1974 Research Report MONTCALM EXPERIMENTAL FARM Michigan State University Agricultural Experiment Station ACKNOWLEDGEMENTS 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. TABLE OF CONTENTS Page INTRODUCTION, WEATHER AND GENERAL MANAGEMENT ..................................................... 1 The Effect of Planting and Harvest Dates on the Production performance of Russet Burbank Seed Potatoes R.W. Chase and R.B. Kitchen........................................................................................... 5 The Effect of Planting Date and Harvest Date on Russet Burbank Yield and Quality R.W. Chase and R.B. Kitchen........................................................................................... 8 Soil Fertility Studies with Potatoes M. L. Vitosh, R.J. Kunze and G. Raines................................................................... 10 Potato Weed Control W.F. Meggitt............................................................................................................................. 14 Use of Row Applications of Soil Fumigants for Control of Root-Lesion Nematode in Potato Production G.W. Bird....................................................................................................................................... 16 Influence of Subsoiling Beneath the Planting Row on Tolerance of Potatoes to Root-Lesion Nematodes G.W. Bird....................................................................................................................................... 18 Use of Temik 10G and Other Granular Nematicides for Control of Root-Lesion Nematodes in Potato Production G.W. Bird .............................................................. 21 Variety Development - Breeding N. R. Thompson............................................................................................................................. 24 Variety Development Program N.R. Thompson and R.W. Chase....................................................................................... 24 Potato Insect Research A. Montcalm Experimental Farm B. Muck Experimental Farm A.L. Wells....................................................................................................................................... 29 Corn Hybrids, Plant Population and Irrigation E.C. Rossman and Barry Darling.................................................................................. 42 MONTCALM BRANCH EXPERIMENT STATION RESEARCH REPORT R. W. Chase, Coordinator 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 eight 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 1974. Much of the data herein reported represents projects in various stages of progress so complete 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 re­ commendations can be made. Weather Temperature and rainfall recordings for the 1974 season are shown in Figure 1. Tables 1 and 2 summarize the 7-year rainfall and temperature data. Average maximum and minimum temperatures for 1974 were similar to those of the 7-year average. For the months of August and September, the 1974 average maxi­ mum was lower than the 7-year average and for each individual year. The average minimum of 45° for September, 1974 was the lowest of any of the seven years. In July there were nine days that the temperature exceeded 85°. The 1974 total rainfall of 23.97 inches for the 6 months period in 1974 was the second highest of 7 years for which records at the Farm are available. One-fourth of the total rain came in August. Rainfall in July and September was less than the 7-year average. Irrigation applications of approximately one inch each were made 7 times (July 10, 15, 22, 27, 30 August 2 and September 7). Soil Tests For specific projects where more detailed analysis are needed the results are in the individual reports. Soil test results for the general plot area are: Pounds per Acre Mg 211 PH Pounds per Acre 6.1 P 395 Pounds per Acre Pounds per Acre Pounds per Acre Ca 1067 K 300 APRIL MAX. 57 MIN. 36 MAY MAX. 62 MIN. 41 JUNE MAX. 73 MIN. 52 JULY MAX. 81 MIN. 57 AUGUST MAX. 77 MIN. 56 SEPT. MAX. 68 MIN. 45 AVERAGE MONTHLY TEMP. RAINFALL 4.07 Inches 4.83 inches 4.69 inches 2.39inches 6.18 inches 1.81 inches Figure 1. Climatology Observations at the Montcalm Experimental Farm in 1974. Table 1. The 7-year summary of recorded maximum and minimum temperatures dur- ing the growing season at the Montcalm Branch Experiment Station. Year 1968 1969 1970 1971 1972 1973 1974 7-year average April April Min Max 61 37 56 35 54 35 53 31 30 47 54 36 36 57 May Max 62 67 65 65 70 63 62 May Min 41 43 47 39 47 42 41 June Max 74 70 72 81 72 77 73 June Min 53 50 55 56 50 58 52 July Max 80 80 80 82 79 79 81 July Min 55 59 60 55 57 60 57 August August Min Max 81 58 56 82 80 57 53 80 57 76 60 80 56 77 September September Max Min 74 50 73 49 70 51 73 54 69 49 73 48 68 45 55 34 65 43 74 53 80 58 79 57 71 49 6 month 6 month average average Min Max 50 73 74 49 45 73 48 76 48 73 74 51 70 48 empty empty cell cell table table Table 2. The 7-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Station. Year 1968 1969 1970 1971 1972 1973 1974 7-year average April 2.84 3.33 2.42 1.59 1.35 3.25 4.07 2.69 May 4.90 3.65 4.09 0.93 1.96 3.91 4.83 June 3.74 6.18 4.62 1.50 2.51 4.34 4.69 July 1.23 2.63 3.67 1.22 3.83 2.36 2.39 3.47 3.94 2.48 August September 1.31 1.79 6.54 2.67 7.28 3.94 6.18 4.24 3.30 0.58 7.18 4.00 2.60 1.33 1.81 2.97 Total 17.32 18.16 28.52 11.91 19.53 19.13 23.97 19.79 Fertilizers Used Except for specific fertility studies where the fertilizers are specified in the report, the following fertilizers were used on the potato plot area: plow down with rye cover crop 0-0-60 150 lbs/A banded with planter 20-10-10 500 lbs/A sidedressed 45-0-0 320 lbs/A Disease and Insect Control A granular systemic insecticide (phorate) was applied at 3 pounds per acre to most of the potato plots at planting. A second application of disulfotan at 3 lb/A was applied to the late maturing varieties at the same time that the 45-0-0 was sidedressed and the crop hilled. The foliar spray program was initiated on June 29 and continued on a weekly basis. All applications were made with an air blast sprayer. The foliar insecticides used were: Endosulfan (Thiodan), Meta-Systox R, Cygon 267 and Monitor. Linuron (Lorox) at 1 1/2 lb/A applied pre-emergence was used for weed control. Bravo and Kocide 101 were used as the fungicides. Des-i-cate at 2 gallons per acre plus a crop oil at 1 gallon per acre was used as the top­ killer. THE EFFECT OF PLANTING AND HARVEST DATES ON THE PRODUCTION PERFORMANCE OF RUSSET BURBANK SEED POTATOES R. W. Chase and R. B. Kitchen Department of Crop and Soil Sciences Procedure Foundation Russet Burbank seed was planted on May 9, 18 and June 1 and harvested on August 15, 30, September 17, and October 1 in 1973. A one- bushel sample was collected from each treatment for storage and subsequent planting in 1974. Before placement in the 40F storage, the samples were stored for approximately 2 weeks at 60-65F and 80-85% relative humidity to allow for proper curing and wound healing. Five days before planting in 1974 the seed was removed from storage and warmed to 50-55F. The seed was planted on May 2, 1974 in one-row plots and six replicates. Except for the treatment of the June 1 planting and August 15 harvest when the tubers did not size, all plantings were made from one seed piece cut from each tuber in the sample. The balance of the tuber was discarded, therefore each plant represented a different tuber. Data on emergence, plant stand, virus disease readings, vigor, yield and quality were obtained. Results and Discussion Table 1 summarizes the yield performance of seed planted and harvested at different intervals. In all cases the total yield is the greatest from seed harvested at the two earlier dates and the lowest yield occurred with the latest harvested seed. Similar response was obtained in 1973, however, the magnitude of reduced yields for the last harvested seed was much greater in 1973. There appears to be no consistent trend in the effect on the per­ cent size distribution and there is no effect on specific gravity. Vigor ratings made early in the growing season relates very closely to the yield results, with the most vigorous and uniform stands producing the greatest yields. The incidence of visual virus leaf roll was the greatest with the late harvested seed indicating that the delay in harvest does in­ crease the hazard of late season leaf roll infections in the seed harvested (Table 2). Aphids were a serious problem in 1973 and this coupled with the high concentration of commercial potato production in the adjacent area re­ sulted in considerable late season virus leaf roll infection. Seed harvested on August 15, 1973 had a zero reading for leaf roll infection in 1974. That harvested on August 30 averaged 3.9%; September 17 averaged 9.9% and the October 1 harvested seed averaged 17.2%. If there is a delay in both the planting date and harvest date then the problem became more serious. The seed planted on June 1 and harvested on October 1, 1973 had leaf roll readings of 26.1% in the 1974 crop whereas the seed planted on May 9 and harvested on October 1, 1973 had leaf roll readings of 11.6%. Of the two factors, har­ vest date seems to have a greater influence on the incidence of late season virus leaf roll infections than does the planting date. Table 1. The total yield, size distribution and specific gravity of Russet Burbank potatoes planted on three different dates and harvest on four different dates. Planting date Harvest date No. days * planting to harvest Total cwt/A ** Percent size distribution Percent size distribution Percent size distribution over 10 oz. off type Percent size distribution 1 7/8 to Specific gravity May 9 May 9 May 9 May 9 May 18 May 18 May 18 May 18 Aug. 15 Aug. 30 Sept. 17 Oct. 1 Aug. 15 Aug. 30 Sept. 17 Oct. 1 Aug. 15 Aug. 30 Sept. 17 Oct. 1 98 113 131 145 89 104 122 136 76 91 109 123 less than 1 7/8 9.3 12.2 8.8 10.7 12.8 13.0 8.6 9.5 9.8 11.6 10.2 9.5 368 397 331 344 392 373 364 334 369 381 345 322 13.5 13.2 20.1 18.3 11.1 13.5 19.7 14.8 12.7 14.9 19.9 17.2 6.5 5.9 12.8 10.7 7.4 7.0 8.1 14.7 9.1 10.6 6.0 16.7 70.7 68.7 58.3 60.3 68.7 66.5 63.6 61.0 68.4 62.9 63.9 56.6 1.079 1.079 1.077 1.077 1.080 1.079 1.079 1.080 1.079 1.079 1.078 1.079 June 1 June 1 June 1 June 1 * Dates are for seed grown in 1973. ** Yields, percent size distribution and specific gravity are from 1974 harvests. Table 2. The incidence of visual leaf roll symptoms in 1974 plantings from Russet Burbank seed planted and harvested at different times in 1973. Planting date May 9 May 9 May 9 May 9 May 18 May 18 May 18 May 18 June 1 June 1 June 1 June 1 Harvest date Aug. 15 Aug. 30 Sept. 17 Oct. 1 Aug. 15 Aug. 30 Sept. 17 Oct. 1 Aug. 15 Aug. 30 Sept. 17 Oct. 1 Percent of plants showing visual virus leaf roll symptoms 0 5.1 7.3 11.6 0 4.4 3.6 13.8 0 2.2 18.8 26.1 Table 3 summarizes the yield performance of seed planted on three different dates disregarding the harvest date. In 1974 there was no yield or quality difference whereas in 1973 the yield difference between the earliest and latest planted seed was 43 cwt per acre in favor of the earlier planting. When one evaluates the harvest date only and disregards the planting date, Table 4, then there is a general decline in the yield performance as the harvest date is de­ layed. Similar resuts did occur in 1973. The increased incidence of virus leaf roll infection with the late harvested seed is a factor here also. Based on these two years data and observations it does appear that produc­ tion management does have an influence on subsequent seed performance. Earlier harvested seed does result in a more uniform and vigorous crop growth the following year with resulting higher yields and the incidence of late season virus leaf roll spread is lessened. Table 3. The total yield, specific gravity and size distribution of Russet Burbank potatoes grown from seed planted at 3 different times. Percent size Percent size distribution Percent size distribution Planting * date May 9 May 18 June 1 * Planting dates are for the seed grown the previous year. distribution 10 oz. 16.1 14.7 16.1 Off type 8.8 9.2 10.4 Percent size distribution Less than 1 7/8 10.3 11.1 10.3 1974 Total cwt/A 360 365 354 1 7/8- 10 oz. 64.8 65.0 63.2 Specific gravity 1.078 1.079 1.078 Table 4. The total yield, specific gravity and size distribution of Russet Burbank potatoes grown from seed harvested at 4 different times. Harvest * date 1974 Total cwt/A Percent size distribution Percent size distribution Percent size distribution Less than 1 7/8 Over 10 oz. Off type Percent size distribution 1 7/8- 10 oz. August 15 August 30 September 17 October 1 * Harvest dates are for the seed grown the previous year. 10.7 12.3 9.2 9.9 7.7 7.8 8.9 14.0 12.4 13.9 19.9 16.8 376 383 346 333 69.2 66.0 62.0 59.3 Specific gravity 1.079 1.079 1.078 1.078 THE EFFECT OF PLANTING DATE AND HARVEST DATE ON RUSSET BURBANK YIELD AND QUALITY R. W. Chase and R. B. Kitchen Department of Crop and Soil Sciences Procedure New Foundation seed of the Russet Burbank variety was planted on three different planting dates and harvested on four different dates in 1972, 1973 and 1974. The seed planted was predominantly whole seed, however when necessary the larger size tubers were split before planting. The seed was planted with a commercial two row picker-planter and recommended cultural practices of fertilization, irrigation, insect, disease and weed control were followed. On four different dates, three-two row plots were harvested from each of the three plantings. Yields, size distribution and specific gravity readings were determined. No topkiller was used and the vines were allowed to continue to grow until harvested. Planting dates and harvest dates for each of the three years are summarized as follows. empty cell table Planting dates: early: intermediate: Planting dates: late: Planting dates: 1. 2. Harvest dates: 3. Harvest dates: Harvest dates: 4. Harvest dates: 1972 May 9 May 18 May 31 Aug. 15 Sept. 1 Sept. 15 Oct. 4 1973 May 9 May 18 June 1 Aug. 15 Aug. 30 Sept. 18 Oct. 1 1974 May 2 May 20 June 4 Aug. 16 Sept. 3 Sept. 17 Oct. 2 Results and Discussion Table 1 summarizes the total yield data for each year and the combined 3 years. As expected, the greatest yields did occur with the earliest plant­ ing. The difference between the early and intermediate average yields is only 24 cwt/acre; however, the difference in yields between the early and late planting of 109 cwt/acre and the 85 cwt/acre difference between the intermediate and late is much more substantial. One interesting observation is that even though the top growth was still green and actively growing, for both the early and intermediate plantings, there was no increased yield obtained from delaying harvest from mid-September to early October. Even with the late planting where there was a yield in­ crease between harvests 3 and 4, the difference is only 18 cwt/acre and this is not significant. September 22 and 23 of 1974 with low recorded temperatures of 29F and 25F, respectively were the only times during the 3 years of the study that the September temperature went below freezing and this was not sufficient to completely kill all top growth. Active, green top growth was still visible on the last harvest date in 1974. Table 1. The total yield (cwt/A) of Russet Burbank planted at 3 different times and harvested on 4 different dates (1972-1974). Planting time: Harvest time: Year 1972 1973 Year 1974 Year 3-year average early 1 289 217 250 252 earlyearly 2 3 earlyIntermediate IntermediateIntermediate Intermediate late 4 1 2 3 4 1 late late 3 4 late 2 335 281 337 318 376 329 399 368 368 303 389 356 244 169 230 214 313 252 315 293 365 294 375 345 370 287 371 343 97 114 92 101 169 226 186 194 277 291 248 272 289 292 288 290 The daily growth rate expressed as cwt/A/day is greater during the two- week interval between harvests 1 and 2 than it is between harvests 3 and 4. The rate of growth is most rapid with the later planted lots, however the re­ sulting final yield is the lowest. The average daily growth rate for the early and intermediate planting is 5.2 cwt/A/day from mid-August to early-September and 3.6 cwt/A/day from early-September to mid-September. The average daily growth for the late planting is 6.6 cwt/A/day from mid-August to early-September and drops to 5.6 cwt/A/day from early to mid-September. Table 2 summarized the data obtained for specific gravity readings. Again it is interesting to note that specific gravity readings increased with the later harvests however there was a marked decrease each year between mid-September and early-October regardless of the planting date. The only two exceptions to this trend were in 1974 when for the intermediate planting the specific gravity remained the same between harvests 3 and 4 and with the late planting it actually increased from 1.077 to 1.082 between harvests 3 and 4. Table 2. The specific gravity of Russet Burbank planted at 3 different times and harvested on 4 different dates (1972-74). early early Intermediate Late Late early early IntermediateIntermediateIntermediate Late Late Planting time Harvest time Year 1972 Year 1973 1974 Year 3-year average 1 2 3 4 1 2 3 4 1 2 3 4 1.074 1.075 1.076 1.073 1.075 1.076 1.079 1.073 1.065 1.070 1.077 1.073 1.076 1.087 1.084 1.083 1.075 1.086 1.083 1.079 1.070 1.082 1.082 1.079 1.081 1.082 1.085 1.082 1.078 1.080 1.084 1.084 1.070 1.074 1.077 1.082 1.077 1.081 1.082 1.079 1.076 1.081 1.082 1.079 1.068 1.075 1.079 1.078 The effect of planting dates and harvest dates on percent size distribu­ tion is not as pronounced or consistent. In general, the later planted crop will produce a greater percentage of tubers under 1 7/8 inches and tubers over 10 ounces are much less as one would expect. Also, the mid-August harvest, regardless of planting date, produces a much higher percentage of B size tubers than the later harvests. For both the early and intermediate planting dates, the percentage of B size tubers at 10-14% was established by the early September harvest and remained in this range for the subsequent har­ vests. The maximum percent of tubers over 10 ounces reached its peak by the mid-September harvest. For the late planted crop there was about a two-week lag in the growth patterns. The results observed in this study suggest that in terms of yield and specific gravity there is no value in delaying harvest beyond mid-September. The risk and hazard of damage from cold weather also becomes greater as the harvest is delayed. It further suggests that by mid-September the potato crop has reached its greatest yield and quality. SOIL FERTILITY STUDIES WITH POTATOES M. L. Vitosh, R. J. Kunze and G. Raines Department of Crop and Soil Sciences In 1924, two soil fertility experiments were conducted. One was a liming study to evaluate the effect of lime on potato yield, quality and incidence of scab disease. This study was a follow-up to several previous studies where yields were positively correlated with soil pH. The second study was a time of nitrogen application study first initiated in 1972. Nitrogen fertilizer applied through the irrigation system and spaced throughout the growing season was compared with nitrogen applied as a side­ dress application. Lime Study This experiment included 3 lime rates (0, 2 and 4 tons/acre) and 2 liming materials (dolomitic agriculture limestone, Dry and Moist). The dry bin-storage lime had a moisture content of zero while the moisturized stockpiled lime had 14% moisture. Both materials had a neutralizing value of 106. The actual amount of lime applied was adjusted according to neutralizing value and moisture so that treatments 2 and 3 received an equivalent amount of lime based on a neutra­ lizing value of 100 (pure calcium carbonate) as treatments 4 and 5. This was done so that each material would neutralize approximately the same amount of acidity. If applied strictly on a weight basis the dry lime would have neutra­ lized considerably more acidity. The results of the study are shown in Table 1. The cultural and management practices are listed at the bottom of the table. Potato tubers were sized into three categories (those greater than 3 1/4 inches, those less than 1 7/8 inches and those between 1 7/8 and 3 1/4 inches). Specific gravity of tubers was deter­ mined by the hydrometer method at East Lansing shortly after harvest. Scab ratings were made in the field at the time of harvest by rating from 0 to 10. Those receiving 0 - rating had no evidence of scab while a rating of 10 would be a tuber with the entire surface covered with scab. Table 1. Effect or rate and source of lime on yield, size and specific gravity or irrigated Kennebec and Katahdin potatoes. Kennebec Kennebec Katahdin Katahdin Lime treatmentsa Kennebec Total yield Kennebec Over 3 1/4"% 1 7/8" to 3 1/4" less than 1 7/8"% SP Kennebec GR Scab Kennebec rating Katahdin Total yield Katahdin Over 3 1/4"% 1 7/8" to 3 1/4" less than 1 7/8"% SP Katahdin GR Scab Katahdin rating No lime 2 Ton Dol-Ag Lime (dry) 4 Ton Dol-Ag Lime (dry) 2 Ton Dol-Ag Lime (moist) 4 Ton Dol-Ag Lime (moist) LSD (.05) cwt/A 273 289 250 233 276 NS 13 10 9 9 10 NS % 73 77 75 75 75 NS 8 9 10 10 9 2 1.065 1.066 1.066 1.064 1.066 NS % 5 10 10 10 8 NS cwt/A 294 263 276 254 301 NS 14 10 13 13 14 NS % 76 78 75 77 77 NS 11 12 12 10 9 2 1.067 1.065 1.068 1.068 1.068 NS % 15 10 15 15 12 NS a Lime was applied on an equivalent basis using a neutralizing value of 100 for pure calcium carbonate. Planted: May 7, 1974 Row spacing: 32 inches Basic fertilizer: 500 lbs. 20-10-10 at planting Seed spacing: 10 inches Irrigation: 7 inches Harvested: October 3, 1974 Harvest area: 266 sq. ft. Soil tests: pH = 6.0, P = 230, K = 302, Ca = 939, Mg = 126 Table 2. Effect of time of nitrogen application on yield, size and specific gravity of Kennebec and Russet Burbank potatoes. Kennebec Kennebec Russet Burbank Nitrogena applications Kennebec Total yield Kennebec Over 3 1/4" % 1 7/8" to 3 1/4" % less than 1 7/8"% Kennebec Specific gravity Russet Burbank Total Russet Burbank Over 1 7/8" 10 oz % yield to 10 oz Russet Burbank less than 1 7/8"% Russet Burbank Off Russet Burbank Specific gravity type % 100 PT, 120 ESD 100 PT, 60 ESD, 3*20 Irr. 100 PT, 6*20 Irr. LSD (.05) cwt/A 418 . 468 466 NS 13 11 17 NS 78 81 76 NS 9 8 6 NS 1.070 1.072 1.072 NS cwt/A 358 386 385 NS 12 13 13 NS % 68 71 72 NS 13 12 11 NS 7 4 4 NS 1.079 1.077 1.079 NS aPT = planting time, 5/13/74, ESD = Early sidedress, 6/24/74 3*20 Irr. = three bi-weekly applications of 20 lb N/A; 6*20 = six weekly applications of 20 lb N/A through the irrigation system. Planted: May 13, 1974 Row spacing: 34 inches Basic fertilizer: 500 lbs 20-10-10 at planting Irrigation; 7 inches Seed spacing: 12 inches Harvested: October 10, 1974 Harvest area: 283 sq. ft. The two varieties, Kennebec and Katahdin, were not significantly affected by any of the treatments. Scab ratings were very low with average ratings of less than 1 (less than 10%). These varieties were selected because of their susceptibility to scab disease. Many growers are afraid to lime because they fear that liming may cause scab. This study does not substantiate their fears. Yield and specific gravity likewise were uneffected by liming. Time of N Application Study Nitrogen fertilizer was applied to obtain 3 comparable treatments, all receiving the same amount but at various times of application throughout the growing season. All treatments received 100 lbs N/A as a starter fertilizer. The first treatment received 120 lbs N/A in one sidedress N on June 24 and another 20 lbs N/A biweekly through the irrigation system for the next 6 weeks. The third treatment received 20 lbs N/A on a weekly schedule through the irri­ gation system over a 6-week period. Neither yield nor specific gravity were significantly affected by the nitrogen treatments (Table 2). Both varieties, however, tended to yield better where N was applied through the irrigation system. The three-year average (Table 3) would indicate : that N through the irrigation system in either weekly or biweekly intervals has a 30 to 40 hundredweight advantage over the conven­ tional method of sidedress application. Table 3. Three year average for total yield and specific gravity of Kennebec and Russet Burbank varieties as affected by nitrogen applied through the irrigation system (1972-74). Nitrogena applications PT + ESD PT + ESD + 3 Irr. PT + 6 Irr. Kennebec Kennebec Total yield 399 454 451 Specific gravity 1.071 1.073 1.072 Russet Burbank Russet Burbank Specific Total gravity yield 1.075 354 1.073 381 1.074 390 Overall Average Overall Average Total yield 376 418 420 Specific gravity 1.073 1.073 1.073 (a) PT = Planting time N, ESD = Early sidedress N 3 Irr. = 3 biweekly applications in irrigation water 6 Irr. = 6 weekly application in irrigation water Nitrogen rates varied slightly from year to year, however, the total amount applied each year was between 220 and 240 lbs N/Acre for each treatment. POTATO WEED CONTROL William F. Meggitt Dept. of Crop & Soil Science Preemergence and Postemergence Weed Control Evaluations in Potatoes Montcalm County, Michigan 1974. Herbicide applications on potatoes in 1974 indicated excellent control of broadleaved and annual grass weeds. Sencor (metribuzin) delayed preemergence or postemergence provided complete control. In this program it is possible to use Sencor preemergence and follow with a postemergence application if necessary. Lorox & Lasso and Sencor & Lasso add a new possibility of controlling weeds that have emerged prior to a delayed preemergence treatment and also providing extended control especially of barnyard grass which is becoming more of a problem. Two new materials Gulf S-6044 and Ortho 17111 offer promise for furture development in potato weed control. At present there are no registrations for use of Sencor, Sencor & Lasso or Lorox & Lasso in potatoes. Preemergence and Postemergence Weed Control Evaluations in Potatoes Montcalm County, Michigan 1974. Planted: May 2, 1974 Treated: Pre May 29, 1974 Post June 27, 1974 Variety: Soil Type: Sandy Clay Loam Organic Matter: 2.4% Burbanks Weeds Present: Pigweed, Barnyard Grass Tmt. No. Pre Treatments Treatments Post lbs/A Injury Weed Control Ratings PW Weed Control Ratings BG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Sencor Sencor Sencor + — Sencor+Lasso DNBP+Lasso Lorox+Lasso Maloran+Lasso S-6044 S-6044 Probe Probe+Lasso Ortho 17111 Ortho 17111 - _ — — Ortho 16973 Ortho 16973 Lorox No Treatment - 1/2 1 1/2+1/2 1/2 1/2+2 4 1/2+2 1+2 1 1/4+2 2 4 2 1/2+2 1 2 1 2 2 1 — 1 1/2 — Sencor Sencor — - — - — — — — — - Ortho 17111 Ortho 17111 — — - — 0.0 0.7 0.0 0.0 0.1 0.2 2.7 2.7 0.0 0.0 3.3 3.0 0.3 1.3 0.7 2.3 1.7 1.0 2.7 0.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 9.7 10.0 10.0 10.0 8.7 10.0 10.0 9.7 10.0 0.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 9.3 10.0 10.0 10.0 5.7 9.3 9.7 9.7 10.0 0.0 0 = No control and no injury; 10 = complete control or kill. USE OF ROW APPLICATIONS OF SOIL FUMIGANTS FOR CONTROL OF ROOT-LESION NEMATODE IN POTATO PRODUCTION G. W. Bird Department of Entomology Plant parasitic nematodes cause approximately 10% or four million dollars in annual losses in Michigan potato production. Most of this damage is caused by the root-lesion nematode (Pratylenchus penetrans). Fall appli­ cations of broadcast rates of soil fumigants are recommended for the control of plant parasitic nematodes in potato fields. Chemical costs are in excess of $40.00 per acre and will only control nematodes for a single growing season. Row applications of soil fumigants are not presently recommended for potato production in Michigan, but would decrease both the cost and amount of chemical used by 60%. The objective of this investigation was to determine the efficacy and feasibility of the use of row applications of soil fumigants for control of root-lesion nematode in potato production in Michigan. Two registered fumigant nematicides and two experimental granular nematicides were evaluated (Table 1) in this experiment at the Montcalm Experimental Farm (M.S.U.). Each treatment was replicated four times in a randomized block design, containing plots 11 ft 4 inches wide and 50 ft in length. Broadcast applications of Vorlex and Terr-o-cide 15D were injected to a depth of 6-8 inches, and row applications were made by injecting one- half of the fumigant at a 6-inch depth and the other half at an 18-inch depth. All soil fumigants were applied on April 26, 1974. On May 20, all plots were planted with four 34-inch rows of Russet. Burbank potatoes. Granular nematicides were applied at planting and incorporated to a 2-4 inch depth. The plots were maintained under commercial fertility, weed, insect and disease control pro­ grams, and irrigated when necessary. Plant growth data and nematode population dynamics determinations were made at several intervals throughout the growing Table 1. Influence of broadcast and row applications of soil fumigants and granular nematicides on (Pratylenchus penetrans) and yield of Russet Burbank potatoes, Montcalm, Michigan, 1974. Treatment. method of application -and rate per acre (active) Pratylenchus penetrans per g root (7/16/74) Total yield (ctw per acre) Check (no treatment) Terr-o-cide 15D (10.0 gal, broadcast) Terr-o-cide 15D (4.0 gal, row) Vorlex (30.0 gal, broadcast) Vorlex (10.0 gal, broadcast) Vorlex (4.0 gal, row) Nemacur 15G (4.0 lb, 8-inch band) Furadan 10G (3.0 lb. 8-inch band) 25 a 1 15 ab 13 ab 2 b 8 b 6 b 3 b 13 ab 380 a 437 b 439 b 431 b 467 b 451 b 420 b 427 b 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test. season. The tubers were harvested and graded on October 9, 1974. All treatments appeared to retard population development of root-lesion nematodes (Table 1). The three treatments with Vorlex and the granular application of Nemacur gave the best nematode control. All treatments re­ sulted in significant increases in yield. The treatments had no influence on potato grade. The data demonstrate that row applications of soil fumigants can be used in Michigan for the control of root-lesion nematodes. It is highly probable that a slightly greater rate of Terr-o-cide 15D would have resulted in a significantly greater suppression of root-lesion nematodes. It should be remembered that Russet Burbank potatoes are significantly less susceptible to root-lesion nematode damage than most of the cultivars grown in Michigan. Based on the present investigation, the Michigan Cooperative Extension Service will recommend row application of soil fumigants for control of root­ lesion nematodes in potato production in 1975. INFLUENCE OF SUBSOILINC- BENEATH THE PLANTING ROW ON TOLERANCE OF POTATOES TO ROOT-LESION NEMATODES G. W. Bird Department of Entomology Soil compaction can directly inhibit normal growth, development and yield of many economically important plants. Soil compaction can also in­ directly cause crop plants to be more susceptible to damage caused by para­ sitic nematodes. Recently several commercial agricultural equipment com­ panies have developed equipment for subsoiling immediately beneath the planting row. This type of land preparation has been shown to alleviate both the direct and indirect detrimental influences of soil compaction on crop growth and yields. The objective of this investigation was to determine the influence of subsoiling beneath the planting row on population dynamics of root-lesion nematodes and on the growth, development and yields of potatoes. Subsoiling beneath the planting row was evaluated at the Montcalm Experimental Farm (M.S.U.). The treatments (Table 2) were replicated five times in a randomized block design, containing plots 11 ft 4 inches wide and 50 ft in length. Half of the plots were subsoiled beneath the planting row and bedded on April 26, 1974. They were planted on May 20, with four 34-inch rows of Russet Burbank potatoes. The plots were maintained under commercial fertility, weed, insect and disease control programs, and irrigated when necessary. Growth data and nematode population dynamics determinations were made at several intervals throughout the growing season. The tubers were harvested and graded on October 8. Subsoiling beneath the planting row significantly increased yields of cv Russet Burbank potatoes (Table 2). It had no influence on tuber grade or nematode population dynamics. This change in growth and development patterns of the plant was detected as early as 30 days after planting. It is highly probable that subsoiling beneath planting furrow increased the tolerance limit of Russet Burbank in relation to the root-lesion nematode. The yield increase obtained with this treatment is similar to that obtained by controlling root-lesion nematodes with soil fumigants. It should be remembered that Russet Burbank potatoes are significantly less susceptible to root-lesion nematode damage than most of the other cultivars grown in Michigan. Table. 2. Influence of subsoiling beneath the planting row on the growth and development of Russet Burbank potatoes and recoverable populations of Pratylenchus penetrans. Potato growth and nematode population density parameters Commercial soil preparation Subsoiling beneath the planting row Early season potato growth data (6/27/74) Early season potato growth data (6/27/74) Early season potato growth data (6/27/74) Root weight (g) per plant Tuber weight (g) Tubers per plant Mid-season potato growth data (7/19/74) Root weight (g) per plant Tuber weight Tubers per plant Yield (ctw/acre, 10/8/74) Total tuber weight 10 oz tubers A tubers B tubers Knobby tubers Pratylenchus penetrans per g root tissue 6/27/74 7/19/74 12 A1 0.4 C 3 E 400 I 94 K 240 L 23 M 45 N 22 B 1.6 D 7 E 440 J 89 K 263 L 29 M 63 N Mid-season potato growth data (7/19/74) Mid-season potato growth data (7/19/74) 51 F 12 G 13 H Yield (ctw/acre, 10/8/74) 54 F 11 G 17 H Yield (ctw/acre, 10/8/74) Pratylenchus penetrans per g root tissue Pratylenchus penetrans per g root tissue 23 Ø 79 P 11 Ø 61 P 1Comparable row means followed by the same letter are not significantly different (P=0.05 according to the Student-Newman-Kuels Multiple Range Test. USE OF TEMIK 10G AND OTHER GRANULAR NEMATICIDES FOR CONTROL OF ROOT-LESION NEMATODES IN POTATO PRODUCTION G. W. Bird Department of Entomology Until the spring of 1974, only fumigant nematicides were registered for use on land to be planted with potatoes. On April 17, 1974, Temik 10G was registered by E.P.A. for control of root-lesion and root-knot nematodes in potato fields. Unfortunately, however, the date of this registration was too late to benefit Michigan potato growers during 1974. Temik 10G is regis­ tered for nematode control at a rate of 30.0 lb per acre, and for insect control at 20.0 to 30.0 lb per acre. The objects of the present investiga­ tion were to determine the nematicidal efficacy of Temik at an insecticide rate, compared with experimental granular nematicides. Eleven granular nematicide treatments (Table 3) were evaluated for control of root-lesion nematodes at the Sodus Vegetable Experimental Farm (M.S.U.). Each treatment was replicated five times in a randomized split block design containing plots 5-ft wide and 25 ft in length. Each plot was completely surrounded by a 5-ft border area. The plots were planted on May 1, 1974, with 30-inch rows of Russet Burbank potatoes. All nematicide applications were made at planting. The banded and post-plant side-dress materials were incorporated to a depth of 2 inches, and the in-furrow applications were placed in the planting furrow. The plots were maintained under commercial fertility, weed, insect and disease control programs, and irrigated when necessary. Plant growth data and nematode population dynamics determinations were made at various intervals throughout the growing season. The tubers were harvested and graded on October 18, 1974. Table 3. Influence of Temik 10G and experimental granular nematicides on root-lesion nematodes and yield of Russet Burbank potatoes (Sodus, Michigan, 1374). Treatment, method of application and lb per acre (active) Pratylenchus penetrans per Pratylenchus penetrans per g root tissue g root tissue Total Yield (ctw per acre, 10/18/74) Check (non-treated) SD 8332 10G (1.0, 8-inch band) SD 8332 10G (2.5, 8-inch band) SD 8332 10G (4.0, 8-inch band) SD 8332 10G (5.0, 8-inch band) CGA 1223 10G (3.0, 8-inch band) CGA 1223 10G (1.5 + 1.5, UC 21865 50OWP (2.0, in-furrow) Temik 10G (2.0, in-furrow) Vydate 10G (4.0, 8-inch band) Nemacur 15G (4.0, 8-inch band) Furadan 10G (4.0, 8-inch band) 8-inch band + side dress) 7/1/74 56.2 a1 7.6 b 63.8 a 4.6 b 28.0 a 1.4 b 1.2 b 60.2 a 2.6 b 36.6 ab 2.4 b 6.8 b 9/6/74 137.2 ab 202.4 ab 148.8 ab 117.2 ab 185.6 ab 24.8 b 12.0 b 422.8 a 94.4 ab 285.6 ab 50.0 b 32.0 b 272 a 302 a 298 a 321 a 306 a 314 a 251 a 321 a 310 a 312 a 353 a 348 a 1Column means followed by the same letter are not significantly different (P=0.05) according to the Student-Newman-Keuls Multiple Range Test. While CGA 1223, Temik, Nemacur, Furadan and two rates of SD 8332 Significantly suppressed early-season population development of root-lesion nematodes, only CGA 1223, Nemacur and Furadan reduced populations to a low enough level to maintain control through most of the growing season (Table 3). Although there were no significant yield differences among the various treatments, higher yields were generally associated with successful root­ lesion nematode control. It should also be noted that Russet Burbanks are less susceptible to root-lesion nematode damage than most potato cultivars grown in Michigan. While a limited amount of early-season root-lesion nematode control was obtained with the lowest registered insecticidal rate of Temik, population suppression at this rate was not as good as more appropriate rates of other comparable experimental nematicides. It must be concluded, that if an initial root-lesion nematode population is above the tolerance limit for the potato cultivar used, and if Temik is chosen for nematode control, it is essential that the registered nematicidal rate be applied. When used pro­ perly, Temik is an excellent nematicide, and it will be recommended in 1975 by the Michigan State University Cooperative Extension Service for control of root-lesion nematodes in Michigan potato production. VARIETY DEVELOPMENT - BREEDING N. R. Thompson Department of Crop and Soil Sciences One hundred and four advanced selections from 1970 crosses were grown at both the Montcalm Experimental Farm and Foundation Seed Farm, E. Lansing. Thirty-two of these were discarded because of lack of yield tuber shape or disease. Of the remaining 72 nineteen have been selected for consistent yield, high solids and good culinary qualities. Ten cultivars with high yield and consistent processing qualities will be increased as rapidly as possible. Two of these have yellow flesh. From 1971 crosses 12 outstanding selections were made from the 32 cultivars planted. These require an additional year of testing to determine consistency. Forty-eight selections based on yield and type were made from 1972 crosses. Two thousand seedlings from 1973 crosses were grown in the greenhouse to be planted in the field in 1975. All cultivars planted at the Foundation Seed Farm, East Lansing were harvested as hills and one tuber from each is being grown in the Florida test. Increase proposals will be dependant upon Florida readings. VARIETY DEVELOPMENT PROGRAM N. R. Thompson and R. W. Chase Department of Crop and Soil Sciences Good new potato varieties have been released in the past few years. Some of these appear well adapted to Michigan. While the single all purpose variety is not at hand, at least one of those tested should provide an additional choice for fresh pack, frozen processing, chips. A. Overstate Variety Trials. Seventeen varieties or numbered cultivars were grown in six locations. The overall average yields are given in table 1. The detailed data for yields, specific gravity, chip color and after cooking darkening for the Montcalm location are shown in Table 2. The consistent high yield of the Hudson variety will be appreciated by producers of fresh pack potatoes. This variety released for resistance to the golden nematode produces bright, white skinned potatoes with medium total solids. The tubers tend to be large as evidenced by the high percentage of marketable tubers. However, cultural practices such as spacing, fertilization and supplemental irrigation may have to be adjusted to produce the most desirable size for market demands. The acceptance of Nampa and Targhee will be dependent upon processor demand. While both yield well and have high solids contents, Nampa has exhibited shape problems and Targhee is subject to air checks and after cooking darkening. For the potato chip industry, Wischip and the three N. Dakota entries all showed good reversion resistance when held at 58 F. Wischip yields were lower than anticipated and the foliage showed severe speckle leaf damage. This variety has performed better in previous trials when tested as Wise. 629. The red cultivar, ND 6634-2R, looks promising as few reds are consistent chippers and has now been officially released as Bison. The two M.S.U. entries are in the seed increase program. MS 503 is a good general purpose potato. It consistently cooks white and can be recon­ ditioned for chips. Yields of MS 709 were below normal. Seed quality is important to any crop and the quality of available seed of MS 709 was questionable. Its potential has been established in past trials. B. Seed Increase 1. Foundation Seed Farm, East Lansing. For the past two years, the Michigan Foundation Seed Association has made available an acre of irrigated land south of their headquarters on Jolly Rd. This is used for hill increase and tuber units from greenhouse or southern tested cultivars in the breeding program. The proximity to the University permits intensive screening for disease symptoms throughout the growing season. One-half acre was treated by Dr. G. Bird with Vorlex for 1975 plantings to attempt to eliminate problems that could confuse disease expressions. 2. Lennard Farms-Newberry. A three acre plot isolated from other potatoes provided ideal increase for several promising seedling from the breeding program. 1111-2 - One acre of clonal increase plus hills which passed the southern test. This is the earliest maturing cultivar in the program. The tubers are white and smooth. It makes an attractive fresh pack. While chip color is good from the field it does not recondition. Table 1. The overall average yield (U.S. No. 1 cwt/A) of seventeen potato varieties grown at six locations. Variety Hudson Nampa Targhee Onaway Katahdin MS 503 R. Burbank Shurchip W 623 Hi Plains Rushmore MS 709 ND 6634-2B Norchip ND 7196-18 Wischip ND 7878-1 Ave. Montcalm Bay Emmet VanBuren Presque Isle Allegan Ave. 525 423 466 406 378 437 345 273 398 293 283 384 267 207 316 177 123 335 497 322 318 443 361 371 386 343 355 337 349 365 240 368 244 216 275 341 455 393 276 328 395 296 330 229 239 283 304 263 198 255 255 159 177 284 591 517 482 460 458 433 505 450 417 431 365 374 429 367 341 306 197 420 511 417 345 415 427 386 294 400 328 333 359 328 377 287 306 310 245 357 550 417 503 325 316 335 364 339 278 328 335 218 252 238 205 230 104 314 522 415 398 396 389 376 371 339 336 334 333 322 294 287 278 233 187 342 Table 2. The yield, specific gravity, chip rating and after cooking darkening of several potato varieties grown at the Montcalm Exp. Farm in 1974.* Yield Total (cwt/A) Yield Marketable (cwt/A) Yield % Marketable Specific Gravity Chip color* ** (11/18) After Cooking Color *** After Cooking Color 24 hrs. 0 hr. *** After Cooking Color *** 1 hr. 540 509 456 454 440 468 418 427 427 404 335 317 320 326 265 264 525 466 437 423 406 398 384 378 345 316 293 283 273 267 207 177 97 92 96 93 92 85 92 86 81 78 87 89 85 85 78 67 1.074 1.091 1.079 1.088 1.065 1.079 1.070 1.072 1.085 1.072 1.074 1.066 1.068 1.065 1.075 1.073 193 386 123 335 64 87 1.077 1.075 7 6 4 5 7 3 5 3 5 2 3 2 3 2 2 2 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 3 1 1 2 1 1 2 2 2 2 2 2 2 2 1 1 5 1 1 2 1 1 3 2 2 2 3 2 2 2 1 2 1 2 2 Empty Table Cell Empty Table Cell Empty Table Cell Empty Table Cell Variety Hudson larghee MS 503 lampa Onaway Wis 623 MS 709 atahdin Burbank D 7196-18 li-Plains Rushmore hurchip D 6634-2R orchip ischip D 7878-1 Ave. * Planted May 7 and harvested September 11, 1974 ** Based on 1 to 10 scale. 1 = lightest and 10 = darkest chip color. ** Based on 1 to 5 scale. 1 - white with no darkening and 5 severe darkening throughout tuber. 711-8 - hill increase - a high yielding smooth white potato for fresh pack. it does not chip. 645-1 - hill increase - the tubers are slightly rough but has rated high in chip tests. 645-2 - hill increase - a high yielding mid-season large smooth tuber which chips at harvest. 706-32 - hill increase - one of our highest yielding seedlings. The tubers are slightly irregular in shape. Fresh pack only. All seedlings grown on the Lennard farms have been released to the Foundation Seed Association. Increases will depend upon Florida readings. 3. Brasington Farms - Edmore One acre of hill increase MS 709 was planted for possible seed use. Growth was vigorous but a mild mottle in some plants was too widespread to make rogueing practical. The plot was abandoned to commercial pro­ duction. POTATO INSECT RESEARCH Arthur L. Wells Department of Entomology The 1974 entomological research on potatoes was aimed at better under­ standing the effects of insect control programs on seed production as well as the evaluation of new soil systemic and foliar insecticides. A. Evaluation of Production Techniques on Seed Qaulity at the Montcalm Experimental Farm The green peach aphid continues to be the prime target for most control programs on potatoes. Since it is the vector of most of the potato viruses, especially leaf roll, effective control or management programs must be followed to grow acceptable seed. It is hot known when the principle time of innoculation takes place in the plants but it is sus­ pected as being in late summer. If this time can be determined it is possible to protect the plants up to this time and then kill the vines to prevent any further infection from developing. As the vines are wilting down they may need protecting from late aphid movement and feeding. Since there are several approaches to insect control available to the grower it was decided to compare three of these, Double systemics, Single systemic plus foliars and Double systemics plus foliars with an untreated area. Double Systems: Thimet 15 G applied at planting time (May 10) at 3 lb ai and Disyston 15 G sidedressed at 3 lb ai at the time of killing (June 24). Double Systemics plus Foliars: The above treatments with addi­ tional commercial foliar program: June 29-Thiodan + Cygon; July 7-Thiodan + Cygon; July 12-MSR; July 19-Monitor; July 27-MSR; August 5-Cygon; August 13-MSR; August 21-Monitor; August 28-Monitor; September 2-MSR. Single Systemic plus Foliars: Thimet applied at planting but without the Disyston sidedress application. Foliars applied as above. Untreated: Received only the Fungicide treatments. The plots consisted of three replications of 16 rows each using Foundation Russet Burbank and Premier Foundation Sebago varieties. Leaf samples were taken at intervals and the aphid populations evaluated for movement or establishment in the plots (Table 1). Harvesting began on August 19-20 with yields and grade recorded for each variety. The adjacent two rows were killed by a vine killer and after wilting (3-5 days later) half of the rows were sprayed with an insecticide (Thiodan-Cygon) for study. This procedure was repeated on September 4-5, 16-17, and October 7-8. The last harvest did not receive the vine killer since a killing frost had terminated vine growth. The yields are presented in Tables 2 and 3. A sample of "B" size tubers was saved from each treatment and have been submitted for indexing in the Florida testing program (Table 4). Dupli­ cate samples of "A" size tubers were retained for indexing for seed quality at the Montcalm Farm in 1975. Results As shown in the insect counts the systemics were effective in holding early infestations down when compared to the adjacent untreated plots. The foliars gave excellent protection. The yields indicate that despite insect feeding on the foliage (i.e. there were heavy populations of Potato Beetles in the plot) good management practices can result in good yields early in the harvest season; however, the protection by the insecticides extended the growth and yield for later harvests. The results of the Florida test will determine if the treatments and dates of harvest have an affect on seed vigor and disease infection of the tubers. Table 1. Aphid and Potato Leafhopper Populations on Potatoes from Montcalm Plots empty table cell Sebago Sebag June Sebago o August August 28 24*For insect identification see footnote 28*For insect identification see footnote 24 16*For insect identification see 27*For insect identification see Sebago June *For insect identification see footnote footnote *For insect identification see footnote *For insect identification see footnote 0 0 6 GPap 2 GPap 1Gpal Burbank Sept. 11 *For insect identification see footnote 1 GPap Burbank August footnote 7 GPap Double Systemics Aug 19 Burbank August 6 GPap 1 GPal 1 GPap 1 P1h BurbankJune BurbankJune 16 0 27*For insect identification see footnote Sept. Sebago 11*For insect identification see footnote empty Sep 4 table Double Systemics cell empty Sep 16 table Double Systemics cell empty table Oct 7 Double Systemics cell 2 GPap Untreated Aug 19 0 1 GPap 9 GPap 4 GPap 1 GPap 5 GPap 0 0 3 GPap 1 PKap 2 GPap 7 GPap 1 GPal 5 GPap 0 3 BPap 0 10 GPap 1GPal 1 PKap 0 0 0 empty table cell empty table cell empty table cell 0 6 GPap 2PKap 8 Plh 47 GPap 16 GPap 13 GPap 10 GPap 8 GPap 9 GPap 4 Plh 9 GPap 1 GPal 8 GPap 1 PKap 1 Plh 2 GPap 5 Plh 1 GPap 1 GPap 5 GPap Untreated Sep 4 Sep 16 Untreated empty table cell empty table cell 3 PKap 3 GPap 1 GPap 1 GPap 1 GPal 2 GPap 2 GPap 1 PKap 7 GPap 11 GPap 1 PKap 2 GPap Oct 7 Untreated empty table cell 1 GPal 1 GPap 4 PKap 2 GPap 1 PKap 2 GPap empty table cell empty table cell empty table cell 0 0 3 GPap 7 PKap 6 GPap 5 PKap 4 Plh 10 GPap 4 PKap 5 GPap 2 PKap 5 Plh 3 GPap 6 PKap 4 Plh 20 GPap 3 PKap 3 Plh 4 GPap 11 PKap 5 GPap 1 PKap 1 PKal 10 Plh 4 GPap 1 PKap 6 Plh 1 GPap Double + Foliar Aug 19 0 empty Sep 4 Double + Foliar table empty cell Sep 16 Double + Foliar table cell empty Oct 7 table Double + Foliar cell Single + Foliar 0 Aug 19 0 0 0 0 0 0 0 1 GPa1 1 GPap 1 GPa1 0 1 GPap 0 0 1 GPap 0 1 GPap 2 GPa1 0 0 0 0 empty table empty cell table cell empty table cell 0 0 0 0 0 8 GPap 3 PKap 5 GPap 8 Plh 1 GPap 5 Plh 1 GPa1 0 1 GPal 0 0 0 0 0 4 GPap 1 GPap 0 0 0 0 Sep 4 Single + Foliar Sep 16 Single + Foliar Oct 7 Single + Foliar 1 GPal 0 1 GPal * GPap = Green Peach (wingless) stet; GPal = Green Peach alate (winged); PKap = Pink 1 GPap 0 1 GPap 0 1 GPap 0 1 GPap 0 0 empty table empty cell table empty cell table cell empty table empty cell table empty cell table cell 0 0 0 0 0 0 0 0 0 0 0 0 apterous; Pkal = Pink alate and Plh = Potato leafhopper Table 2. Yield and Size Distribution of Potatoes from Montcalm Plots a. Burbank empty table cell Lb/100 ft Yield/A Cwt Yield/A Bu Double Systemics 144.0 lb Aug. 20 221.2 Sept. 5 Double Systemics Double Systemics Sept. 17 249.8 Oct. 8 Double Systemics 260.8 Untreated Aug. 20 Sept. 5 Untreated Sept. 17 Untreated Oct. 7 Untreated Single System + Foliars Aug. 19 Sept. 4 Single System + Foliars Sept. 16 Single System + Foliars Oct. 7 Single System + Foliars Double System + Foliars Aug. 19 Sept. 4 Double System + Foliars Sept. 16 Double System + Foliars Oct. 7 Double System + Foliars 153.9 212.0 227.2 258.5 176.2 231.3 250.3 251.5 154.9 210.3 247.5 262.8 % by size distribution to 1 7/8 % by size distribution % by size distribution 1 7/8-10 oz 10 oz -- % by size distribution Off Specific Gravity 222 341 385 402 271 356 386 387 237 326 350 398 239 324 381 405 370 568 643 669 452 594 645 646 395 544 585 663 398 540 636 675 16 7 8 3 14 8 8 7 17 9 9 5 17 9 9 5 79 81 75 72 81 82 80 74 79 77 74 69 80 79 73 71 -- 5 9 16 1 4 6 13 6 9 17 -- 7 8 19 5 7 8 9 4 6 6 6 4 8 8 9 3 5 10 5 1.081 1.086 1.084 1.083 1.082 1.083 1.088 1.087 1.082 1.085 1.086 1.085 1.081 1.084 1.086 1.084 Table 3. Yield and Size Distribution of Potatoes from Montcalm Plots B. Sebago Yield/A Yield/A Bu CWT to 1 7/8 % by Size Distribution % by Size Distribution 1 7/8-3 1/4 "A" % by Size Distribution 3 1/4 +"A" empty table celllb/100 ft 199 267 318 334 145.7 190.0 215.0 196.7 Double Systemics 129.2 Aug. 20 Sept. 5 Double Systemics 173.7 Sept. 17 206.5 Double Systemics 216.8 Oct. 8 Double Systemics Untreated Aug. 20 224 Sept. 5 Untreated 293 331 Sept. 17 Untreated Oct. 7 Untreated 303 Single Systemic + Foliars Aug. 19 199 Sept. 4 Single Systemic + Foliars 235 301 Sept. 16 Single Systemic + Foliars Oct. 7 304 Single Systemic + Foliars Double Systemic + Foliars Aug. 19 180 Sept. 4 Double Systemic + Foliars 253 Sept. 16 Double Systemic + Foliars 323 Oct. 7 Double Systemic + Foliars 319 129.4 152.5 195.2 197.3 117.1 164.5 210.0 207.0 332 445 531 556 373 488 553 505 332 392 503 506 300 422 539 531 "B" 3% 5 5 3 7 5 5 4 7 4 3 2 6 4 2 2 Specific Gravity 1.067 1.072 1.074 1.076 1.067 1.072 1.075 1.071 1.062 1.067 1.073 1.071 1.063 1,067 1.073 1.072 86% 87 80 84 87 84 77 70 90 81 73 75 86 77 69 63 11% 8 15 13 6 11 18 26 3 15 24 23 8 19 29 35 Table 4. Potato Seed Samples from the Plots Which Were Submitted for the Florida Test Variety: Russet Burbank and Sebago Treatment Sample Nos. R.B. Sample Nos. Seb. 1 37 Double Systemic Dates Vines Killed --- 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 Dates Insecticide Applied --- — — — — Untreated Double Systemic + Foliar —— Single Systemic + Foliar — Double Systemic Untreated Double Systemic + Foliar Single Systemic + Foliar --- Aug. 20 Aug. 20 — Aug. 20 — Aug. 20 — Double Systemic Untreated Double Systemic + Foliar Single Systemic + Foliar Aug. 20 Aug. 20 Aug. 20 Aug. 20 Aug. 23 Aug. 23 Aug. 23 Aug. 23 ___ Double Systemic — Untreated Double Systemic + Foliar — Single Systemic + Foliar — --- — — — Double Systemic Untreated Double Systemic + Foliar Single Systemic + Foliar ___ Sept. 5 Sept. 5 — Sept. 5 — Sept. 5 — Double Systemic Untreated Double Systemic + Foliar Single Systemic + Foliar Sept. 5 Sept. 5 Sept. 5 Sept. 5 Sept. 11 Sept. 11 Sept. 11 Sept. 11 — Double Systemic — Untreated Double Systemic + Foliar — Single Systemic + Foliar — — — — — Double Systemic Untreated Double Systemic + Foliar Single Systemic + Foliar ___ Sept. 18 Sept. 18 — Sept. 18 — Sept. 18 — ___ --- Double Systemic — — Untreated Double Systemic + Foliar — — Single Systemic + Foliar — --- Dates Harvest Aug. 20 Aug. 20 Aug. 19 Aug. 19 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Sept. 5 Sept. 5 Sept. 4 Sept. 4 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Oct. 17 Sept. 17 Sept. 17 Sept. 16 Sept. 16 Oct. 9 Oct. 9 Oct. 9 Oct. 9 Oct. 8 Oct. 7 Oct. 7 Oct. 7 B. Evaluation of Soil Systemic and Foliar Insecticides at the Muck Experimental Farm. Objective and Methods. Plots were established at the Muck Experimental Farm to compare soil applications of systemic insecticides with foliar applications of other materials on foliar feeding insects of potatoes. The potatoes were planted on May 20 using cut Sebago seed in three replications of paired 25 foot plots. The soil systemics were applied as granules in the open furrow after planting and before covering the seed. Flea beetle feeding scars were counted on the systemic plots at the time of hilling, also at which time some of the systemic plots received another application of the granular form­ ulations as a sidedress band. The other plots as well as certain of the systemic plots were sprayed with a hydraulic sprayer delivering 100 gal/A on July 12, 24, August 9 and 26. The insects were sampled periodically by direct counting infestations per compound leaf or by insect sweep net. The data are presented in Tables 5-8. The potatoes were harvested on October 22 and the yields presented in Table 9. The results of another study to determine the value of seed treatments with Orthene for early season insect control is given in Table 10. Results. The flea beetle damage counts indicated that most of the systemic materials were in the plants and killing flea beetles soon after the plants emerged. They were still affecting the insects until mid July and certain ones were still effective on aphids into August. There was a wide variation in the results of the foliar materials on certain insects. This is expected since some of the materials are very specific in their insecticidal activity. The yields indicate that with good fertilization and maintenance, muckgrown potatoes can withstand considerable insect feeding without extensive loss in yield potential. It appears that in-row applications of certain of the systemics slowed down early growth and affected the yield since these appear to be less than in the unheated plot. Table 5. Foliar Insect Control on Potatoes Material * Thimet G Thimet G + Cyg Disyst G Disyst G + F Disyst G Disyst G + S + F Temik G 3 Temik G 2 DS 15647 G 3 DS 15647 GS Furadan G Furadan G + Disy G Bay Hox G + E SD 8832 + Thio Orth G + F Sandoz Monitor Bay Hox + Guthion CGA 18809 CGA 15324 C-8353 Furadan Pirimor 2 Pirimor 4 Carzol Dyfonate Imidan Dyfonate + Imidan Sevimol + Cygon Lannate Rohm & Haas Untreated Untreated Potato Leafhoppers (Insects/30 sweeps)July 19 3 Potato Leafhoppers (Insects/30 sweeps) July 9 Potato Leafhoppers (Insects/30 sweeps)August22 Potato Leafhoppers (Insects/30 sweeps) August 9 July 31 Potato Leafhoppers (Insects/30 sweeps) Sept. Potato Leafhoppers (Insects/30 sweeps) Nymphs/15 leaves Aug. 21 Nymphs/15 leaves Totals Potato Leafhoppers (Insects/30 sweeps) (7/19-9/3) Sept. 3 11 10 17 16 22 18 9 12 8 5 9 11 40 17 43 49 45 57 49 51 47 46 43 48 40 58 39 36 43 52 42 42 54 39 49 26 53 38 54 29 27 14 22 34 66 81 64 42 47 43 63 63 53 66 39 101 82 63 152 52 51 52 49 55 110 126 51 15 54 38 30 17 29 47 8 18 57 44 24 23 21 27 12 68 35 33 14 3 18 68 36 62 12 23 15 18 18 53 39 93 90 122 112 86 71 72 100 40 30 80 80 49 87 57 82 40 85 84 68 37 30 74 77 57 130 47 35 28 74 51 82 91 106 99 72 93 99 96 84 114 51 41 97 116 65 63 60 97 48 101 74 78 33 33 89 77 45 93 36 47 55 65 61 103 129 8 6 18 10 13 7 21 26 3 8 34 34 5 7 2 5 - 4 9 19 - 1 7 4 6 10 1 2 1 4 3 12 13 297 259 292 306 266 245 235 314 116 119 302 340 224 244 182 258 143 321 265 251 150 106 289 308 207 447 148 158 151 210 188 360 398 3 2 - 1 2 1 3 15 - 1 20 12 3 3 - 3 2 9 3 3 4 4 5 5 7 9 - 2 1 3 1 27 14 - 1 1 - - - - - - 1 2 - - - - — - — 2 — — — — - - - - - - - - 3 2 *For rates of application and treatment dates refer to Table 9. Table 6. Foliar Insect Control on Potatoes * Material Thimet G Thimet G + Cyg Disyst G Disyst G + F Disyst G Disyst G + S + F Temik G 3 Temik G 2 DS 15647 G 3 DS 15647 GS Furadan G Furadan G + Disy G Bay Hox G + E SD 8832 + Thio Orth G + F Sandoz Monitor Bay Hox + Guthion CGA 18809 CGA 15324 C-8353 Furadan Pirimor 2 Pirimor 4 Carzol Dyfonate Imidan Dyfonate + Imidan Sevimol + Cygon Lannate Rohm & Haas Untreated Untreated Aster Leafhoppers (Insects/30 sweeps) Aster Leafhoppers (Insects/30 sweeps) July 9 August 9 Aster Leafhoppers (Insects/30 sweeps) Aster Leafhoppers (Insects/30 sweeps) Aster Leafhoppers (Insects/30 sweeps) July 19 August 22 Totals (7/19-9/3) Aster Leafhoppers (Insects/30 sweeps) July 31 Aster Leafhoppers (Insects/30 sweeps) Sept 3 -- 12 14 10 4 5 7 2 9 5 5 2 3 29 20 13 15 14 8 33 14 23 9 17 38 19 13 14 24 13 24 22 17 27 6 5 3 3 - 6 8 5 5 2 5 9 6 6 5 9 2 5 5 9 5 3 6 8 3 9 9 8 3 6 5 9 6 6 4 2 2 5 2 3 1 - 3 4 10 7 8 9 14 15 19 12 8 9 6 16 17 18 16 7 18 11 8 19 20 6 6 7 8 8 5 5 6 3 2 2 5 6 6 10 6 9 4 3 6 8 6 7 11 7 7 9 9 7 9 11 8 7 1 2 5 7 8 4 4 4 4 3 3 3 9 8 8 13 14 8 11 3 6 3 12 12 11 6 4 3 14 21 6 6 6 - 1 1 - — - - — 2 1 1 1 1 1 1 3 3 1 3 - 1 2 _- 2 - - - 2 - - — - 1 20 29 27 22 24 16 17 29 18 16 10 17 54 41 40 42 47 25 52 34 48 23 39 69 45 39 36 47 42 47 45 36 50 *For rates of application and treatment dates refer to Table 9. Potato Fleabeetles (Insects/30 sweeps)July Table 7. Foliar Insect Control on Potatoes Potato Fleabeetles (Insects/30 sweeps) August 9 212 224 188 178 191 183 155 131 176 159 132 124 262 280 316 326 280 211 249 300 289 288 258 -39 264 208 299 266 294 312 317 186 196 Material * Thimet G Thimet G + Cyg Disyst G Disyst G + F Disyst G Disyst G + S + F Temik G 3 Temik G 2 DS 15647 G 3 DS 15647 GS Furadan G Furadan G + Disy G Bay Hox G + E SD 8832 + Thio Orth G + F Sandoz Monitor Bay Hox + Guthion CGA 18809 CGA 15324 C-8353 Furadan Pirimor 2 Pirimor 4 Carzol Dyfonate Imidan Dyfonate + Imidan Sevimol + Cygon Lannate Rohm & Haas Untreated Untreated 31 174 179 159 176 252 204 197 140 164 101 197 83 201 249 240 287 186 186 155 240 264 77 126 284 363 159 216 224 186 222 230 171 96 Potato Fleabeetles (Insects/30 sweeps) Potato Fleabeetles (Insects/30 sweeps) July 9 July 19 15 37 81 20 32 40 58 25 27 33 52 25 7 39 15 49 18 9 1 25 10 19 50 2 62 51 75 57 44 33 52 76 60 47 40 75 41 12 48 26 76 39 50 25 48 43 64 41 52 39 17 32 46 42 12 37 31 22 46 16 38 47 18 60 35 20 Potato Fleabeetles (Insects/30 sweeps) August 22 149 209 204 177 187 177 161 158 137 131 148 120 262 293 344 312 379 307 229 359 277 231 356 302 135 356 254 305 357 359 273 308 197 Potato Fleabeetles (Insects/30 Potato Fleabeetles (Insects/30 Sept. sweeps) 3 56 55 60 83 76 47 40 74 43 40 33 59 73 39 40 53 36 72 33 62 36 4 25 88 42 31 26 16 24 34 17 63 34 Totals (7/19-9/3) 528 748 651 672 739 663 592 552 538 456 529 436 849 918 973 1054 927 816 678 987 905 625 813 954 843 771 837 823 883 943 875 746 543 *For rates of application and treatment dates refer to Table 9. Potato Fleabeetles (Insects/30 sweeps)Feeding Scars/ sweeps) leaflet 6/20 1.6 1.8 3.4 4.5 4.9 4.8 0.9 1.3 1.2 2.0 0.9 0.6 9.6 5.9 5.5 --- --- ---- --- --- --- --- — — — --- --- --- --- --- --- 9.7 6.4 --- --- Table 8. Foliar Insect Control on Potatoes Aphids (Insects/30 sweeps) Aphids (Insects/30 sweeps)July Aphids (Insects/30 Aphids (Insects/30 sweeps) Aphids (Insects/30 sweeps) Material * Thimet G Thimet G + Cyg Disyst G Disyst G + F Disyst G Disyst G + S + F Temik G 3 Temik G 2 DS 15647 G 3 DS 15647 GS Furadan G Furadan G + Disy G Bay Hox G + E SD 8832 + Thio Orth G + F Sandoz Monitor Gay Hox + Guthion CGA 18809 CGA 15324 C-8353 Furadan Pirimor 2 Pirimor 4 Carzol Dyfonate Imidan Dyfonate + Imidan Sevimol + Cygon Lannate Rohm & Haas Untreated Untreated Sept. Totals (7/19-9/3) July Aphids (Insects/30 sweeps) 3 9 Aphids (Insects/30 sweeps) July 19 — 53 1 22 3 1 - - 5 - 12 1 8 2 1 2 5 3 28 3 1 50 2 3 67 5 1 3 64 1 — 47 6 32 1 3 26 1 2 — 26 4 19 1 6 7 1 1 17 1 3 39 2 4 221 1 7 — 84 2 82 3 4 303 2 4 — 79 6 69 2 3 383 1 3 2 10 267 221 3 5 135 2 2 — 58 3 43 2 10 137 2 4 8 274 1 8 113 7 August sweeps)August 22 9 187 30 7 179 132 14 66 12 67 21 59 6 19 173 256 13 310 26 17 170 124 289 157 72 67 20 33 231 121 52 36 59 61 6 34 105 646 71 321 43 106 1076 68 901 62 151 55 464 578 104 156 551 843 124 841 121 22 364 285 361 57 357 137 556 287 519 31 6 2 14 - 2 - 3 5 8 6 50 17 3 5 8 3 3 3 8 2 9 5 11 9 14 57 26 17 2 54 12 47 84 276 213 165 90 99 72 224 327 416 260 516 281 117 295 201 106 87 183 947 450 1277 1279 303 599 1080 1041 1217 1116 446 753 565 1022 1010 Aphids/15 Aphids/15 leaves leaves 9/3 8/21 6 30 64 62 - 9 10 11 3 4 3 6 1 11 4 10 6 15 36 33 2 4 6 8 8 19 9 16 5 22 2 4 11 10 4 14 59 123 20 32 87 139 26 44 35 72 49 241 30 24 25 54 68 283 7 30 58 116 15 39 22 57 22 13 13 28 *For rates of application and treatment dates refer to Table 9. Table 9. Yields and Size of Tubers from Potato Foliar Plots Type of Foliar Applications: Hydraulic sprayer delivering 100 gal/A. Dates of Application: July 12, 24, Aug. 9 & 26, 1974 Materials Rate/A (Tox.) Placement Yield/Acre CWT Bu. Yield/Acre % Size Distribution Less than 1-7/8" % Size Distribution 1-7/3" and over Thimet 15G Thimet 15G + Cygon 267 Disyston 15G Disyston 15G +Disyston 6SC* Disyston 15G Disyston 15G + Disyston 15G + Monitor 4WDL Temik 15G Temik 15G Diam. Sham. 15647 10G Diam. Sham. 15647 10G + Diam. Sham. 15647 10G Furadan 10G Furadan 10G + Disyston 15G Bay Hox 1901 10G + Bay Hox 1901 4E SD-8832 10G +Thiodan 3E Orthene 5% G + Orthene 75 S Sandoz 201 4E Monitor 4WDL Bay Hox 1901 4E + Guthion 2SC CGA 18809 50 WP CGA 15324 4E C-8353 2EC Furadan 4F** Pirimor 50 WP + Bio Film** Pirimor 50 WP + Bio Film** Carzol 97% Dyfonate 4F Imidan 70W ** Dyfonate 4F + Imidan 70W 3 lb 3 lb 1/2 lb 3 lb 3 lb 1 lb 3 lb 3 lb 3 lb 1 lb 3 lb 2 lb 3 lb 2 lb 1 lb 3 lb 3 lb 3 lb 3 lb 1/2 lb 3 lb 3/4 lb 3 lb 1 lb 3/4 lb 1 lb 1/2 lb 1/2 lb 3/4 lb 3/4 lb 3/4 lb 1 lb 2 oz 6 oz 4 oz 6 oz 1/2 lb 1 lb 1 lb 3/4 lb 3/4 lb In-row In-row Foliar In-row In-row Foliar In-row In-row Side-dress Foliar In-row In-row In-row In-row Side-dress In-row In-row Side-dress In-row Foliar In-row Foliar In-row Foliar Foliar Foliar Foliar Foliar Foliar Foliar Foliar Foliar 255 220 253 255 242 225 362 324 363 333 374 356 316 315 346 304 308 293 276 309 307 291 311 425 367 422 425 403 375 603 540 605 555 623 593 527 525 577 507 513 488 460 515 512 485 518 Foliar Foliar Foliar Foliar Foliar 309 345 266 293 326 515 575 443 488 543 5 Serimol 4 + Cygon 267 Lannate 1.8L Rohm & Haas 218 5EC Untreated Untreated 1 lb 1/2 lb .9 lb 1 lb -- -- Foliar Foliar Foliar — --- 322 340 314 359 356 537 567 523 598 593 *Not applied on Aug. 26. **Additional application on Sept. 10 for residue study. 5% 4 6 5 6 6 4 3 4 3 5 5 7 7 4 7 5 8 7 6 6 5 7 5 5 8 4 6 5 4 6 5 95% 96 94 95 94 94 96 97 96 97 95 95 93 93 96 93 95 92 93 94 94 95 93 95 95 92 96 94 95 96 94 95 95 Table 10. Seed and Soil Treatments for Potato Insect Control Variety of Seed: Norchip (cut seed) Date Planted: May 20, 1974; Phytotoxicity ratings and flea beetle data taken June 25, 1974 Material and Formulation Orthene 12.5% ST Orthene 12.5% ST Orthene 12.5% ST Orthene 12.5%--Ortho 15% ST Orthene 12.5%—Ortho 15% ST Orthene 12.5%--Ortho 15% ST Orthocide (Captan 80) Orthene 5% Gran*** Furadan 10% Gran *** Untreated Rate (oz/cwt) Rate (oz/cwt) Tox Form 0.5 oz 1.0 oz 2.0 oz 0.5 oz 1.0 oz 2.0 oz 1.0 oz 3 lb 2 lb 4 oz 8 oz 16 oz 4 oz 8 oz 16 oz 1.3 oz 60 lb 20 lb empty table —- Phyto rating * 3.8 3.3 4.0 2.5 2.5 3.0 1.0 1.0 1.0 cell 1.0 Flea beetle ** scars/leaf 1.3 1.7 1.8 4.1 0.5 0.3 9.8 5.2 1.6 10.0 Yield/A CWT 302 307 257 287 338 381 333 328 360 302 Yield/A Bu 503 512 488 478 563 635 555 547 600 503 % Grade by Size % Grade by Size (B's) (A’s) 6% 94% 7% 93% 6% 94% 8% 92% 5% 95% 94% 6% 11% 89% 14% 86% 11% 89% 16% 84% *Phytotoxicity ratings: 1—No apparent retardation — 5--Severe retardation **Mean of five leaflets/replication ***Applied in seed furrow at time of planting CORN HYBRIDS, PLANT POPULATION AND IRRIGATION E. C. Rossman and Barry Darling Department of Crop and Soil Sciences Table 1 presents performance data for 76 commercial corn hybrids evalu­ ated in 1974 with irrigation and without irrigation. Eight inches of water were applied in 6 applications on July 16, 22, 27, 31, August 2, September 7. Bouyoucous soil moisture blocks were placed at 6, 12, 18 and 24-inch depths in both irrigated and unirrigated plot areas. Irrigated yields averaged 112.1 bushels per acre and 102.7 unirrigated. The average difference in favor of irrigation was only 9.4 bushels (9.1%). Difficulties with and inadequate soil moisture monitoring using Bouyoucous blocks and meter may have led to inadequate irrigation during August. This was the second year in which less than expected response to irrigation occurred. In 1973, irrigation averaged 113.6 bushels versus 101.0 unirrigated — a difference of only 12.6 bushels (12.5%). Wet soil conditions at and following planting hindered early growth and development. Extreme hot and dry weather in late August and early September after irriga­ tion had ceased probably contributed to a low response from irrigation. Hybrids ranged from 65.3 to 133.7 irrigated and 57.8 to 121.9 bushels per acre without irrigation. Hybrids signficantly better than the average yield (arranged in order of increasing grain moisture content at harvest) are listed below. Fourteen of these 19 hybrids were in the highest yielding group for both irrigated and unirrigated plots. Irrigated Michigan 2853 (3X) Michigan 333-3X (3X) Asgrow RX53 (2X) Michigan 3102 (2X) Funk Exp. 26190 (3X) Michigan 396-3X (3X) Michigan 407-2X (2X) Michigan 410-2X (2X) Pride R290 (2X) Cowbell SX7440 (2X) Funk G4444 (2X) Funk G4321 (2X) Funk G4404 (2X) Super Crost 1901 (2X) Migro M-1130 (2X) Michigan 575-2X (2X) Unirrigated Michigan 333-3X (3X) Super Crost 1692 (2X) Asgrow RX53 (2X) Michigan 3102 (2X) Funk Exp. 26190 (3X) Michigan 396-3X (3X) Michigan 407-2X (2X) Michigan 410-2X (2X) Pride R290 (2X) Cowbell SX7440 (2X) Funk G4444 (2X) Funk G4321 (2X) Asgrow RX64 (2X) Funk G4404 (2X) Super Crost 1901 (2X) Michigan 572-3X (3X) Michigan 575-2X (2X) Cowbell SX7480 (2X) Table 1 NORTH CENTRAL MICHIGAN Montcalm County - Irrigated vs. Slot Irrigated One, Two, Three Year Averages - 1974, 1973, 1972 Hybrid (Brand - Variety) % Moisture 1974 % Moisture % Moisture 2 Yrs 3 Yrs Bushels per acre1974 Irrig Bushels per acre 1974 Not Irrig Bushels per acre Bushels per acre 2 Bushels per acre 2 years years Irrig Not Irrig 3 years Irrig Bushels per acre3 years Not Irrig % Stalk lodging 1974 Irrig % Stalk lodging 1974 Not Irrig Pioneer 3965 (3X) Super Crost 1610 (2X) Michigan 2833 (3X) Wolverine W128 (2X) 1 Michigan 2853 (3X) Blaney B100 (2X) Michigan 275-2X (2X) Michigan 280 (4X) Super Crost 1103 (2X) Northrup King PX20 (2X) 1,2 Michigan 333-3X (3X) DeKalb XL311 (3X) Migro M-0101 (2X) Blaney B302 (2X) Asgrow RX42 (2X) 2 Super Crost 1692 (2X) 1,2 Asgrow RX53 (2X) Cardinal SX100 (2X) Pioneer 3958 (2X) Wolverine W127 (2X) 1,2 Michigan 3102 (2X) 1,2 Funk Exp. 26190 (3X) Blaney 7305 (2X) Migro M-1020 (Sp.) -- -- -- -- -- -- 27.4 27.5 27.5 27.7 27.9 28.1 28.1 25 28.2 25 28.6 —- —- —- 29.1 29.7 29.8 29.8 30.2 31.0 31.2 31.8 31.8 32.6 32.9 -- —— 24 26 -- -- 24 24 —- 26 26 -- -- 27 27 29 -- 29 —- -- -- -- -- 27 -- -- -- -- -- -- -- -- -- -- -- -- -- 32.9 33.6 34.0 34.1 105.0 108.2 111.9 104.8 122.7 95.3 110.2 115.9 65.3 108.3 123.5 101.5 110.8 120.5 118.9 119.2 122.8 96.8 111.1 111.9 125.1 130.8 106.7 115.7 -- 101.5 104.3 103.8 99.3 108.2 83.0 106.2 107.7 57.8 100.7 115.4 86.5 98.1 111.0 105.6 111.9 114.4 89.4 -- 98.3 108.4 -- 116.0 116.2 -- 103.8 -- 103.1 -- -- 113 105 -- 107 108 -- -- 120 102 -- -- 118 113 127 104 -- -- -- -- 103 93 -- -- 101 100 -- -- 106 87 -- -- 106 101 117 95 -- -- -- -- -- -- -- -- -- 113 117 -- -- 129 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 101 108 -- -- -- -- -- -- -- -- -- -- -- --__ -- -- -- -- -- -- -- -- -- -- 0.0 0.0 0.9 5.1 1.3 1.7 0.9 2.0 5.1 0.0 0.9 0.0 0.0 0.0 0.0 0 0 0.0 1.6 0.0 0.0 0.0 0.0 0.0 0.0 3 3 3 3 -- 0.0 1.6 -- 0.0 4.2 1.4 -- -- 0.8 0.0 4.3 5.6 -- 0.0 -- 0.0 0.0 1.6 -- 3.2 -- 0.0 1.7 0.0 0.8 -- 0.0 0.0 -- -- 0.0 0.0 -- 0.8 -- -- 1.6 1 2 0 1 3 2 4 4 -- -- 4 4 -- -- 1 2 -- -- 1 2 2 1 -- -- -- -- -- -- % Stalk lodging2 years Irrig % Stalk lodging 2 years Not Irrig -- -- % Stalk lodging3 years Irrig -- -- -- -- -- -- % Stalk lodging 3 years Not Irrig -- -- -- -- -- -- 3 7 -- -- 7 6 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Table 1 (Continued) Acco UC2301 (2X) 34.1 30 30 118.2 104.7 Wolverine 46A (4X) Acco UC1901 (2X) 1, 2Michigan 396-3X (3X) Northrup King PX32 (2X) 1, 2Michigan 407-2X (2X) Cowbell SX4095 (2X) Northrup King PX25 (2X) Funk G4195 (3X) Pioneer 3797 (3X) Funk G4252 (3X) Cardinal SX105 (2X) Migro M-1101 (2X) Wolverine 59 (4X) DeKalb 15A (2X) DeKalb XL12 (2X) 1, 2 Michigan 410-2X (2X) Funk G4343 (2X) Cowbell SX7300 (2X) 1, 2 Pride R290 (2X) Pioneer 3785 (2X) Acco UC231 (4X) Super Crost S25 (2X) Blaney BX-AA (2X) Super Crost S27 (2X) Funk G4288 (3X) 1, 2 Cowbell SX7440 (2X) 1, 2 Funk G4444 (2X) 1, 2 Funk G4321 (2X) DeKalb XL21 (2X) Cowbell SX4100 (2X) 2 Asgrow RX64 (2X) -- -- -- -- — __ 92.7 29 — 103.4 126.9 29 34.2 34.3 34.4 34.4 — — 118.7 106.5 -- 34.5 87.5 88.1 115.2 133.6 121.9 30 29 30 69.8 97.7 28 — 111.7 106.8 30 90.6 121.0 34.6 — — 80.7 34.6 — — 109.5 34.7 34.7 — -- 30 34.8 35.2 — — 121.9 30 94.1 35.3 — 90.4 36.1 30 36.2 36.3 103.4 100.1 104.3 115.9 77.4 -- 102.4 106.5 87.2 86.8 -- 30 31 36.3 36.3 36.4 36.8 37.1 — — 112.9 114.0 133.1 83.2 101.5 90 3 101.4 133.5 115.1 102.0 31 30 _ 31 30 — 30 31 32 — 31 37.1 37.2 37.5 37.6 37.7 31 — 31 33 32 32 33 33 32 — — -- 92.1 88.5 106.3 113.4 100.2 111.2 85.2 105.5 115.7 109.4 — 37.7 37.7 33 33 129.1 37.7 33 — 132.2 ___ 37.7 33 105.4 — 111.7 100.2 — 37.8 — 37.8 — — 118.6 113.5 129.3 117.6 120.7 114.6 98.7 132 128 111 — 120 107 128 134 106 104 115 103 110 133 107 108 121 — 90 116 118 120 123 -- -- -- -- -- -- -- 106 96 113 120 96 94 100 97 99 134 — 136 157 -- 121 127 114 -- -- -- -- -- -- -- -- 140 130 140 — 139 138 138 112 94 94 — 104 — 88 — 104 108 102 110 — — — 119 -- 124 136 -- 106 113 106 123 110 124 — 120 123 121 -- -- -- -- -- -- -- -- — — — — 157 134 119 114 — 103 — — — — — — — — — 0.0 0.0 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.4 0.0 0.0 0.9 0.0 0.0 0.0 0. 0 0.0 0.0 0.0 0.0 0.0 0 0 0.0 1.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.0 0.8 2.0 -- 3 3 2 -- 3 -- 3.5 0.8 -- 0.0 1.7 -- 0.0 -- 0.0 0.8 0.0 -- 0.0 0.0 1.7 0.8 0 8 -- 1.5 0.0 -- 1.6 0.0 0.0 0 0 0.0 -- 1.5 1.5 0.0 2.8 0.0 -- 0.0 2 2 2 2 2 2 1 3 4 0 1 3 3 2 3 2 7 — 3 -- 4 -- -- 5 2 4 3 5 3 2 4 4 1 3 1 -- 3 4 2 -- -- -- -- 1 -- 1 8 1 -- 4 1 2 -- 3 0 1 2 0 2 1 4 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 2 -- 2 — 3 -- 2 1 5 4 1 4 -- 3 3 2 3 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 132 122 128 115 121 129 118 120 —- 117 120 127 - 116 90 to 134 — 110 116 103 110 112 112 105 105 109 111 —— 104 87 to 120 6 -- -- -- -- -- -- -- -- -- -- -- — 142 147 — 148 147 139 135 —— 136 113 to 156 5 -- -- -- -- -- -- -- __ __ __ __ —— 126 130 — 127 125 123 118 -- 120 100 to 136 5 0.0 0.0 0.0 0.0 2.5 0.0 0.9 1.7 0.0 0.0 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.6 0.9 0.4 0.8 0.0 0.0 __ 0.0 1.6 0.9 0.0 0.8 0.0 0.0 __ 2 2 1 2 1 4 2 2 2 2 1 0.8 0.0 0.0 0.0 __ 0.0 __ -- 0.0 0.0 __ 0.0 __ 0.0 __ -- 0.0 2 2 2 3 5 0 1 __ 1 1 1 __ __ __ __ -- __ __ __ __ __ __ __ __ __ __ __ __ __ -- __ __ __ 2 3 2 4 1 2 __ __ __ __ __ 6 4 2 4 3 2 __ __ __ __ -- __ __ __ __ __ 0.7 2 2 4 3 0.0 to 5.1 empty table cell 0.0 0 to to 4 5.6 empty table empty table cell cell 0 2 1 to 5 to6 to 7 empty table cell empty table cell empty tablecell Acco UC3201 (2X) Funk G4366 (3X) 1 Migro M-1130 (2X) 1, 2 Michigan 575-2X (2X) Funk G-L2354 (Sp.) HL Northrup King PX529 (3X) 39.4 Blaney B606 (2X) Migro M-1010A (2X) Funk GWX302 (Sp.) WX 2 Cowbell SX7480 (2X) -- 34 39.1 39.1 39.2 39.3 -- 39.4 34 95.7 33 — 105.3 34 -- 38.5-- -- 93.1 97.5 126.7 107.4 116.8 -- 129.5 114.3 111.0 -- -- -- 106 7 39.4 -- 110.1 101.8 -- 39.7 -- 93.0 -- 96.6 39.8 -- 113.1 107.4 40.4 — — 117.0 113.8 -- -- -- -- 109 3 35.0 27.4 to 40.4 30 24 to 34 31 25 to 34 112.1 102.7 65.3 to 133. 7 57.8 to 121.9 Table 1 (Continued) 1, 2 Funk G4404 (2X) Pioneer 3780 (2X) 1, 2 Super Crost 1901 (2X) 2 Michigan 572-3X (3X) Pioneer 3773 (2X) 33 — 125.5 117.7 117.5 109.6 33 37.8 37.9 38.0 — — 133.7 122.0 33 38.2 33 — 103.6 38.5 120.0 -- 115.4 99.3 32 32 P.A.G. SX69 (2X) Acco UC3301 (2X) Migro M-1213 (2X) Michigan 500-2X (2X) Northrup King PX48 (2X) 107.0 102.6 38.6 38.8 105.9 105.2 38.8 38.8 101.4 38.9 — — 110.0 103.5 34 33 33 120.4 34 33 — 110.2 33 110.5 33 Average Range Least significant difference 1 Significantly better than average yield, irrigated 1974. 2 Significantly better than average yield, not irrigated 1974. 10.9 1.7 9.6 .8 .6 7 empty table cell Planted Harvested Soil type Previous crop Population Rows Fertilizer 1974 May 4 Oct. 26 1973 May 8 Oct. 17 1972 May 5 Oct. 25 Montcalm sandy loam Montcalm sandy loam Montcalm sandy loam Sorghum-sudan seeded to rye in fall Sorghum-sudan seeded to rye in fall Sorghum-sudan seeded to rye in fall 20,500 30" 18,700 30" 20,100 30" 150-120-170 277-130-130 258-145-145 Soil test: pH 6.1 5.6 5.5 P Soil test: K Soil test: Irrigation: 340 (very high) 297 (very high) 420 (very high) 198 (high) 8 inches 175 (medium) 5 inches 178 (medium) 6 inches Farm Cooperator: Theron Comden, Lakeview County Extension Director: James Crosby, Stanton Table 2 gives the average, highest, and lowest yields for corn hybrids irrigated and not irrigated for a 7-year period, 1968-1974. The average yielding hybrid has given a response of 46 bushels to irrigation, the highest yielding hybrids have responded with 61 bushels added yield, while the lowest yielding hybrids have given only 27 bushels added yield with irrigation over the seven-year period. These results demonstrate the importance of choosing high yielding hybrids to maximize returns from irrigation with little if any additional cost. Plant population x irrigation Five hybrids at 4 plant populations irrigated and not irrigated were grown in each of 7 years, 1968-1974, Table 3. Over the seven-year period, a population of 23,300 has given the highest yield (167 bushels) when irri­ gated while 19,300 has given the highest yield (110 bushels) without irriga­ tion. The 23,300 population irrigated gave the highest yield in six out of the seven years. Moisture content of grain at harvest has averaged .5-1.0% higher for the higher plant populations. Stalk lodging at harvest has also increased slightly with increased plant population. Table 2. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for 7 years, 1968-1974. No. of hybrids tested Average age Aver Not Irrigated Irrigated Highest Highest Not Irrigated Irrigated Lowest Irrigated Lowest Not Irrigated Year 1974 1973 1972 1971 1970 1969 1968 AveragesEmpty table cell 76 72 72 56 64 63 56 112 114 157 163 144 146 136 139 103 101 137 28 103 86 96 93 134 138 206 211 194 185 182 179 122 120 179 42 128 109 123 110 65 78 99 91 95 97 92 88 58 73 91 11 70 56 65 61 Table 3. Average yield at 4 plant populations irrigated and not irrigated for 7 years, 1968-1974. 15,200 15,200 19,300 19,300 23,300 Irri­ gated Not Irri­ gated Irri­ gated Not Irri­ gated Irri­ gated 23, 300 Not Irri­ gated 27,600 27,600 Irri­ gated Not Irri­ gated 118 108 152 173 122 126 144 135 100 97 132 37 91 91 114 95 130 134 187 189 144 158 169 159 111 116 159 35 112 109 130 110 135 128 191 191 158 173 193 167 98 106 149 20 93 96 107 96 120 108 161 181 151 148 178 149 94 102 144 11 85 86 89 87 Year 1974 1973 1972 1971 1970 1969 1968 Average