale field plot was planted to two varieties of potatoes; Sebagos, a late variety, and Norchips, and early-maturing variety. Mean Colorado Potato Beetle density was approximately 5 to 7 larvae and/or adults per hill, much higher than normally found in commercial fields. Portions of the plot were treated with insecticides or left untreated, to manipulate the time of defoliation. For the late-maturing variety, defoliation through July had no significant effect on yield (Fig. 1). Feeding by the summer generation of adults during early August resulted in severe losses. This defoliation may have been more intense than the earlier larval feeding, even though population densities were approximately the same. The relative intensity of adult and larval defoliation needs to be further examined. In contrast, the early-maturing variety never recovered from the early defoliation (Fig. 2). Even in the protected plots, the Norchips had matured and vines were dead by the end of August. Cage Study Eggs were introduced into the cages to provide larval densities of 0, 5, 12, or 25 larvae per hill during the first generation (early July) and again during the second generation (mid-August). There were 10 hills per cage and 5 cages for each density. Half of the plants from each cage were harvested after first generation larval feeding (July 11th) and foliage, stems, and tubers weighed. There are no significant differences in foliage, or tuber weight after 1st generation feeding. Plants were growing vigorously at this time and recovered rapidly from defoliation. The remaining 5 hills in each cage were harvested after 2nd generation larval feeding (August 29th). Tubers, stems, and foliage were again weighed. At this time, when the potatoes were nearly mature, there was a significant reduction in yield of tubers correlated with increased larval density (up to 30% loss - Fig. 3). However, there was no evidence of a threshold density, below which there was no loss in yield. The relationship seemed to be almost linear. Using this relationship, the cost of one spray would be justified at larval densities of 0.5 per hill or higher. Foliage weight was reduced by 29% at the highest larval density. Stem weight was reduced by 22%. Soil moisture seemed to have a considerable effect on the ability of the plant to recover from defoliation. One of the cages (not included in the final analysis) was on the edge of the plot and received inadequate irrigation. Plants in this cage were complete defoliated by 5 larvae per hill. Conclusions 1. Time of defoliation, in relation to variety of potatoes (and presumably date of maturity), was critical in determining the effects on yield. 2. Adult feeding (during mid-August) caused severe defoliation. 3. Yield was reduced nearly linearly with respect to larval density. 4. Factors, such as reduced soil moisture, low soil fertility, or disease, that reduce plant vigor may greatly increase the impact of foliar feeding. The interactions between these factors and the impact of defoliation on potato yield need to be further investigated and should be carefully considered when making recommendations for control of defoliators of potatoes. Fig. 1. Total yield of Sebagos subjected to defoliation by Colorado Potato Beetle adults and larvae for different lengths of time. Fig. 2. Total yields of Sebagos and Norchips subjected to defoliation by Colorado Potato Beetle for different lengths of time. Fig. 3. Tuber yield per plant compared with density of Colorado Potato Beetle larvae. (1.9 lb/plant ≈ 370cwt/a) INFLUENCE OF EXPERIMENTAL NEMATICIDES IN CONTROL OF PRATYLENCHUS PENETRANS AND POTATO YIELDS G. W. Bird and J. Noling Department of Entomology Seven granular and two liquid nematicides were evaluated for control of Pratylenchus penetrans associated with Solanum tuberosum (cv 'Superior') production. A complete randomized block design was used with each treatment replicated 5 times. Seed pieces were planted May 23, 1978 (degree days at base 10C (DD10) = 674) at the Montcalm Potato Research Farm in Entrican, Michigan. Each plot consisted of four rows 15.24 m in length and 0.86 m apart, with 20.5 - 30.5 cm spacing between plants. All nematicides were applied at planting, except NA055 which was applied May 3, 1978 (DD10 = 1035.5). Monitor was applied when necessary for insect control, and irrigation water as needed throughout the growing season. Soil samples for nematode analysis (centrifugation-flotation, 1.14 specific gravity sucrose) were taken immediately before planting, at late mid-season (DD10 = 4702, July 12, 1978) and at harvest on September 1, 1978 (DD10 = 1969). Root samples were processed for nematodes (shaker technique) at DD10 = 5902 and 1969. The center two rows of each plot were harvested, graded and weighed. NA055 significantly (P = 0.05) increased total tuber yield and yield of Grade A tubers. DS16813 resulted in a significant increase in Grade B tubers, without decreasing total tuber yield or yield of Grade A tubers. There were no significant differences in soil population densities of P. penetrans among the plots at DD10 = 674, or among the treatments at DD10= 1384. All treatments significantly reduced P. penetrans root and soil population densities at DD10 = 1969. The sum of the root and soil population densities indicated a significant population decrease with Vydate (DD10 = 1384) and for all treatments (DD10 = 1969). Table 1. Effect of nematicides on Pratylenchus penetrans and potato yields. Pratylenchus penetrans per DD101 No. Pratylenchus penetrans per DD101 No. Pratylenchus penetrans per DD10 1 Treatment, formulation and rate per acre Check (non treated) DS 16813 - 4 lb ai/acre DS 16813 - 2 lb ai/acre Vydate 106 - 2 lb ai/acre Mocap 10G - 2 lb ai/acre Mocap 6EC - 2 lb al/acre RH 4553 5G 14 lb/acre RH 7346 5G 14 lb/acre RH 308 5G 14 lb/acre NAO 5510 10 gal/acre Pratylenchus penetrans per DD10 1 No. per 100 cm3 soil 10 1 No. per 100 cm 3 soil Pratylenchus penetrans per DD 674 1384 per 100 cm3 soil 1969 per g root 1384 Pratylenchus penetrans per DD101 No. per g root 1969 No. per g root Pratylenchus penetrans per DD10 plus No. per 100 cm 3 soil 1 No. per g rootplus No. per 100 cm3 soil 1969 1384 Tuber yield (ctw per acre) A Grade Tuber yield (ctw per acre) B Grade Tuber yield (ctw per acre) Oversize Grade Total Tuber yield (ctw per acre) 19.8a 2 42.146a 54.20b 38.4a 22.4a 20.6a 11.2a 16.8a 12.4a 20.2a 12.0a 15.8a 31.036a 12.20a 8.816a 2.150a 17.704a 15.482a 3.20a 2.80a 4.40a 5.40a 26.592a 10.00a 42.146a 17.704a 15.882a 8.60a 12.20a 10.20a 31.4a 15.6a 15.2a 11.4a 7.4a 14.0a 14.0a 25.2a 15.8a 8.4a 38.0b 9.2a 10.2a 5.6a 6.0a 9.8a 8.4a 5.2a 14.8a 7.2a 73.544b 92.2b 47.034ab 21.4a 22.014ab 13.4a 8.4a 13.54a 21.102ab 10.4a 29.48ab 15.2a 18.4a 40.59ab 67.344ab 13.8a 33.502ab 27.2a 17.4a 23.88ab 185.2a 190.1a 206.8a 196.0a 201.2a 194.2a 183.5a 191.1a 180.5a 236.7b 5.5a 6.3a 6.6a 9.9b 7.0a 7.2a 5.6a 6.1a 6.3a 5.1a 12.2a 13.4a 14.0a 9.8a 11.5a 13.9a 11.7a 16.3a 9.6a 21.0a 202.9a 209.8a 227.4a 215.7a 219.9a 215.3a 200.8a 213.5a 196.4a 262.8b DD10 = degree day accumulation base 10 C. 1) 2) Column means followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman Keul Multiple Range Test. POTATO INSECT CONTROL STUDIES A. L. Wells Department of Entomology A. Soil Insecticide Evaluation for White Grub Control Wireworms and white grubs often cause extensive feeding damage to potato plants especially to the tubers. This damage usually results in the lowering of grade or rejection of the crop by the buyer. These insects are usually most severe when new fields, especially grassy areas, are brought into pro- duction. Past research programs have evaluated several insecticides for wireworm control some of which are labeled and are now being recommended for this use. There are no control programs available when white grubs are the principal problem. Methods A plot to evaluate 27 different treatments including different combinations of experimental and registered insecticides on soil insects was established at the Cranney Farm in Mecosta County. The plot was located in a field which had been out of production several years and grasses and weeds had become established. An early inspection of the area indicated white grubs were present. 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 the insect damage in each treated row could be compared with an adjacent untreated row. This plot lay-out was elected to assume adequate evaluation of the data since past research indicated that soil insect populations are seldom evenly distributed over an area. Five foot alleys were left untreated between the replications. The broadcast applications were distributed as granules or in water solutions over the soil surface and rototilled to a depth of 6 to 8 inches. The band treatments were applied in the seed furrow and then covered by hand. The preplant treatments were applied on May 21 and the band treatments applied in the seed furrow at the time of planting on May 22. They were covered immediately after. Russet burbank seed were used in the plot. The plots were fertilized and maintained by the grower similar to the rest of the field. The alleys between the plots were opened up by hand prior to harvesting with the plot mechanical harvester. Vine killers had been applied to facilitate use of the equipment. The plots were harvested and on October 11 and placed in tagged bags. These were then taken to a storage shed and held until further analyzed. All of the tubers were graded by size and white grub and wireworm damage was evaluated. Each of the grades and damage classifications were weighed before discarding. Samples were saved from each treated plot for specific gravity determination or residue analysis. All of the tubers from the unlabeled treatments or damaged by insects were discarded and the rest were saved for further use. The results of the tuber evaluations are presented in Table 1. Table 1. Yields and insect tuber damage data from soil insect research plot, Morley, Michigan Planted: May 22; Harvested: October 1978 Percent Tubersby Grade Size B's Rate ai/A Yield/A Placement Material and Percent Tubers by Grade Size A's Percent Tubers by Grade Size 10oz Percent Percent Tubers Percent Tubers Damaged TubersDamaged Damaged Grub Wireworm Off Percent Tubers by Grade Size Specific Gravity Good NC-6897 76W NC-6897 76W Untreated NC-6897 76W NC-6897 76W Untreated NC-6897 76W + Temik 15 G 15 G Untreated NC-6897 76W + Temik NC-6897 76W + Furadan 10 G NC-6897 76W + Furadan 10 G Untreated Mocap 6 EC Mocap 6 EC Untreated Mocap 6 EC Mocap 6 EC Untreated Mocap 6 EC + Temik 15 G Mocap 6 EC+ Temik 15 G Untreated Mocap 6 EC + Furadan 10 G 10 G Untreated Mocap 6 EC + Furadan Dyfonate 10 G 10 G Untreated Dyfonate Dyfonate 10 G + Temik 15 G Dyfonate 10 G+ Temik 15 G Untreated Dyfonate 4 E 4 E Untreated Dyfonate Seed Treat -- Brdcst -- Brdcst Band -- Brdcst Band -- Brdcst -- Brdcst -- Brdcst Band -- Brdcst Band -- Brdcst -- Brdcst Band -- Brdcst -- 4 oz ai/ 100 lb -- 4 lb -- 4 lb 3 lb -- 4 lb 3 lb -- 3 lb -- 6 lb -- 3 lb 3 lb -- 3 lb 3 lb -- 4 lb -- 4 lb 3 lb -- 4 lb -- 321 cwt 372 378 353 398 -- 396 316 -- 371 367 386 351 382 341 400 372 414 343 369 308 396 370 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 17 66 72 19 72% 70 21 68 17 13% 6% 9% empty table cell empty table cell 5 6 empty table cell empty table cell 7 8 empty table cell empty table cell empty table cell 6 5 empty table cell empty table cell 6 7 empty table cell empty table cell 4 9 empty table cell empty table cell 7 7 empty table cell empty table cell 8 6 empty table cell empty table cell 5 7 empty table cell empty table cell 9 empty table cell 3 empty table cell empty table cell empty table cell 18 70 68 16 13 6 6 75 67 12 19 75 73 17 1.089 1.089 1.087 1.091 1.088 1.087 96.8% empty table cell 93.5 95.7 empty table cell 94.0 98.1 empty table cell 94.8 97.8 empty table cell 90.9 97.7 empty table cell 94.3 96.8 95.4 empty table cell 96.3 empty table cell 95.8 97.6 empty table cell 93.0 99.6 95.4 empty table cell 97.9 empty table cell 95.0 95.4 91.7 empty table cell 1.087 1.090 1.089 1.089 1.091 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 3.1% 3.5 3.7 3.6 1.3 3.5 1.9 5.5 2.1 4.6 3.2 3.1 3.1 3.2 2.1 5.1 0.2 4.0 1.7 3.3 4.2 6.6 0.1% 3.0 0.6 2.4 0.6 1.7 0.3 3.6 0.2 1.1 0 1.5 0.6 1.0 0.3 1.9 0.2 0.6 0.4 1.6 0.4 1.6 Material and Placement Rate ai/A Yield/A Percent Tubers by Grade Size Percent Tubers Percent Tubers by Grade Size by Grade Size A’s 10 oz B’s Percent Tubers Percent Tubers Damaged Damaged Wireworm Off Percent Tubers by Grade Size Grub Specific Gravity Good Percent Tubers Damaged Dyfonate 4 E + Temik 15 G 15 G Untreated Dyfonate 4 E + Temik Dyfonate 4 E + Furadan 10 G Dyfonate 4 E + Furadan 10 G Untreated Dasanit 15 G 15 G Untreated Dasanit Dasanit 15 G + Temik 15 G 15 G Untreated Dasanit 15 G + Temik Dasanit 15 G + Furadan 10 B 10 B Untreated Dasanit 15 G+ Furadan Dasanit 6 E Dasanit 6 E Untreated Dasanit 6 E + Furadan 10 G 10 G Untreated Dasanit 6 E+ Furadan Diazinon 4 E Diazinon 4 E Untreated Diazinon 4 E + Temik 15 G Diazinon 4 E + Temik 15 G Untreated Diazinon 4 E + Furadan 10 G Diazinon 4 E + Furadan 10 G Untreated Furadan 10 G Furadan 10 G Untreated Brdcst Band -- Brdcst Band -- Brdcst -- Brdcst Band -- Brdcst Band -- Brdcst -- Brdcst Band -- Brdcst -- Brdcst Band -- Brdcst Band -- Brdcst -- 4 lb 3 lb -- 4 lb 3 lb -- 5 lb -- 5 lb 3 lb -- 5 lb 3 lb -- 5 lb -- 5 lb 3 lb -- 4 lb -- 4 lb 3 lb -- 4 lb 3 lb -- 3 lb -- 300 cwt 304 371 362 424 345 385 383 444 323 416 362 403 370 361 311 369 404 373 358 380 363 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 19 empty table cell empty table cell 20 15 15 18 18% 7% empty table cell 8 empty table cell 8 empty table cell 7 empty table cell 7 empty table cell 6 empty table cell 6 empty table cell 7 empty table cell 6 empty table cell 6 empty table cell 68% 7% empty table cell 5 67 empty table cell 6 71 empty table cell 68 10 empty table cell 8 67 empty table cell 4 71 empty table cell 7 69 empty table cell 4 72 empty table cell 8 66 empty table cell 7 65 empty table cell 2 empty table cell empty table cell 20 18 70 21 17 22 7 1.089 1.089 1.087 1.090 1.088 97.9% empty table cell 94.6 97.8 empty table cell 92.6 98.2 empty table cell 93.0 98.6 empty table cell 96.8 97.4 empty table cell 94.8 98.1 empty table cell 94.7 98.8 empty table cell 95.7 97.4 empty table cell 94.8 95.9 empty table cell 94.0 98.9 empty table cell 94.1 96.0 empty table cell 94.7 1.086 1.088 1.087 1.086 1.088 1.089 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1.9% 4.0 1.1 4.9 1.0 5.3 0.7 2.2 2.3 2.4 1.3 3.7 1.1 3.5 1.7 3.4 3.5 5.0 0.4 3.2 2.6 3.4 0.2% 1.5 1.0 2.5 0.8 1.7 0.7 1.0 0.3 2.8 0.6 1.5 0.1 0.8 0.9 1.9 0.7 1.0 0.7 2.7 1.3 1.9 Material and Placement Rate ai/A Yield/A Percent Tubers by Grade Size B’s Percent Tubers by Grade Size A’s Percent Tubers by Grade Size 10 oz Percent Percent Tubers TubersDamaged Damaged Grub Wireworm Percent Tubers by Grade Size Off Specific Gravity Good Percent TubersDamaged Band -- Band -- Furadan 10 G 3 lb -- Furadan 10 G Untreated Temik 15 G 3 lb -- Temik 15 G Untreated Untreated Controlempty table cell-- empty cell table-- Untreated Untreated Controlempty table cell Untreated Untreated Controlempty table cell Untreated empty cell table-- empty cell table-- -- -- 396 cwt 383 389 383 351 327 373 326 382 261 66% 21% 6% empty cell table 8 empty cell table 7 empty cell table 7 empty cell table 7 empty cell table 7% empty cell table 4 empty cell table 5 empty cell table 2 empty cell table 5 empty cell table 18 15 73 15 69 70 76 1.090 1.087 1.089 98.2% empty cell table 96.7 94.8 empty cell table 92.7 94.4 empty cell table 91.6 95.4 empty cell table 96.2 91.6 empty cell table 93.8 1.088 1.087 empty cell table empty cell table empty cell table empty cell table 19 empty cell table empty cell table empty cell table empty cell table empty cell table empty cell table 1.2% 2.9 4.4 5.0 3.9 5.8 3.0 2.5 4.1 5.0 0.6% 0.5 0.8 2.3 1.7 2.5 1.5 1.2 4.3 1.2 *Placement: Seed Treat = Seed treatment; Brdcst = Broadcast and incorporated; Band = In-row with seed. Rates based on 34 inch rows; liquids and wettable powders applied in water at 50 gal. per A. Results The populations of white grubs was not as severe as anticipated in the plot areas thus the tuber damage was much less than was expected. The damage as measured by percent by weight of tubers showing grub feeding scars varied from 2.4% to 6.6% in the untreated rows compared to 0.2% to 4.4% damage in the adjacent treated plots. The data have not been analyzed statistically however so the differences may not be statistically significant. This type of treatment evalua- tion exemplifies the problems associated with predicting and evaluating soil insect problems. B. Foliar Insecticide Evaluation at Muck Experimental Farm Several commercial and experimental materials were evaluated for the foliar insects associated with potato production in Michigan. Data on cutworm control were especially needed to complete requirements to extend label coverage of certain materials. Colorado potato beetle, potato leafhoppers and aphid popula- tions developed in the plot and excellent data were obtained on insecticide performance on them (Tables 2-5). Yield data did not reflect these differences, however, (Table 6). Muck grown potatoes if provided good cultural practices can withstand high insect populations without substantially affecting the yield. Table 2. Foliar Insect Control on Potatoes Potato Leafhoppers (Insects/30 Sweeps) July August Material a Bendiocarb WP 1/2 Bendiocarb WP 1 Bendiocarb SC Monitor Lannate GCP 6361 UC 51762 Furadan F Pydrin Sandoz 6538 Temik Dacamox 2 Dacamox 3 Furadan G Furadan G + F Furadan G + Pir Untreated Untreated July 12 12 15 25 13 12 21 24 23 17 12 4 -- 2 8 10 3 14 13 24 54 21 18 20 19 31 13 24 2 36 13 9 7 13 39 52 39 70 August 16 12 2 6 8 7 23 5 3 3 16 21 10 6 18 6 17 11 25 August 29 44 60 39 43 60 67 34 39 20 49 51 45 19 44 39 57 50 39 7 79 20 25 25 42 68 18 42 6 53 35 15 18 32 43 36 48 66 a For rates of application and treatment dates refer to harvest data. Table 3. Foliar Insect Control on Potatoes Flea Beetles (Insects/30 Sweeps) Material a Bendiocarb WP 1/2 Bendiocarb WP 1 Bendiocarb SC Monitor Lannate GCP 6361 UC 51762 Furadan F Pydrin Sandoz 6538 Temik Dacamox 2 Dacamox 3 Furadan G Furadan G + F Furadan G + Pir Untreated Untreated July July 24 69 33 23 71 76 87 12 31 6 84 104 70 32 84 87 82 52 100 12 5 13 17 10 4 21 18 9 17 16 32 16 11 28 24 24 33 13 August 7 Auguts 181 67 97 181 202 253 76 165 161 158 343 463 99 82 81 95 91 95 16 8 2 4 6 4 8 0 1 2 11 39 66 15 28 4 14 22 37 August 29 28 21 34 15 31 18 18 15 22 19 14 6 16 18 10 14 11 22 a For rates of application and treatment dates refer to harvest data. Table. 4. Foliar Insect Control on Potatoes Colorado Potato Beetle (Insects/30 Sweeps) Material a Bendiocarb WP 1/2 Bendiocarb WP 1 Bendiocarb SC Monitor Lannate GCP 6361 UC 51762 Furadan F Pydrin Sandoz 6538 Temik Dacamox 2 Dacamox 3 Furadan G Furadan G + F Furadan G + Pir Untreated Untreated July 12 July 12 Ad Lv 0 207 1 203 0 188 192 0 207 1 2 208 2 188 144 1 316 0 238 0 0 1 1 11 0 1 4 0 0 9 2 2 2 191 134 1 July 24 Ad 0 0 1 1 0 0 2 1 1 1 0 1 1 1 1 2 2 0 July 24 Lv 2 2 0 15 40 1 56 0 1 0 2 6 1 42 80 38 61 21 Aug 7 Ad 66 79 61 72 69 27 58 56 65 52 24 27 9 16 33 37 126 66 Aug 7 Lv 2 0 2 0 3 0 11 0 1 0 1 2 2 35 25 23 33 9 Aug 16 Ad 2 2 1 2 24 3 15 2 16 1 12 7 3 12 1 15 40 24 16 Aug Lv 0 0 0 0 7 0 4 0 5 1 5 1 3 6 0 8 13 7 Aug 29 Aug 29 Ad Lv 0 15 1 5 6 0 16 0 1 5 1 3 3 11 2 1 0 11 2 0 21 0 0 27 12 1 2 5 1 0 2 9 6 3 4 1 Total % 13 1 2444 99 15 4 368 96 943 86 149 14 182 75 60 25 16 9 161 91 aFor rates of application and treatment dates refer to harvest data. Table 5. Foliar Insect Control on Potatoes Green Peach Aphids (Insects/30 Sweeps) Material a Bendiocarb WP 1/2 Bendiocarb WP 1 Bendiocarb SC Monitor Lannate GCP 6361 UC 51762 Furadan F Pydrin Sandoz 6538 Temik Dacamox 2 Dacamox 3 Furadan G Furadan G + F Furadan G + Pir Untreated Untreated July 12 3 5 13 12 7 9 10 13 3 7 2 5 4 19 5 27 9 7 July 24 137 174 184 16 22 6 82 16 7 6 10 15 10 101 194 252 116 134 August 16 175 288 495 4 10 5 218 10 12 247 27 60 164 153 35 18 62 35 7 August 422 322 912 26 67 17 312 116 18 132 26 88 156 413 543 332 116 133 August 29 5 6 79 8 7 2 145 4 1 7 4 5 3 8 112 10 4 6 Aphids/15 leaves Aphids/15 leaves Aug 7 Aug 23 65 111 211 2 11 7 50 21 3 42 11 6 26 106 62 160 25 40 11 190 257 0 5 0 35 11 0 139 0 1 22 2 28 2 2 2 a For rates of application and treatment dates refer to harvest data. Table 6. Yields and Size of Tubers from Potato Foliar Plots MSU Muck Exptl. Farm, Bath (Clinton Co.) Variety: Sebago Date Planted: May 17; Date Harvested: Oct. 9 Materials Bendiocarb 76 WP Bendiocarb 76 WP Bendiocarb 50 S Monitor 4 WDL Lannate 1.8 L Gulf GCP 6361 2 EC Un. Carb. 51762 75 WP Furadan 4 F Pydrin 2.4 EC Sandoz 6538 2 EC Temik 15 G Dacamox 15 G Dacamox 15 G Furadan 10 G Furadan 10 G + Furadan 4 F Furadan 10 G + Pirimor 50 W Untreated Untreated Rate/A (Tox.) 1/2 lb 1 lb 1 lb 3/4 lb 0.9 lb 1 lb 0.9 lb 1 lb 0.1 lb 1/2 lb 3 lb 2 lb 3 lb 3 lb 3 lb 1 lb 3 lb 1/4 lb -- -- Plcemnt a Fol Fol Fol Fol Fol Fol Fol Fol Fol Fol In-row In-row In-row In-row In-row Fol In-row Fol -- -- Yield/Acre b Yield/Acre b Bu Cwt 458 275 296 493 445 267 244 407 412 247 522 313 252 420 246 410 256 427 412 247 230 383 267 445 206 343 477 286 447 268 264 440 316 527 438 263 % Size Distribution % Size Distribution 1-7/8" and Less Than 1-7/8" 10% 12 12 11 13 8 10 11 14 12 13 11 15 12 Over 90% 88 88 89 87 92 90 89 86 88 87 89 85 88 87 83 91 89 13 17 9 11 a Type of foliar applications: CO2 sprayer delivering 70 gal./A. applied on July 18, 24, Aug. 12 and 29. Granular treatments applied in row at time of planting. b Plots consisted of three replications of paired 25 ft. rows. EFFECT OF POTATO SEED PIECE TREATMENT ON STAND AND YIELD -1978 Department of Botany and Plant Pathology H. S. Potter Chemicals alone or in combination were compared as potato seed piece treat- ment for control of tuber dry rot and black leg (soft rot). Seed of the variety Sebago was cut and chemically treated immediately prior to planting on May 9, 1978. Chemicals were applied either by lightly dusting seed pieces or by dipping them for two minutes. Treatments were randomized and replicated four times in a single block planting. Plots consisted of a single row 50 feet long. The row width was 34 inches with seed spaced 12 inches apart within rows. Seed was slow to sprout and the plant stand in general was poor. Stand count and yields varied widely within treatments. Differences between treatments were not found to be significant except where the seed was soaked in water before planting. The water alone tended to increase seed piece decay. Yield CWT/A Yield CWT/A Treatment % Stand US #1 B Grade 1. Clorox 5.25% (sodium hypochlorite) 1.9 w/water 2. Chlorine dioxide 50 ppm 3. Chlorine dioxide 100 ppm 4. CGA 14703 100 ppm 5. Terraclor Super X 5% dust 6. Terraclor Super X 10% dust 7. Terraclor 5% dust 8. Terraclor 10% dust 9. Topsin M 2 1/2% dust 10. Topsin M + Dithane M-45 1% + 5% dust 11. Water 12. No Treatment LSD .05 74.2ab 79.5ab 80.1ab 75.0ab 71.8 b 69.2 b 80.5ab 76.0ab 80.6ab 280.4 b 285.0ab 287.5ab 289.0ab 290.1ab 278.7 b 291.4ab 285.0ab 303.5a 83.6a 50.1 c 67.8 b 305.0a 251.8 c 283.2 b 12.2 24.0 6.5 7.1 4.5 7.1 8.6 5.1 6.3 7.2 7.0 6.8 5.7 6.5 NS Small letters indicate treatments that do not differ significantly at 5% level according to the LSD test. EFFECT OF PRE-PLANT SOIL TREATMENTS ON THE CONTROL OF POTATO SCAB - 1978 Department of Botany and Plant Pathology H. S. Potter Terraclor, a nitrate inhibitor (Terrazole) and combinations of both were applied as pre-plant soil treatments for control of scab on potatoes. Terraclor alone was broadcast and applied tn the rows. Terrazole plus urea with and without the addition of Terraclor was applied only as a broadcast treatment. The soil type was a fine sandy loam with a pH of 7.2. It was heavily inocu- lated with the scab organism in the fall of 1977. Irrigation was used only when necessary to maintain growth. Plots were mechanically weeded and were sprayed weekly for foliar disease and insect control. Cut seed variety Sebago was planted May 12, 1978, in single row plots 25' long. The row width was 32" with seed pieces spaced 9" apart within rows. Treatments were arranged in a randomized block planting with three replications. Terraclor alone and in combination with Terrazole plus urea was effective in reducing scab. Terrazole plus urea alone had no beneficial effect on disease incidence. In-row applications of Terraclor 2 EC resulted in the highest mar­ ketable yields. Treatment U.S.#1 Yield cwt/A Harvested Harvested B Grade Marketable U.S.#1 Yield cwt/AMarketable B Grade Yield cwt/A Yield cwt/A % Marketable 1 Tubers 1. Terraclor 2 EC 12 1/2 gal/A -Broadcast 2. Terraclor 2 EC 18 3/4 gal/A -Broadcast 3. Terraclor 2 EC 5 gal/A - in row 4. Terraclor 2 EC 7 1/2 gal/A in row 5. Terraclor 75W 33 Ib/A -broadcast 6. Urea + Terrazole 100D+ 100 IbN + 1/2 lb ai/A - Broadcast 7. Urea + Terrazole 100D 100 N + 1 lb ai/A - Broadcast 8. Urea + Terrazole 100D+ Terraclor 2 EC 100/lb N + 1/2 1b ai + 12 1/2 gal/A - Broadcast 9. Urea + Terrazole 100D+ Terraclor 2 EC 100 lb N + 1 lb ai + 12 1/2 gal/A - Broadcast 10. No treatment 287.8 37.0 183.9a 23.6a 299.8a 307.8a 53.7 18.5 206.3b 36.9 b 229.9a 13.8a 308.2a 25.4 291.1a 62.4 241.0a 19.9a 212.2b 45.5b 63.9 b 68.8 b 74.7a 78.2a 72.9ab 277.9a 47.9 87.0d 15.0a 31.3 c 282.8a 49.7 85.7d 15.1a 30.3 c 285.6a 34.8 179.1c 21.8a 62.7 b 294.0a 254.5b 32.3 54.8 197.3b 65.2e 21.7a 14.0a 67.1 b 25.6 c Small letters indicate Duncan's multiple range groupings of treatments that do not differ significantly at the 5% level. 1 Potato tubers with less than 2% scab. Note: Treatments 1 through 6 and 10 also received 100 lbs. of N in the form of urea. FUNGIGATION TRIALS WITH BRAVO 6F FOR DISEASE CONTROL ON POTATOES Department of Botany and Plant Pathology H. S. Potter The fungicide Bravo 6F applied on potatoes at the recommended rate (1 1/2 oz/ A) with a boom sprayer and through solid set irrigation was evaluated for control of early blight (Alternaria solani) and Botrytis blight (Botrytis cinerea). Trials were conducted on commercial plantings of Onaway and Sebago potatoes at the Ferris Christenson farm in Montcalm County. The experimental site was a 60 acre irrigated field with sandy loam soil and moderately undu- lating topography. The field was about equally divided between the two potato varieties. Treatments were applied to adjacent blocks which varied in size from 25 acres for the boom sprayer to 5 acres for the irrigation method. Cultural practices including the use of irrigation and the application of herbicides and insecti­ cides were uniform throughout the plantings. The boom sprayer (J. Bean) used was trailer-mounted and covered 12 rows. Nozzles were the flat fan type (Spraying Systems #6502) spaced 12 inches apart and without drops. The irrigation system had 4-foot risers laid out on 60-foot centers. The sprinkler heads (Buckner #8601) fitted with 7/16" orifices were operated at 75 psi. The spray suspension, a 20 X concentration, was introduced into the irrigation system at 120 spi using a power sprayer and a fertilizer injector. Dye, red #46 (H. Kohnstam), was added initially to the spray suspension to determine the time required to apply the fungicide treatments. This varied between 20 and 25 minutes for 5 acres, depending on the topography of the area treated and other factors. The estimated volume of water applied by the irrigation method varied between 950-1200 gallons per acre as compared to 50 gallons per acre with the boom sprayer. Fungicide treatments were started during the third week in June and continued on a 7-day schedule until the middle of September (12 applications). Evaluation for disease incidence and yield were made in .04 acre plots arranged in replicated transects extending across the treated areas. Adequate unsprayed checks were provided for comparison. Summary: In both trials, Bravo 6F was equally effective against early blight irrespective of method of application. It was also effective against Botrytis blight, but control was significantly better by the irrigation method than with the boom sprayer. Of the two methods, it is apparent that the irrigation system provided better distribution of the fungicide, particularly on the lower portions of the potato plants where Botrytis blight was most severe. Sprayer wheel track damage was a significant factor affecting both disease incidence and yield. The effect on disease incidence was particularly notice- able with Botrytis blight in the Onaway trial and with early blight in the Sebago trial. The prorated loss in yield of US #1 potatoes from sprayer wheel damage for both trials averaged about 9%. Table #1 - Variety Onaway Method of Application Early Bl. Botrytis Bl. US #1 B Grade Disease Index 2, 3 Index 2, 3 Disease Average Yield CWT/A 3 Yield CWT/A 3 Average Boom Sprayer (NWT) 1 Boom Sprayer (WT) 1 Irrigation No treatment 1.7 ab 2.2 b 1.5 a 2.9 b 3.7 c 1.8 a 5.1 c 4.0 c 312.6 a 251.5 b 303.0 a 238.3 b 59.6 a 49.4 a 38.4 a 37.0 a Table #2 - Variety Sebago Disease Index Disease Index 2, 3 Average Yield CWT/A 3 Average Yield CWT/A 3 Method of Application 2, 3 Early Bl. Botrytis Bl. US #1 B Grade Boom Sprayer (NWT) 1 Boom Sprayer (WT) 1 Irrigation No treatment 1.5 a 2.0 b 1.6 a 2.4 b 2.9 bc .9 a 4.8 c 3.5 c 348.7 a 288.6 c 352.1 a 309.4 b 61.1 a 54.8 a 59.2 a 50.5 a 1 NWT = non-wheel track rows, WT = wheel-track rows. 2 Disease Index: 0 = no disease; 10 = 100 % foliage infected. 3 Small letters are Duncan multiple range groupings which do not differ significantly at the 5% level. COLORED BEAN VARIETY AND STRAIN TEST M. W. Adams, A. W. Saettler, J. Taylor Department of Crop and Soil Science These tests were seeded June 13 under somewhat non-uniform soil mois- ture conditions. Emergence was not complete until June 30. Row width was 20 inches, plots 3 rows wide, in 4 replications. The nursery received one irrigation at mid pod fill for Charlevoix which seemed to benefit the standard full-season varieties, but it apparently was too late to help the earlier-maturing entries. Primarily on account of seed quality and color, seven of the 29 entries were not harvested. For tabular purposes, the standard varieties and the experimentals are presented in two different tables. However, in fact, all entries were grown interspersed in a common field nursery, so their yields may be directly compared. Test 8201-SV. Standard large colored beans. Variety Charlevoix Mecosta Manitou Sacremento Redkloud Montcalm Valley Yellow-Eye Swedish Brown Michicran Seed Type DRK LRK LRK LRK LRK DRK Great Northern Y.E. Sw. Br. Cranberry LDS.05 = 107 lbs. Test 8201 - Exp. Yield in lb/acre 1818.3 1883.6 1930.3 1357.2 1426.8 1915.1 1360.5 1070.1 1187.6 1457.2 Entry 70699 5406 70702 70688 5408 70689 70700 6854 61144 70710 70684 6831 Seed Type Desirability Yield in lbs/acre LRK LRK LRK LRK Large White LRK LRK LRK Large White DRK LRK DRK B A A B B B A C A A+ B B 1185.4 1783.5 1178.8 1682.4 1425.7 964.6 1434.4 1625.8 2179.4 1327.8 1676.9 1262.6 LSD.05 = 107 lbs. Discussion of Tests 8201-SV and 8201-Exp: The four full-season red kidney varieties were significantly the best yielders at this site, Charlevoix not quite up to the others. The early light reds, Sacremento and Redkloud, were clearly too early to yield well at this location and planting date. In the test 8201-Exp. only early maturing lines were included, all with halo blight resistance. Seven lines were not harvested because a preliminary check of seed coloration at maturity indicated they would be unacceptable to processors. The 7 lines underscored in the table appear the most promising. They include 2 large white-seeded types, one dark red kidney, and 4 light reds. Since the first objective of this nursery was to identify a mid-early light red, we shall have to rely upon one of the lines 5406, 70688, 70700, and 6854 as potential replacement for the margin- ally late Mecosta. Of these, 5406 came closest in yield to Mecosta, although much earlier in maturity. CONTROL OF THE ROOT-LESION NEMATODE (Pratylenchus penetrans) ASSOCIATED WITH NAVY BEAN (Phaseolus vulgaris L.) YIELDS -1978 G. W. Bird and A. P. Elliott Department of Entomology Seven nematicides were evaluated. Each treatment was replicated six times in a randomized block design on a sandy clay loam soil (s = 66.4, si = 11.08, c = 22.5) at the Michigan State University Montcalm Experimental Farm in Entrican. Each plot consisted of 4 rows 6.0m (20 ft) in length and 0.86m (34 inches) apart. Three fumigant nematicide treatments of Nemamort 8E were applied (in-row) 19 days before planting (DD10 = 309). The non-fumigant nematicides were applied (in-row) at the time of planting on June 21, 1978 (DD10 = 540). Soil samples were taken prior to the application of the soil fumigants, and at the time of planting. Soil and root samples were taken at 6 intervals from time of planting until harvest. The centrifugation-flotation and shaker techniques were used to determine P. penetrans population levels in soil and roots, respectively. Nematode populations in the soil were not significantly different (P = 0.05) at the time of fumigation with Nemamort at 309 accumulated degree days at a base of 10 C (DD10 = 309). At the time of planting (DD10 = 540), however, nematode populations in plots fumigated with Nemamort were significantly lower (P = 0.05) than those in all other plots. Both soil and root populations fluctuated throughout the growing season in accordance with the life cycle of P. penetrans. The greatest population density of P. penetrans was recovered from roots at mid- season (DD10 = 1877). Three generations of P. penetrans occurred during the growing season. All chemical treatments significantly reduced population densities of P. penetrans. Yields of dry navy beans were increased over that of the control with Temik 15G at 0.75 lb ai/acre, Temik 15G at 1.50 lb ai/acre, and Vydate 10G at 3.0 ai/acre. There was no significant difference between yields from plots treated with Nemacur 15G and the control plot. All Nemamort treatment significantly reduced yields below that of the control. There was no significant difference among yields from the three Nemamort treatments. Nemamort at 36 lb ai/acre produced the lowest yield. Table. 1. Effect of nematicides on populations of Pratylenchus penetrans and on yield of navy beans. Treatment, formulation and rate per acre Yield cwt/acre Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD 10*No. per 100 cm 3/soil Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD10*No. per g root tissue Pratylenchus penetrans at DD10*No. per g root tissue Pratylenchus penetrans at DD10*No. per g root tissue Pratylenchus penetrans at DD10*No. per g root tissue Pratylenchus penetrans at DD10*No. per g root tissue 10* No. per 100 cm Pratylenchus penetrans at DD 3/soil 309 890 Pratylenchus penetrans at DD 10* No. per 100 cm 3/soil 540 1349 1877 2167 2288 2340 890 1349 1877 2167 2288 Pratylenchus penetrans at DD 10* No. per g root tissue 2340 Check 19.2c Temik 15G 0.75 lb ai/acre 22.5d Temik 15G 1.50 lb ai/acre 24.4d Vydate 10G 3 lb ai/acre 24.8d Nemamort 8E 18 Ib/acre 16.8bc Nemamort 8E 24 lb/acre Nemamort 8E 36 lb/acre 14.5b 10.0a 54a 52a 59a 51a 65a 53a 52a 56b 59b 55b 18a 11a 7a Nemacur 15G 5 lb ai/acre 16.9bc 46a 54b *DD 10 = accumulated degree days (base 10 C) 57b 65b 24ab 46b 13a 4a 7a 13a 14a 7a 11a 23b 5a 1a 7a 6a 1a 5a 1a 49b 5a 11a 14a 7a 7a 11a 4a 30b 8a 13a 7a 8a 8a 13a 4a 79c 69b 105b 32b 67b 27c 3ab 3ab 3ab 10b 5ab 5ab 1a 0a 1a 4a 9a 3a 2a 0a 2a 5a 8a 16a 17a 20a 6a 1a 0a 1a 1a 1a 1a 1a 5a 2a 3a 4a 11a 5a 4a 6ab 2a 2a 11ab 19bc 18bc 2a 7a 14a 12a 17a 19a 12a 9a 2a 1a 1a 1a 2a 5a 1a Column means followed by the same letters are not significantly different according to the Student-Newmans-KeuIs Multiple Range Test (P = 0.05). CONTROL OF THE ROOT-LESION NEMATODE (Pratylenchus penetrans) ON SOYBEANS (Glycine max), 1978 G. W. Bird and A. P. Elliott Department of Entomology Four nematicide treatments were evaluated, and each nematicide treatment was replicated five times in a randomized block design. The experiment was carried out on a sandy clay loam soil (s = 66.4, si = 22.4, c = 11.08) at the Michigan State University Montcalm Experimental Farm in Entrican. Each plot consisted of 4 rows 6.0m (50 ft) in length and 0.86m (34 inches) apart. All nematicides were applied (in-row) at the time of planting on June 6, 1978 (accumulated degree days at a base of 10 C, DD10 = 368). Soil samples were taken at the time of planting, and soil and root samples were taken at 5 intervals throughout the season. Soil and root samples were analyzed by the centrifugation- flotation and shaker techniques, respectively, and population densities of P. penetrans calculated. There was no significant (P = 0.05) difference among the plots in the initial soil population densities of P. penetrans (DD10 = 368). All treatments significantly reduced both soil and root population densities of P. penetrans. Population densities fluctuated thoughout the growing season. The highest P. penetrans densities in the root tissue was found 58 days after planting (DD10 = 1349), while population densities in the soil were highest at the time of harvest (DD10 = 2360). Treatment with Temik 15G at 2.0 lb ai/acre and Nemacur 15G at 5.0 lb ai/acre resulted in significant increases in bean yields. Table 1. Effect of nematicides on population densities of Pratylenchus penetrans and on soybean yields. Treatment, formulation and rate per acre Yield cwT/acre Check Temik 15G 2.0 ai/acre Mocap 10G 2.0 ai/acre Mocap 6E 2.0 ai/acre Nemacur 15G 5.0 ai/acre 13.9a 18.4b 16.9ab 16.4ab 18.2b Pratylenchus penetrans at DD10*No. per 100 cm3/soil 890 Pratylenchus penetrans at DD10*No. per 100 cm3/soil 1349 37b 31b 5a 4a 6a 6a 17ab 21b 5a 4a Pratylenchus penetrans at DD10* No. per 100 cm3/soil 368 47a 50a 41a 43a 45a Pratylenchus penetrans at DD10* No. per 100 cm3/soil 1877 Pratylenchus penetrans at DD10* No. per 100 cm3/soil 2167 Pratylenchus penetrans at DD10*No. per 100 cm3/soil Pratylenchus penetrans at DD10*No. per g root tissue 2360 890 Pratylenchus penetrans at DD10* No. per g root tissue 1349 Pratylenchus penetrans at DD10*No. per g root tissue 1877 Pratylenchus penetrans at DD10*No. per g root tissue 2167 Pratylenchus penetrans at DD10*No. per g root tissue 2360 18b 2a la la 1a 55b 9a 7a 10a 14a 80b 31a 28a 36a 21a 41b 2a la 5a 2a 113b 7a 14a 3a 9a 20b 2a la la la 79b 10a 11a 22a 12a 19b 2a 4a 6a la 1 DD10 = accumulated degree days (base 10 C) Column means followed by the same letters are not significantly different according to the Student-Newman-KeuIs Test (P = 0.05) CORN HYBRIDS, PLANT POPULATION AND IRRIGATION E. C. Rossman, B. Darling and K. Dysinger Department of Crop and Soil Science Performance data for 73 commercial corn hybrids evaluated in 1978 with irrigation and without irrigation are presented in Table 1. A total of 8 inches of supplemental water were applied during July and August. Bouyoucous soil moisture blocks were placed at 6, 12, 18 and 24-inch depths in both irri- gated and unirrigated plot areas. Irrigated yields averaged 55.4 bushels more per acre than unirrigated -- 143.6 vs. 88.2, an increase of 63%. Hybrids ranged from 91.5 to 186.0 irrigated and 61.1 to 112.3 bushels per acre without irrigation. Hybrids significantly better than the average yield (arranged in order of increasing grain moisture content at harvest) are listed below. Twenty-one of the 23 hybrids were in the highest yielding group for both irrigated and unirrigated plots. Irrigated Michigan 3102 (2X) ADI 232 (2X) Stanton 10100 (2X) Pioneer 3780 (2X) Pioneer 3901 (2X) Michigan 407-2X (2X) Super Crost 1950 (2X) Funk G-4408 (2X) Blaney B506 (2X) Super Crost 2350 (2X) Amcorn 7480 (2X) Migro M-2018X (2X) Pride 4417 (2X) Pride 4488 (2X) Migro M-2022X (2X) Trojan TXS102 (2X) Funk G-4444 (2X) Migro M-0301 (2X) Acco UC3002 (2X) ADI 315 (2X) Michigan 5912 (2X) Acco UC3301 (2X) ADI 197 (2X) Not Irrigated Michigan 3102 (2X) ADI 232 (2X) Pioneer 3780 (2X) Pioneer 3901 (2X) Michigan 407-2X (2X) Super Crost 1950 (2X) Funk G-4408 (2X) Blaney B506 (2X) Super Crost 2350 (2X) Amcorn 7480 (2X) Migro M-2018X (2X) Pride 4488 (2X) Migro M-015 (2X) Migro M-2022X (2X) Trojan TXS102 (2X) Funk G-4323 (MSX) Funk G-4444 (2X) Migro M-0301 (2X) Acco UC3002 (2X) ADI 315 (2X) Michigan 5912 (2X) Acco UC3301 (2X) ADI 197 (2X) The correlation of irrigated with unirrigated yields was highly significant, .933, indicating that the hybrids tended to respond alike in both situations. During the 11-year period, 1968-1978, the correlations have ranged between .7 and .9 except for 1976 when it was .490. All correlations have been highly significant. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for the 11-year period, 1968-1978, 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 64 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 5.1% irrigated and 2.5% not irrigated, twice as much loding on the irrigated plots in 1978. In 1977, there was also more lodging on the irrigated plots, almost three times more stalk breakage when irrigated. 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 and 1978. Plant Population x Irrigation Five adapted hybrids at four plant populations irrigated and not irrigated were grown in each of 11 years, 1968-1978, Table 3. Over the 11-year period, a population of 23,400 has given the highest average yield (171 bushels per acre) 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 10 of the 11 years. The 11-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 with increased plant population. Bushels per acre 2 year Bushels per acre Bushels per acre Irrig Not 2 years Irrig 3 year Bushels per acre3 years Irrig % Stalk 1978 % Stalk lodging lodging % Stalk lodging % Stalk 2 years lodging Irrig Not 2 years Irrig Not Irrig Irrig 1978 Not Irrig Zone 3 3 years % Stalk lodging % Stalk lodging3 years Irrig Not Irrig Table 1 NORTH CENTRAL MICHIGAN Montcalm County Trial - Irrigated vs. Not Irrigated One, Two, Three Year Averages - 1978, 1977, 1976 Hybrid (Brand - Variety) Michigan 280 (4X) Acco UC1124 (2X) Super Crost 1210 (2X) Pioneer 3975A (Sp.) Michigan 333-3X (3X) Migro M-0101 (2X) Michigan 3093 (3X) Super Crost 1402 (2X) Super Crost 1590 (2X) ADI 195 (2X) Pioneer 3965 (3X) DeKalb XL12 (2X) Pioneer 3958 (2X) Stanton 1090 (2X) Super Crost 31 (4X) Customaize CFS-1000 (2X) DeKalb XL15 (2X) Garno S-84 (2X) Pride 2206 (2X) Super Crost S18 (2X) Jacques JX52 (2X) Super Crost 1692 (2X) Blaney B302-WX (2X) Garno S-90 (2X) *+Michigan 3102 (2X) % Moisture % Moisture % Moisture 2 1978 3 yrs. yrs. 18.5 18.9 19.0 19.1 19.2 22 -- -- -- -- 22 19.3 23 19.4 23 19.8 -- 19.8 -- 19.8 24 -- 23 -- 20.0 -- 20.2 20.2 25 -- 20.6 20.8 -- -- 20.8 -- 20.8 -- 20.8 -- -- 20.9 21.0 25 21.0 -- 21.4 25 -- 21.5 21.5 -- 21.5 25 21 -- -- 21 22 22 -- -- -- 24 -- -- -- -- -- -- -- 24 -- -- 24 Bushels per acre Irrig 1978 Bushels per acre 1978 Not Irrig 91.5 69.0 112.5 71.7 86.1 62.1 138.4 84.8 -- 133.1 88.5 136.0 81.8 123.9 87.2 91.8 61.1 -- 109.5 68.8 107.5 70.5 118.2 80.5 97.1 65.3 -- 124.7 88.9 103.5 66.3 -- 103.6 64.8 129.8 77.4 119.7 73.8 144.8 96.0 149.4 87.3 141.3 83.7 139.2 90.1 123.5 82.3 130.8 80.2 142.4 90.5 180.5 102.0 96 -- -- 121 123 119 -- 98 113 116 -- -- -- -- -- 125 -- 113 -- -- 153 66 -- -- -- 78 76 75 -- -- 63 -- 72 73 -- -- -- -- -- -- 74 -- 75 -- -- 86 108 -- -- -- 129 129 129 -- -- -- -- -- 128 -- -- -- -- -- -- -- 124 -- -- 155 -- -- 63 -- -- -- 78 73 76 -- -- -- -- 73 -- -- -- -- -- -- -- -- 72 -- -- 83 8.9 10.4 4.4 1.5 3.8 5.6 4.2 6.0 2.2 5.0 0.0 10.6 3.8 13.5 3.8 9.9 4.6 3.9 5.6 3.7 6.2 3.8 2.5 0.0 2.6 9.0 9.0 2.4 -- 0.8 3.0 9 -- -- 3 -- -- 6 -- 2 0.0 3.6 2.4 -- 0.8 -- 1.7 1.6 2.5 -- 0.7 4.6 -- 0.8 -- 4.1 -- 3.0 -- 1.5 -- 2.3 -- 2.3 6.8 -- 0.8 0.7 -- 0.0 -- 3.3 8 3 6 0 4 3 2 3 3 3 2 1 1 -- 1 0 2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 8 -- 3 6 3 -- -- 4 -- 2 3 10 -- 2 -- -- 6 5 -- -- -- -- -- 4 -- -- -- -- -- -- -- -- -- -- 3 4 Table 1 Continued Acco UC1151 (2X) Stanton 1095 (2X) Amcorn 4010 (2X) Michigan 3953 (3X) *+ADI 232 (2X) P-A-G SX189 (2X) *Stanton 10100 (2X) *+Pioneer 3780 (2X) Blaney B606 (2X) *+Pioneer 3901 (2X) *+Michigan 407-2X (2X) *+Super Crost 1950 (2X) *+Funk G-4408 (2X) Blaney B406 (2X) *+Blaney B506 (2X) *+Super Crost 2350 (2X) Amcorn 4100 (2X) Michigan 4122 (2X) Funk G-4224 (MSX) Acco UC2301 (2X) *+Amcorn 7480 (2X) *+Migro M-2018X (2X) *Pride 4417 (2X) Michigan 5443 (3X) Funk G-4272 (3X) Amcorn 7300 (2X) Renk RK66 (2X) *+Pride 4488 (2X) Northrup King PX48 (2X) Voris V2372 (2X) Asgrow RX58 (2X) Customaize CFS-115 (2X) +Migro M-0105 (2X) Pickseed XR44 (2X) Super Crost S27 (2X) -- 21.6 21.6 -- 21.8 26 21.8 25 21.8 25 21.8 -- 21.8 -- 21.9 26 21.9 27 22.0 26 -- -- -- -- -- -- -- -- 25 27 22.1 26 -- 22.1 27 -- 22.1 22.3 -- 22.3 26 25 -- -- -- 22.3 26 22.5 26 22.5 26 -- 22.5 22.5 27 22.7 27 22.8 27 23.0 -- 23.0 27 23.0 26 23.1 28 23.1 28 23.1 -- 23.2 27 23.2 27 23.4 27 -- 23.5 23.6 27 23.6 28 23.6 28 25 25 25 -- 26 -- -- -- 26 -- 26 -- -- -- -- 27 -- -- 27 27 151.8 84.0 130.5 76.6 94.0 65.6 84.1 141.5 163.0 99.5 147.3 85.0 159.5 87.3 181.0 104.4 150.3 95.5 164.3 100.5 161.9 102.1 166.6 98.3 186.0 109.4 131.7 78.0 160.9 102.3 185.3 107.6 145.5 88.5 142.4 96.0 139.7 81.1 153.7 89.4 165.4 101.7 181.4 106.5 159.9 87.4 147.1 96.1 147.6 87.5 125.9 80.6 150.9 87.0 161.1 99.3 154.7 89.8 154.9 96.6 149.0 86.6 121.0 72.0 150.7 97.5 141.5 83.6 152.6 94.5 -- -- -- 92 135 140 -- -- 166 136 156 152 -- 161 147 149 132 140 -- 138 148 162 -- 138 132 129 139 149 149 -- -- 147 -- 137 139 141 -- -- 61 77 -- 77 -- -- 96 86 92 -- -- -- 93 98 86 91 81 86 -- -- 78 90 96 -- -- 86 75 -- 79 80 89 89 84 -- 86 82 88 -- -- -- -- -- -- -- 170 148 160 -- -- -- -- 153 141 153 146 -- -- 148 -- 143 -- -- -- -- 155 -- -- 153 154 -- -- -- -- -- -- -- 91 88 89 -- -- -- -- 86 79 87 -- 78 -- -- 84 -- 81 -- -- -- -- 81 -- -- 84 87 8.1 6.9 6.7 4.2 8.7 6.6 3.0 8.8 2.3 0.0 3.0 7.1 2.2 0.8 2.9 4.7 4.4 5.1 8.8 4.8 1.6 0.0 3.9 6.0 7.8 8.0 1.6 1.5 7.5 6.1 4.5 6.4 6.4 9.2 3.1 2.2 -- 2.1 -- 4.4 3.5 6.8 -- 3.1 0.0 -- 2.4 0.8 0.7 1.7 4.6 -- 2.3 0.0 -- 0.8 1.5 0.8 0.9 2.5 -- 6.9 0.0 0.0 1.6 -- 4.1 5.8 5.6 0.8 2.8 -- 2.3 4.5 8.0 1.8 -- 3.9 2.2 2.3 5 4 4 5 2 2 3 2 6 5 5 4 4 1 1 6 7 4 2 7 5 5 10 7 2 -- -- -- -- -- -- -- -- -- -- 2 3 5 1 0 0 1 1 2 1 4 2 5 0 0 3 4 4 0 2 2 4 4 2 2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 5 1 2 -- 4 6 4 3 -- -- 5 -- 3 -- -- -- 5 -- 5 2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 6 1 5 -- 4 7 5 10 -- -- 7 -- 11 -- -- -- -- 8 6 8 Table 1 Continued Pickseed 8858 (2X) *+Migro M-2022X (2X) *+Trojan TXS102 (2X) Michigan 5802 (2X) +Funk G-4323 (MSX) *+Funk G-4444 (2X) *+Migro M-0301 (2X) *+Acco UC3002 (2X) *+ADI 315 (2X) *+Michigan 5912 (2X) *+Acco UC3301 (2X) Customaize CFS-WX120 (2X) *+ADI 197 (2X) Average Range -- 23.7 23.7 28 -- 24.0 24.0 28 24.8 -- 24.8 28 24.9 29 25.3 29 -- 25.4 25.4 29 25.7 30 -- 26.5 -- 29.1 -- -- -- -- 27 27 29 -- -- -- 29 -- -- 122.7 75.1 169.4 101.4 168.3 100.9 153.9 96.2 155.1 100.4 165.3 99.4 164.2 112.3 168.8 97.5 180.0 104.6 168.6 102.8 --- 152 --- 143 --- 148 153 155 --- 163 168.9 101.8 118.7 177.6 98.3 70.4 --- 155 --- 22.2 18.5 to 29.1 26 22 to 30 25 21 to 29 143.6 91.5 to 186.0 88.2 61.1 to 112.3 138 92 to 166 --- 90 --- 88 --- 88 94 90 --- 95 91 --- --- 84 --- --- --- 155 --- 160 160 --- --- --- 161 --- --- 146 61 to 98 108 to 170 --- --- --- 88 --- 85 92 --- --- 87 --- --- 82 --- 63 to 92 Least significant difference 1.2 0.9 0.7 13.9 8.6 8 6 6 5 * Significantly better than average yield, irrigated, 1978 +Significantly better than average yield, not irrigated, 1978 1977 empty table cell April 26 Planted October 28 Harvested Montcalm sandy loam Soil type Corn Previous crop 20,500 Population 30" Rows 283-90-90 Fertilizer 13 Inches Irrigation 6.7 Soil test: pH Soil test:P 391 (very high) 174 (medium) Soil test: K Farm Cooperator: Theron Comden, Montcalm Experimental Farm, Lakeview County Extension Director: James Crosby, Stanton 1978 May 3 November 9 Montcalm sandy loam Corn 20,700 30" 197-60-60 8 inches 6.7 362 (very high) 188 (medium) 3.3 5.0 4.5 4.3 1.5 6.3 8.1 10.8 2.3 2.1 8.0 12.9 0.7 0.9 -- 0.7 5.8 -- 3.0 0.8 -- 0.0 2.2 0.0 0.0 -- 0.0 2.8 4.0 -- 0.0 -- 5.1 2.5 -- -- -- -- -- -- 0 3 0 2 0 0 3 2 -- -- -- -- -- -- -- 4 4 5 -- -- 4 4 -- -- -- -- -- -- -- 7 7 4 -- -- 8 6 4 4 6 5 7 1 5 4 0.0 to 9.0 0.0 0 to to 13.5 6 empty table cell empty table cell empty table cell empty table cell empty table cell empty table cell 1 to 11 0 to 10 1 to 8 1976 May 5 October 29 Montcalm sandy loam Clover 19,300 30" 336-156-156 12 inches 6.7 403 (very high) 163 (medium) Table 2. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for 11 years, 1968-1978. No. of hybrids tested Irrigated Average Average Irrigated Not Highest Irrigated High est Irrigated Not Lowest Irrigated 92 89 120 106 65 78 99 91 95 97 92 93 Lowest Not Irrigated 61 56 49 80 58 73 91 11 70 56 65 61 Year 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 Average 73 74 80 75 76 72 72 56 64 63 56 144 125 156 154 112 114 157 163 144 146 136 Empty table cell 141 88 73 72 125 103 101 137 28 103 86 96 92 186 158 183 207 134 138 206 211 194 185 182 180 112 88 93 157 122 120 179 42 128 109 123 116 Table 3. Average yield at four plant populations irrigated and not irrigated for 11 years, 1968-1978. Irrigated 15,100 15,100 Irrigated Not 19,200 Irrigated 19,200 Irrigated Not Irrigated 23,400 23,400 Irrigated Not Irrigated 27,400 27,400 Irrigated Not 92 74 72 136 100 97 132 37 91 91 114 95 164 152 174 183 130 134 187 189 144 158 169 162 110 81 84 164 111 116 159 35 112 109 130 110 175 160 181 196 135 128 191 191 158 173 193 171 100 70 81 151 98 106 149 20 93 96 107 98 165 150 161 172 120 108 161 181 151 148 178 154 94 69 68 146 94 102 144 11 85 86 89 90 Year 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 146 141 153 158 118 108 152 173 122 126 144 Average 141