1979 Research Report MONTCALM EXPERIMENT STATION Michigan State University Agricultural Experiment Station ACKNOWLEDGMMTS 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, the Michigan Potato Industry Commission, 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 Integrated Project - Influence of Selected Production Management Inputs on the Yield, Quality and Storability of Potatoes Nematology Component G.W. Bird and J. Noling.................................... ................................................................ 4 The Influence of Selected Management Inputs on Nutrient Composition of Potato Petioles M L. Vitosh................................................................................................................................. . 28 Influence of Pre-Storage Treatments on Out-of Storage Quality B. F. Cargill.............................................................................................................................. 36 New Variety Evaluation R.W. Chase, R. B. Kitchen, R.K. Peterson . . . . ......................................................... 50 To Evaluate Several Selections for Their Yield and Processing Potential Under Michigan Conditions R.W. Chase, R.B. Kitchen, R.K. Peterson........................................................................ 57 The Evaluation of PIX, A Plant Regulator, For Its Effect on Potato Plant Growth, Tuber Number, and Tuber Quality R.K. Peterson, R.W. Chase, R.B. Kitchen........................................................................ 63 Correlation of the Sucrose-Rating System to Variety, Harvest and Storage Jerry Cash and Richard Chase................................................................................................ 67 Fertilizer Correlation Study M.L. Vitosh......................................................................................................................................... 73 Foliar Fertilizer Study with Potatoes M.L. Vitosh............................................................................................................................................ 77 1979 Soil Fertilizer Study with Potatoes M.L. Vitosh............................................................................................................................................ 80 Weed Control in Potatoes Meggitt and Richard Chase....................................................................................... 85 Impact, Biology and Monitoring of Insect and Nematode Pests of Potatoes E. Grafius, G.W. Bird, J.W. Noling, and MA. Otto...................................................... 88 Effect of Nematicides on on the Control of Pratylenchus Penetrans and Potato Yields G.W. Bird and J. Noling............................................................................................................... 102 Effect of Potato Seed Piece Treatment on Stand and Yield - 1979 H. S. Potter....................................................................................................................................... 104 1979 Field Trials on Potatoes to Compare the Applications of Fungicides for Disease Control by Solid Set Irrigation, by Boom Sprayer and by Aircraft H. S. Potter....................................................................................................................................... 106 1979 Field Trials on Potatoes Comparing Application of Fungicides by Center Pivot Irrigation and by Aircraft H. S. Potter....................................................................................................................................... 109 Potato Insect Control Studies A. F. Wells........................................................................................................................... 112 Control of Root Lesion Nematode (Pratylenchus Penetrans) Associated with Navy Beans G.W. Bird and A P. Elliot................................................................................................ 119 Control of Root Lesion Nematode (Pratylenchus Penetrans) Associated with Fine Dry Bean Vaaieties G.W. Bird and A P. Elliot................................................................................................ 121 Control of Root Lesion Nematode (Pratylenchus Penetrans) Associated with Soybeans G.W. Bird and A P. Elliot..................................................................................................... 123 Influence of Experimental Nematicides on Pratylenchus Spp. and on Yield of Field Corn G.W. Bird and E. Casewell.......................................................................................................... 125 Large Seeded Colored Bean Evaluation Trial Jerry Taylor and M. W. Adams . ............................................................................... .127 Corn Hybrids, Plant Population and Irrigation E. Rossman and Keith Dysinger ............................................................................................ 129 MONTCALM BRANCH EXPERIMENT STATION RESEARCH REPORT R.W. Chase and MH. 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 thirteen 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 1979. 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 twelve year temperature and rainfall data. Temperatures during 1979 were not too much different than the 12 year average. August was somewhat cooler and there were many cloudy and high humidity days. During the entire growing season there were only four days that the temperatures reached 90 . September was unseasonably warm with the average maximum temperatures some five degrees above the 12 year average. Of particular interest is the rainfall record. Total rainfall during the growing season was the second lowest since 1967 and 6.1 inches below the 12 year average. Only 0.04 inches were recorded in September which is the lowest recorded for any month during our tenure at this facility. It allowed for continuous plot harvest without interuption. Irrigation applications of slightly less than one inch each were made fourteen times (June 6, July 10, 13, 17, 20, 23, 27, 31, August 3, 7, 14, 21, 28, September 3, 8). SOIL TESTS Soil test results for the general plot area were: Pounds per Acre P pH 6.3 601 Pounds per Acre K 253 Pounds per Acre Pounds per Acre Ca 960 Mg. 137 Percent organic matter 2.6 Table 1. The 12 year summary of average maximum and minimum temperatures during the growing season at the Montcalm Branch Experiment Station. Year Apri l Max Apri l Min Ma Ma Jun y Max y Min e Max Jun e Min Jul y Max Jul y Min Augus t Max Augus t Min Septembe r Max Septembe r Min 6-mont h averag e max 6-mont haverage min 62 67 65 65 70 63 62 73 63 80 67 61 56 54 53 47 54 57 48 58 62 50 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 12-year average 54 50 74 70 72 81 72 77 73 75 79 76 78 41 43 47 39 47 42 41 48 41 47 45 37 50 35 49 35 45 31 48 30 48 36 51 36 48 28 49 35 48 37 50 31 49 33 66 44 74 558257 77 55 76 47 71 49 empty table cell 34 53 50 55 56 50 58 52 56 57 50 50 55 59 60 55 57 60 57 57 58 61 56 50 49 51 54 49 48 45 44 46 53 52 58 56 57 53 57 60 56 58 53 52 57 80 80 80 82 79 79 81 80 81 85 81 81 82 80 80 76 80 77 79 80 77 82 73 74 73 76 73 74 70 70 71 75 72 67 44 75 54 74 73 70 73 69 73 68 65 70 70 75 81 58 79 56 71 49 empty table cell Table 2. The 12-year summary of precipitation (inches per month) recorded during the growing season at the Montcalm Station. Year April May June July August September Total 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 12-year average 2.84 3.33 2.42 1.59 1.35 3.25 4.07 1.81 3.27 1.65 2.34 2.58 2.54 4.90 3.65 4.09 0.93 1.96 3.91 4.83 2.05 4.03 0.46 1.35 1.68 2.82 3.74 6.18 4.62 1.50 2.51 4.34 4.69 4.98 4.22 1.66 2.55 3.77 3.73 1.23 2.63 3.67 1.22 3.83 2.36 2.39 2.71 1.50 2.39 1.89 1.09 2.24 1.31 1.79 6.54 2.67 7.28 3.94 6.18 11.25 1.44 2.61 5.90 3.69 4.55 3.30 0.58 7.18 4.00 2.60 1.33 1.81 3.07 1.40 8.62 2.77 0.04 3.06 17.32 13.16 28.52 11.91 19.53 19.13 23.97 25.87 15.86 17.39 16.80 12.85 18.94 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: - 0-0-60 - 200 lbs/A Plow down - 20-10-10 - 600 lbs/A Banded at planting Sidedressed at hilling - 46-0-0 - 300 lbs/A Alfalfa cover crop plowed down. Herbicides Preplant incorporated EPTC (Eptam) 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 13 July 20 July 28 August 3 August 11 August 20 August 28 Sept. 7 Bravo Monitor + Bravo Monitor + Bravo Thiodan + Bravo Thiodan + Bravo Thiodan + Bravo Thiodan + Bravo Thiodan + Bravo Top killed prior to harvest with Dinoseb (Dow General) two quart/A plus crop oil concentrate (Herbimax) at one quart/A. 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 phosphorus levels and their interaction with selected insect and nematode control programs and to monitor growth and development and yield. Seedpieces were planted on May 16-17, 1979 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 various 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. Sool 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 (cv Superior) were planted in plots treated with two levels of phosphorus (50, 150 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. (15-20cp) soil depth on May 1, 1979. Those plots to receive phosphorus were applied with either 50 lbs/acre or 150 lbs/acre P2O5 at planting. All plots also received a uniform application of 500 lbs/acre NPP(22-0-0) at planting. The plots were hilled and sidedressed at an education rate of 145 lbs/acre Urea (45%) on June 20, 1979. Phosphorus application rate and nematicide treatment contributed significantly to final yield. Irrespective of the pesticide used, yields were higher at the higher phosphorus application rate (Table 1). Within each phosphorus level, total yields increased consistantly from the controls, to the Temik and Vorlex treated plots, respectively. The total yield of plots treated with Vorlex were significantly higher (P = 0.05) than the controls at the 0 lb/acre and 50 lb/acre phosphorus rates. Highest total yields were observed in the 150 lb/acre phosphorus plots with Temik 15G and Vorlex. Yields of A grade potatoes showed similar results to that of total yield (Table 1). No significant differences in yields of B grade potatoes were observed. Yields of the oversized 'Jumbo' grade potatoes increased with increasing phosphorus application rate in the controls and Temik treated plots. Both Temik 15G at the 150 lb/acre phosphorus rate and Vorlex at the 50 lb/acre and 150 lb/acre phosphorus rates, significantly increased yields over the controls and the 0 lb/acre phosphorus plots. The control at the 150 lb/acre phosphorus rate and Vorlex at the two highest phosphorus rates significantly (P = 0.05) increased the specific gravity of potatoes over the Temik 15G plots at the 50 lb/acre phosphorus rate (Table 11). There were no significant differences in soil population densities of Pratylenchus penetrans among the plots except for the sample of June 26, 1979 (Table 2). Temik 15G significantly reduced the soil population density of P. penetrans over the control and Vorlex treatments in the 0 lb/acre phosphorus plots. There were no significant differences in root population densities of P. penetrans among the plots season long (Table 3). Based on P. penetrans recovered from root tissue in this test, Temik 15G resulted in the best nematode control. There were no significant differences in root weight, tuber weight, plant weight or tuber number among the treatments season long, (Tables 5, 8, 9, 10, respectively). The effect of varing phosphorus levels and nematicide treatment on stem weight and foliage weight is reported in Tables Six and Seven. Experiment II Seedpieces (cv Ruuset Burbank) were planted in plots treated with two levels of phosphorus (50-150 lbs/acre) and two nematicide treatments (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. (15-20cm) soil depth on May 1, 1979. Those plots to receive phosphorus were applied with either 50 lbs/acre or 150 lbs/acre P2O5 at planting. All plots also received a uniform application of 500 lbs/acre NPK (20-0-0) at planting. The plots were hilled and sidedressed at an application rate of 145 lbs/acre Urea(45%) on June 20, 1979. Phosphorus application rate and nematicide treatment contributed significantly (P = 0.05) to the final yield (Table 12). Irrespective of the pesticide used, yields were generally higher at the higher phosphorus rate. Vorlex at the two highest phosphorus rates significantly (P = 0.05) increased total yield when compared to the controls at the 0 lb/acre and 50 lb/acre phosphorus rate and the 0 lb/acre Temik 15G plots. Yield of Jumbo grade potatoes increased with increasing phosphorus, and was highest in the Vorlex treated plots (Table 12). Within each phosphorus level, yields increased consistantly from the controls to the Temik and Vorlex treated plots, .respectively. Vorlex at the 150 lb/acre phosphorus level significantly(P = 0.05) increased the yield of Jumbo grade potatoes. The yield of B grade potatoes was significantly (P = 0.05) greater in the 50 lb/acre phosphorus control plots than in the control plots at the lower phosphorus level (Table 12). Irrespective of the phosphorus application rate, yield of A grade potatoes were highest in the Vorlex treated plots (Table 12). Yield of A grade potatoes was significantly (P = 0.05) increased with Vorlex at phosphorus rates above 50 lb/acre over the control and Temik 15G plots at 0 lb/acre. The yield of Knob grade potatoes generally increased with increasing phosphorus and were highest in the Temik 15G and Vorlex treated plots (Table 12). Yields of Knob grade potatoes were significantly (P = 0.05) increased by Temik 15G, at the 150 lb/acre phosphorus rate. Vorlex at the 150 lb/acre phosphorus rate significantly (P = 0.05) increased the specific gravity of cv Russet Burbank potatoes (Table 11). Irrespective of the phosphorus level, soil population levels of P. penetrans were consistantly lower in the Temik 15G plots season long (Table 13). During the June 26, 1979 sample, Temik 15G significantly (P - 0.05) reduced soil population densities of P. penetrans at all phosphorus rates when compared to the control plot at the 150 lb/acre phosphorus rate. 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 root weight, tuber weight or tuber number season long (Table 16, Table 19, Table 20, respectively). From June 26, 1979 plant weight were higher in all nematicide treatments (Table 21). Stem weight and foliage weight were generally higher at the higher phosphorus rate and in all the nematicide treatments (Table 17, Table 18, respectively). TABLE 1 Influence of selected management inputs on the yield and grade of potatoes (cv Superior) YIELD (CTW/ACRE) YIELD (CTW/ACRE) TREATMENT 0P2 Check YIELD (CTW/ACRE) A B Grade 215.0a1 0P Temik 15G 3 lb a.i./acre 247.5ab 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre 277.5bc 247.7ab 276.8bc 298.1c 282.7bc 315.7c 324.6c Grade 10.9a 13.2a 14.9a 10.5a 11.2a 12.7a 11.6a 11.9a 12.3a Jumbo Grade 10.5a 20.0ab YIELD (CTW/ACRE) Total 236.7a 280.7ab 22.6abc 314.9bc 15.0ab 273.3ab 28.7bcd 316.7bc 38.1d 19.4ab 36.4cd 29.9bcd 348.9c 313.7bc 364.1c 366.7c 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 0P = 0 lb. phosphorous per acre 2 TABLE 2 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT 0P2 Check P. penetrans per 100 cm3 soil 5/01/79 28a1 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre 30a 35a 42a 23a 30a 55a 42a 32a P. penetrans per 100 cm3 soil P. penetrans per 100 P. penetrans per 100 cm3 soil cm3 soil P. penetrans per 100 cm3 soil 5/16/79 6/04/79 6/26/79 41a 36a 30a 39a 24a 16a 50a 37a 14a 20a 17a 16a 20a 9a 18a 19a 12a 14a 19b 2a 15b 12ab 3a 8ab 20b 2a 10ab 7/23/79 78a 85a 79a 120a 23a 12a 80a 25a 119a P. penetrans per 100 cm3 soil 8/21/79 39a 2a 39a 55a 4a 53a 40a 8a 41a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 3 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre P. penetrans per gram root tissue P. penetrans per gram root tissue 6/04/79 6/26/79 P. penetrans per gram root tissue 7/23/79 P. penetrans per gram root tissue 8/21/79 19a1 3a 15a 19a 7a 16a 25a 3a 9a 56a 11a 20a 24a 14a 17a 36a 11a 19a 178a 6a 206a 205a 6a 149a 175a 9a 173a 95a 6a 74a 182a 25a 151a . 214a 6a 148a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 4 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 1b a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre P. penetrans per 100 cm3 soil and per gram root tissue combined6/04/79 40a 20a 32a 39a 17a 35a 44a 15a 24a P. penetrans per 100 cm3 soil and per gram root tissue combined 6/26/79 P. penetrans per 100 cm3 soil and per gram root tissue P. penetrans per 100 cm3 soil and per gram root combined 7/23/79 tissue combined 8/21/79 76b 13a 36ab 37ab 17a 25ab 57ab 14a 30ab 256bc 91ab 285bc 326c 92ab 162abc 255bc 35a 293bc 134a 9a 113a 237a 29a 204a 254a 14a 189a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 0P = 0 lb. phosphorous per acre . 2 TABLE 5 Influence of selected management inputs on root weight of potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre ROOT WEIGHT (GRAMS)6/04/79 ROOT WEIGHT (GRAMS) 6/26/79 ROOT WEIGHT ROOT WEIGHT (GRAMS) 8/21/79 (GRAMS) 7/23/79 3.6a1 3.8a 3.4a 4.3a 3.0a 3.2a 3.6a 4.2a 3.3a 13.7a 13.6a 15.0a 13.6a 12.2a 15.4a 14.2a 15.8a 13.7a 12.5a 11.8a 10.6a 13.4a 14.4a 12.3a 11.0a 13.4a 13.0a 9.3a 11.0a 8.9a 14.7a 7.7a 6.9a 8.5a 5.5a 7.6a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 6. Influence of selected management inputs on stem weight of potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre STEM WEIGHT (GRAMS) 6/26/79 STEM WEIGHT (GRAMS) 7/23/79 STEM WEIGHT (GRAMS) 8/21/79 STEM WEIGHT (GRAMS) 6/04/79 01 0 0 0 0 0 0 0 0 45.5a 43.7a 47.3a 36.9a 43.0a 35.4a 46.0a 48.0a 38.8a 28.9ab 22.9a 27.9ab 39.1b 37.2ab 31.5ab 26.5ab 33.9ab 32.9ab 8.1a 11.4a 10.2a 8.6a 6.9a 8.2a 10.8a 12.0a 12.5a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P 0 lb. phosphorous per acre TABLE 7 Influence of selected management inputs on foliage weight of potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre FOLIAGE WEIGHT FOLIAGE WEIGHT (GRAMS) 6/04/79 (GRAMS) 6/26/79 FOLIAGE WEIGHT (GRAMS) 8/21/79 23.4a1 26.8a 20.8a 23.9a 20.0a 20.5a 23.1a 22.8a 23.4a 216.1a 249.9a 278.3ab 274.2ab 263.8ab 400.1b 297.2ab 397.6b 383.0b 22.4a 65.6a 39.8a 42.2a 34.2a 40.7a 49.3a 74.0a 76.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 8 Influence of selected management inputs on tuber weight of potatoes (cv Supprior) TUBER WEIGHT/PLANT TUBER WEIGHT/PLANT TUBER WEIGHT/PLANT TREATMENT 0P2 Check (GRAMS) 6/26/79 45.71a1 0P Temik 15G 3 lb a.i./acre 24.07a 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre 22.22a 21.04a 21.56a 21.15a 25.47a 21.77a 24.33a (GRAMS) 7/23/79 524.11a 532.21a 757.92a 501.91a 772.13a 803.25a 588.47a 742.75a 813.26a (GRAMS) 8/21/79 651.87a 822.17a 690.80a 796.36a 734.07a 822.95a 818.77a 837.25a 934.57a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 9 Influence of selected management inputs on tuber number of potatoes (cv Superior) TUBER NUMBER/PLANT (GRAMS) TUBER NUMBER/PLANT (GRAMS) TUBER NUMBER/PLANT (GRAMS) TUBER NUMBER/PLANT (GRAMS) TREATMENT 0P2 Check 0P Temik 15G 3.lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb /.i./acre 150P Vorlex 10 gal/acre 6/04/79 6/26/79 7/23/79 8/21/79 01 0 0 0 0 0 0 0 0 13.4a 10.6a 14.8a 9.2a 11.2a 13.4a 9.8a 14.0a 7.8a 11.2a 8.0a 11.2a 12.0a 13.4a 14.0a 9.2a 12.4a 12.8a 7.0a 9.2a 7.8a 9.4a 7.4a 9.0a 8.6a 7.8a 8.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 0P = 0 lb. phosphorous per acre 2 TABLE 10 Influence of selected management inputs on plant weight of potatoes (cv Superior) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre PLANT WEIGHT (GRAMS) PLANT WEIGHT (GRAMS) PLANT WEIGHT (GRAMS) PLANT WEIGHT (GRAMS) 6/04/79 6/26/79 7/23/79 8/21/79 27.0a1 30.5a 24.2a 28.2a 23.0a 23.8a 26.7a 27.0a 26.7a 321.0a 331.3a 362.8a 345.8a 340.5a 472.0a 382.8a 483.1a 459.8a 613.5a 655.2a 796.4a 554.4a 823.8a 847.0a 625.9a 790.la 859.2a 691.7a 910.2a 749.7a 861.7a 782.8a 878.8a 887.3a 928.8a 1030.7a 1 (P = Column followed by the same letter are not significantly different 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 2 0P = 0 lb phosphorous per acre TABLE 11 Influence of selected management inputs on specific gravity of potatoes TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre GRAVITY SPECIFIC SPECIFIC GRAVITY Russet Burbank 1.068a1 1.070a 1.072a 1.069a 1.070a 1.072a 1.072a 1.072a 1.077b Superior 1.066ab 1.066ab 1.067ab 1.066ab 1.065a 1.068b 1.068b 1.066ab 1.068b 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans- Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre . TABLE 12 Influence of selected management inputs on the yield and grade of potatoes (cv Russet Burbank) YIELD (CWT/ACRE) YIELD (CWT/ACRE) YIELD (CWT/ACRE) TREATMENT 0P2 Check 0P Temik 15G 3 1b a.i./acre 0P Vorlex 10 gal/acre 50P Check YIELD (CWT/ACRE)A Grade 182.9a1 196.2ab 248.8bc B Grade 22.5a 24.5ab 24.2ab 214.5abc 31.3b 50P Temik 15G 3 1b a.i./acre 217.9abc 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 1b a.i./acre 150P Vorlex 10 gal/acre 270.3c 253.6bc 209.7ab 267.4c 23.3ab 26.8ab 29.8ab 25.3ab 25.3ab Jumbo Grade 2.2a 3.4ab 5.6ab 7.4ab 7.6ab 11.6b 8.4ab Knobs 24.3a 44.3bc 31.2ab 26.7ab 52.2c YIELD (CWT/ACRE) Total 231.9a 268.5ab 309.7bc 279.9b 301.0bC 38.0abc 346.7c 30.9ab 10.4ab 64.8d 18.9c 30.9ab 322.6bc 310.2bc 342.4c 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 13 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Russet Burbank) TREATMENT 0P2 Check P. penetrans per 100 cm3 soil6/04/79 P. penetrans per 100 cm3 soil 6/26/79 P. penetrans per 100 cm3 soil 7/23/79 P. penetrans per 100 cm3 soil 9/05/79 14.6a1 15.6ab 40.2a 57.0bc 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre 5.4a 12.8a 12.0a 4.2a 9.8a 11.2a 5.8a 14.0a 5.8a 11.4ab 13,4ab 5.0a 12.6ab 19.8b 4.8a 12.8ab 6.0a 37.6a 37.0a 23.8a 11.8a 20.4a 10.8a 15.4a 2.0a 45.2abc 32.8abc 1.6a 32.8abc 75.4c 9.8ab 43.2abc 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 14 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Russet Burbank) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre P. penetras per gram root tissue6/04/79 16.6a1 2.2a 38.0a 12.6a 4.2a 22.8a 18.2a 2.8a 15.0a P. penetras per gram root tissue 6/26/79 P. penetras per gram root tissue 7/23/79 P. penetras per gram root tissue 9/05/79 47.0ab 10.6a 40.4ab 65.4b 2.8a 29.0ab 22.0ab 8.6a 43.8ab 59.0a 3.0a 64.8a 54.4a 0.8a 49.0a 49.6a 8.4a 58.0a 96.4ab 5.0a 134.8b 67.0ab 1.6a 94.6ab 85.4ab 4.0a 109.0b 1 Column followed by the same letter are not significantly different 2 (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. OP = 0 lb. phosphorous per acre . TABLE 15 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Russet Burbank) P. penetrans per 100 cm3 soil and per gram root tissue comined6/04/79 P. penetrans per 100 cm3 soil and per gram root tissue comined6/26/79 P. penetrans per 100 cm3 soil and per gram root tissue P. penetrans per 100 cm3 soil and per gram root tissue comined9/05/79 51.8ab 102.4a TREATMENT 0P Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 31.23b1 7.6a 50.8a 24.6ab 50P Temik 15G 3 lb a.i./acre 8.4a 50P Vorlex 10 gal/acre 150P Check 32.6ab 29.4ab 150P Temik 15G 3 lb a.i./acre 8.6a 62.6ab 16.4a 78.8b 7.8a 41.6ab 43.4ab 13.4a comined7/23/79 99.2a 9.0a 91.4a 24.6a 60.8a 70.0a 19.2a 73.4a 153.4b 7.0a 176.0b 99.8b 3.2a 127.4b 160.8b 13.8a 152.2b 150P Vorlex 10 gal/acre 29.0ab 56.6ab 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 16 Influence of selected management inputs on root weight of potatoes (cv Russet Burbank) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre ROOT ROOT WEIGHT (GRAMS) ROOT WEIGHT ROOT WEIGHT WEIGHT (GRAMS)6/04/79 6/26/79 (GRAMS) 7/23/79 (GRAMS) 9/05/79 2.6a1 2.la 2.0a 1.8a 1.6a 2.1a 1.7a 2.4a 2.2a 14.8a 19.6a 18.6a 13.8a 17.3a 20.5a 18.5a 16.5a 19.4a 18.4a 19.2a 19.0a 20.6a 20.6a 18.0a 13.3a 20.7a 23.3a 16.7a 15.7a 17.4a 13.7a 21.0a 20.2a 16.6a 21.2a 20.4a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 17 Influence of selected management inputs on stem weight of potatoes (cv Russet Burbank) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre STEM WEIGHT (GRAMS) STEM WEIGHT (GRAMS) 6/04/79 6/26/79 STEM STEM WEIGHT (GRAMS)7/23/79 WEIGHT (GRAMS) 9/05/79 01 0 0 0 0 0 0 0 0 39.3a 34.6a 43.2a 32.9a 33.4a 46.2a 34.5a 27.3a 43.8a 28.9a 33.2a 32.2a 32.2a 33.6a 36.1a 35.4a 37.6a 44.9a 16.5a 21.4ab 23.7ab 23.lab 27.0ab 34.1b 25.4ab 27.0ab 35.6b 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre TABLE 18 Influence of selected management inputs on foliage weight of potatoes (cv Russet Burbank) FOLIAGE WEIGHT (GRAMS) FOLIAGE WEIGHT (GRAMS)6/04/79 TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre 8.8a1 7.3a 8.5a 7.3a 4.9a 6.8a 7.8a 7.7a 6.6a FOLIAGE WEIGHT (GRAMS) 7/23/79 FOLIAGE WEIGHT (GRAMS) 9/05/79 588.3a 91.4a 653.7ab 205.8ab 779.0ab 289.1abc 668.6ab 222.8ab 803.2ab 408.3abcd 980.8ab 561.1cd 780.7ab 512.6bcd 889.1ab 489.1bcd 6/26/79 185.5a 239.8ab 258.2ab 239.5ab 249.4ab 330.4c 250.1ab 259.7ab 300.4bc 1059.1b 677.3d 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 0P = 0 lb. phosphorous per acre . . 2 TABLE 19 Influence of selected management inputs on tuber weight of potatoes (cv Russet Burbank) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre TUBER TUBER WEIGHT/PLANT TUBER WEIGHT/PLANT TUBER WEIGHT/PLANT (GRAMS)6/04/79 (GRAMS) 6/26/79 (GRAMS) 7/23/79 WEIGHT/PLANT (GRAMS)9/05/79 01 0 0 0 0 0 0 0 0 1.5a 0.7a 2.7a 1.4a 1.7a 2.5a 0.3a 0.9a 0.7a 400.9a 453.7a 497.5a 400.7a 416.9a 548.3a 424.7a 464.8a 583.2a 822.1a 968.3a 1156.4a 1025.2a 1035.2a 1385.6a 1092.7a 1076.5a 1282.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre , TABLE 20 Influence of selected management inputs on tuber number of potatoes (cv Russet Burbank) TUBER TUBER NUMBER/PLANT TUBER NUMBER/PLANT TUBER TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre NUMBER/PLANT (GRAMS)6/04/79 (GRAMS) 6/26/79 (GRAMS) 7/23/79 NUMBER/PLANT (GRAMS)9/05/79 01 0 0 0 0 0 0 0 0 8.8a 4.8a 11.0a 6.4a 4.6a 6.2a 2.6a 3.2a 5.2a 14.0a 17. 0a 18.6a 20.0a 17.0a 24.0a 22.0a 19.8a 24.8a 12.0a 9.2a 14.0a 12.6a 11.0a 17.2a 11.0a 11.8a 15.4a 1 2 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. 0P = 0 lb. phosphorous per acre TABLE 21 Influence of selected management inputs on plant weight of potatoes (cv Russet Burbank) TREATMENT 0P2 Check 0P Temik 15G 3 lb a.i./acre 0P Vorlex 10 gal/acre 50P Check 50P Temik 15G 3 lb a.i./acre 50P Vorlex 10 gal/acre 150P Check 150P Temik 15G 3 lb a.i./acre 150P Vorlex 10 gal/acre PLANT PLANT WEIGHT PLANT PLANT WEIGHT (GRAMS)6/04/79 (GRAMS) 6/26/79 WEIGHT (GRAMS)7/23/79 WEIGHT (GRAMS)9/05/79 11.5a1 9.4a 10.5a 9.1a 6.5a 8.9a 9.5a 10.1a 8.8a 241.0a 294.7ab 322.7ab 292.6ab 301.9ab 399.6c 303.3ab 304. 3ab 364.3bc 1036.5a 1159.8a 1327.7a 1122.1a 1274.4a 1583.2a 1259.1a 1412.2a 1710.5a 946.6a 1211.1ab 1486.6ab 1284.8ab 1491.5ab 2001.0b 1647.3ab 1613.7ab 2015.2b 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newmans-Keuls Multiple Range Test. 2 0P = 0 lb. phosphorous per acre THE INFLUENCE OF SELECTED MANAGEMENT INPUTS ON NUTRIENT COMPOSITION OP POTATO PETIOLES Department of Crop and Soil Sciences ML. Vitosh The effect of phosphorus fertilizer and two nematicides on yield, quality and storability of potatoes was reported on by G.W. Bird, J. Noling, B. Cargill and H. S. Potter. The results here only include plant and soil analysis of the integrated project. The experiment was conducted at the Montcalm Research Farm with Russet Burbank and Superior. Phosphorus was applied at rates of 0, 50 and 150 lb. P2O5 per acre banded two inches to either side and two inches below the seed. Temik 15G was applied with the banded fertilizer at a rate of three lb active ingredient per acre. Vorlex was applied two weeks prior to planting in a band 6-8 inches beneath the intended row at a rate of 10 gal. per acre. All plots received a uniform application of nitrogen and potassium. In the previous report both rates of P and the nematicides significantly increased the total yield of both varieties. Soil test values from the treated plots are shown in Tables 1 and 2. Good uniformity was observed for all treatments as indicated by the non-significant (NS) LSD tests. Soil P levels for the Research Farm are extremely high and potassium values are considered to be medium. Potato petiole samples were taken on July 5th and then two weeks later on July 19. Analysis for the first sampling are shown in Tables 3 and 4. Only P and Manganese (Mn) were significantly affected by the treatments for the Russet Burbank variety. Phosphorus in petioles was directly related to rate of P application. Manganese was significantly reduced by Vorlex at all P rates. Temik also tended to reduce the Mn content but the reduction was not significant. Similar reductions in Mn content have been observed for the past three years. We are still unable to explain the change in Mn uptake or how it might be related to yield increases from Temik or Vorlex. Similar results for P and Mn are observed for Superior (Table 4). In add­ ition calcium (Ca) and sodium (Na) were significantly affected by the treatments for this variety. The differences however were not consistent and can not be explained at this time. For the second sampling on July 19, similar results for P and Mn were observed. In addition several other elements for Superior (Table 6) were significantly affected by the treatments. The differences again were not always consistent, however K, Ca, Fe, Cu and Zn values appeared to be lower with the higher rates of P. Many of the elements (P, K, Fe, Cu, Zn and Al) were found in smaaier quantities with the second sampling. Only Ca, Mg, Na and Mn were found to increase with the later sampling. Normal or sufficient ranges for petioles from recently matured leaves sampled in mid-season have been reported as follows: P .18 - .22 K 6.0 - 9.0 Ca .36 - .50 Mg .17 - .22 Mn 30 - 200 Fe 30+ B 14 - 40 Cu 7 - 30 Zn 30 - 100 From these sufficiency ranges it would appear that all elements were in sufficient supply at the time of the July Sth sampling even in the OP check treatment. On July 19, P levels had dropped below the .18 critical level for nearly all treatments on Supprior but only the OP, check treat­ ment on Russet Burbank. I conclude that July 19 was too late for the Superior variety in order to utilize the established sufficiency ranges. Copper (Cu) and zinc (Zn) also appeared to be below the sufficiency range on July 19. In summary it appears that for samples taken 30-40 days after emergence, the petiole P content should be above .3% for Superior and .4% for Russet Burbank. Phosphorus values below these levels at this stage of growth will result in less than optimum yield. In regard to manganese it appears that Vorlex and to a lesser extent Temik, do alter the uptake of Mn while increas­ ing yield. This cannot be explained by the dilution effect due to more growth because none of the other elements changed. Manganese is known to affect certain enzyme reactions. It may be that a reduction in Mn allows for more production of some growth regulator which results in greater growth and yield. Some very basic biochemistry research will be necessary to prove this theory. The soil tests for P indicates extremely high levels (above 400 lb/A) and yet very significant increases in yield occurred. This data leaves much doubt in the reliability of the Bray P1 phosphorus test to predict P re­ quirements for potatoes. For corn, 5O to 60 lb P/A soil test is generally adequate for maximum production. Why the potato plant cannot adequately utilize soil P measured by the Bray P1 test is a mystery at this time. Addit­ ional basic research will be needed to answer this question. Table 1. Soil Test values on samples taken from treated plots in June 1979. (Range 4). Treatment 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik 150P Vorlex Soil TestspH 5.3 5.4 5.4 5.4 5.4 5.4 5.2 5.3 5.3 Soil TestsP Soil Tests K Soil lb/A lb/A Tests Ca lb/A Soil Tests Mn lb/A 473 462 456 487 457 461 499 480 484 395 398 362 389 419 373 395 386 376 768 768 789 725 811 725 747 725 853 124 124 132 107 128 113 107 98 111 LSD (.05) (NS) (NS) (NS) (NS) (NS) Table 2. Soil test values on samples taken from treated plots in June 1979. (Range 5). Soil Tests K Soil Soil TestsP lb/A lb/A Tests Ca lb/A Soil TestsMn lb/A 158 136 162 131 169 167 159 136 187 (NS) 1006 960 1143 937 1051 1052 1028 960 1157 (NS) Treatment 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik Soil TestspH 5.8 5.8 5.9 5.6 6.1 6.0 6.0 5.7 150P Vorlex 6.0 456 431 470 453 460 448 468 481 497 341 323 378 348 345 310 343 353 375 LSD (.05) (NS) (NS) (NS) Table 3. Elemental composition of Russet Burbank petioles sampled July 5, 1979 as affected by phosphorus and nematicide treatments. Treatments 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik 150P Vorlex Element s P % Element s K % .25 .27 .28 .38 .39 .39 .45 .43 .47 10.6 10.5 10.5 10.4 10.2 10.5 10.3 10.7 10.5 ElementsCa % .61 .59 .55 .47 .48 .50 .54 .58 .53 ElementsMg % .39 .38 .38 .31 .33 .37 .32 .34 .37 Elements Mn ppm 119 103 63 135 119 79 151 143 84 ElementsNa ppm 74 91 84 128 95 70 79 60 80 ElementsFe ppm 77 96 83 93 92 69 77 77 84 Element s B ppm 25 24 23 25 22 23 21 22 23 ElementsCu ppm 9 10 9 9 9 9 8 9 9 ElementsZn ppm 46 46 49 48 48 46 44 44 47 ElementsAl ppm 61 72 59 63 65 45 58 56 51 LSD (.05) (.04) (NS) (NS) (NS) (NS) (24) (NS) (NS) (NS) (NS) (NS) Table 4. Elemental composition of Superior potato petioles sampled July 5, 1979 as affected by phosphorus and nematicide treatments. Treatments 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik 150P Vorlex .19 .25 .22 .32 .27 .34 .39 .45 .39 11.2 11.8 11.9 11.3 12.1 12.2 11.7 11.7 11.8 (NS) LSD (.05) (.04) (.11) (NS) (41) (31) (NS) (NS) (NS) (NS) (NS) Element s P % Element Element s K % s Ca % Element sMg % ElementsNa ppm 39 63 49 74 52 112 82 67 57 Elements Na ppm 116 101 76 133 120 70 120 123 83 ElementsFe ppm 98 84 104 92 79 90 92 81 90 ElementsB ppm 28 27 27 26 26 26 25 25 26 ElementsCu ppm 10 10 12 10 10 11 9 10 10 ElementsZn ppm 32 38 43 35 37 39 34 41 33 ElementsAl ppm 82 62 68 71 56 61 57 54 56 .80 .65 .76 .61 .73 .64 .71 .69 .72 .42 .34 .40 .32 .42 .39 .36 .36 .44 Table 5. Elemental composition of Russet Burbank petioles sampled July 19, 1979 as affected by phosphorus and nematicide treatments. Treatments 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik 150P Vorlex ElementsP % ElementsK % Element s Ca % .18 .20 .21 .21 .24 .25 .27 .25 .32 10.0 10.0 9.5 10.4 10.2 9.9 10.1 10.1 9.8 .78 .76 .70 .78 .72 .66 .79 .86 .70 ElementsMg % ElementsNa ppm Elements Mn ppm Element .55 .56 .56 .54 .53 .55 .53 .56 .52 111 117 104 93 71 104 64 64 90 148 125 96 277 206 125 284 249 147 sFeppm 48 38 40 39 39 56 37 39 40 Element s B ppm 27 26 25 27 26 26 26 26 25 ElementsCu ppm 6 7 7 5 6 6 5 5 6 ElementsZn ppm 35 36 31 39 35 34 32 32 35 ElementsAl ppm 20 17 16 18 15 17 15 15 14 LSD (.05) (.06) (NS) (NS) (NS) (NS) (59) (NS) (NS) (NS) (NS) (NS) Table 6. Elemental composition of Superior potato petioles sampled July 19, 1979 as affected by phosphorus and nematicide treatments. Treatment 0P Check 0P Temik 0P Vorlex 50P Check 50P Temik 50P Vorlex 150P Check 150P Temik 150P Vorlex ElementsP % Element ElementsCa % ElementsMg % ElementsNa ppm Elements Mn ppm s K % 9.9 1.07 10.2 10.0 9.8 9.4 9.2 9.7 9.3 8.8 .99 1.06 .92 .91 .91 1.02 .89 .95 .12 .13 .13 .14 .13 .13 .14 .18 .16 .75 .59 .77 .50 .67 .66 .64 .52 .68 129 106 95 105 70 86 88 105 90 209 184 129 281 201 155 244 214 162 ElementsFe ppm 53 50 60 47 47 51 49 49 49 ElementsCu ppm Element s B ppm 30 29 29 30 27 28 29 28 29 6 7 7 4 5 5 3 6 4 ElementsZn ppm 32 31 31 25 25 23 19 23 22 ElementsAl ppm 53 42 46 45 50 41 42 39 42 LSD (.05) (.02) ( .8) (.13) (NS) (NS) (53) (6) (NS) (2) (9) (NS) INFLUENCE OF PRE-STORAGE TREATMENTS ON OUT-OF-STORAGE QUALITY Department of Agricultural Engineering B.F. Cargill * introduction This report includes the results of two 1978 potato storage projects. The 1979 potatoes are still in storage and will be reported in the 1980 report. OBJECTIVES The 1978 Integrated Project (storage phase) 1. To study the influence of selected production management inputs on storability by determining weight loss, tuber quality and seed viability after extended storage. The 1978 Harvesting Storage Project (#8) 1. To study the influence of post harvest pre-storage mechanical and chemical treatments on storability by determining tuber quality, chip quality, and weight loss. 2. To compare the storability of equivalent pre-storage treated Monona potatoes stored in MSU cubicles and a commercial bulk storage. OVERALL PROCEDURE This report includes: 1) the Storage Phase of the 1978 MSU Integrated Project; it involves storage of Superior potatoes grown using various levels of nitrogen and different insecticides. Respective bagged lots of Superior potatoes wore stored in the MSU cubicles to evaluate the effects of production practices and storage: on seed viability; weight loss in storage; tuber quality after storage; and chip quality after storage; & 2) the 1978 MSU Harvesting and Storage Project #8; this project involved an evaluation of post harvest pre-storage treatments (mechanical and chemical) on the out-of-storage qulity of Monona potatoes. Specific Procedure for 1978 Superior Potatoes Superior potatoes (1978) were planted for the Integrated Project at the Montcalm Potato Research Farm, Superior potatoes were planted in two ranges (Range 7 § 8) and subjected to three levels of nitrogen and two insecticides in Range 7 and two levels of nitrogen and four insecticides in Range 8. These Superior potatoes were mechanically harvested using the MSU plot harvester; placed in mesh bags; and stored at two environments (40° & 50°F & 95% RH. At prearranged times during the storage period bagged lots of these Superior potatoes were removed from storage and evaluated for weight loss, tuber quality and chip quality. At planting time in May 1979 one bagged lot (nine treatments and five replications and ten treatments and five replications - 95 bags) was removed and 65 tubers were planted from each bag to study seed viability due to production practices and storage. *Other Investigators on this storage project: Dr. H.S. Potter, Botany & Plant Pathology Dr. J.N. Cash, Food Science & Human Nutrition Dr. Richard Chase, Crop & Soil Sciences Specific Procedure for 1978 Monona (One range (area) at the Mootcalm Potato Research Farm was used for Monona potatoes specifically grown for the MSU Storage Research Project. These potatoes were grown using one of the recommended production practices of the Integrated (Range 7 150 lb N & Temik). This same practice was used for 1977 potatoes and will also be repeated for 1979 potatoes. This production/storage project will be repeated for four years to exclude the production environment variable and its potential influence on storability. These Monona potatoes were mechanically harvested with the MSU plot harvester. Some lots were subjected to additional controlled bruising and prestorage treated with bactericide and fungicide chemicals. Bagged lots of bruised and nonbruised, treated and non-treated potatoes were stored in cubicles at MSU and in the center of a bulk bin in a commercial potato storage. The potatoes in the MSU cubicles were examined at a predetermined schedule for tuber quality, weight loss, and chip quality. Potatoes stored in the bulk bin were examined when the bin was emptied. Results & Discussion (Superior Potatoes) The 1978 Integrated Experiment I Range 7 (nine treatments) Superior potatoes were planted in plots treated with three levels of nitrogen (75-150-300 lb/acre) and three insecticide/nematicides (Temik 3.0 lb a.i./acre, Vorlex 10 gal/acre and a check). Each treatment was replicated five times. All plots received a uniform application of NPK at planting and the added nitrogen variables were side dressed later. Vorlex was applied two weeks before planting, and Temik was applied at planting. All plots were sprayed (as needed) with foliar insecticides. The potatoes were machine harvested with the MSU plot harvester and stored in the MSU cubicles to evaluate weight loss, tuber quality, chip quality, and seed viability. Experiment II Range 8 (ten treatments) Superior potatoes were planted to evaluate the interaction of two levels of nitrogen (75 and 150 lbs/acre) with five nematicide/insecticide treatments. (Temik 3.0 lb a.i./acre, Furadan 3.0 lb a.i./acre, Dacamox 3.0 lb/acre, Vorlex 10 gal/acre and an untreated check). The treatments were replicated five times. The potatoes were machine harvested with the MSU plot harvester and stored in the MSU cubicles to evaluate weight loss, tuber and chip quality and seed viability. Table I. Total weight loss of 1978 Superior potatoes * grown using nine different production treatments and stored for 9 months at 40°F and 95% RH. Treatment Replications and Average IV Replications and Average Replications and Average I Weight Loss % Weight Loss % Weight Loss % III II Replications and Average Weight Loss % Rank due to Weight Loss Ave. Weight Loss % Replications and Average V Weight Loss % 75 N Check 1 75 N Temik 2 75 N Vorlex 3 4 150 N Check 5 150 N Temik 6 150 N Vorlex 7 300 N Check 8 300 N Temik 9 300 N Vorlex 5.73 7.54 5.21 6.05 6.48 7.39 11.18 5.61 7.24 6.07 6.77 7.01 6.43 6.55 6.36 6.55 8.87 6.28 6.81 6.49 7.14 6.91 7.45 6.61 5.92 7.18 6.56 6.67 5.73 5.98 5.34 5.84 6.95 5.43 6.23 5.86 5.33 7.23 7.34 5.02 5.69 6.08 6.23 7.09 8.28 6.06 1** 6.75 6.54 6.23 6.40 6.68 7.06 6.99 6.84 6 4** 2** 3** 5 9 8 7 Average empty table cell empty table cellempty table cellempty table cellempty table cell6.62 empty table cell *Weighed at harvest August 22, 1978 and May 14, 1979 **Top four (4) in rank of least weight loss in storage Table II. Total weight loss of 1978 Superior potatoes* grown using ten different production treatments and stored for 9 months at 40°F and 95% RH. Treatment Replications and Average Replications and Average Replications and Average Replications and Average I Weight Loss % Weight Loss % II III Weight Loss % IV Weight Loss % Rank due to Weight Loss V Weight Loss % Replications and Average Ave. Weight Loss % 5.09 1 75 N Check 3.80 75 N Temik 2 5.19 75 N Vorlex 3 75 N Furadan 5.31 4 75 N Dacamox 4.41 5 9.09 6 150 N Check 3.92 7 150 N Temik 6.67 8 150 N Vorlex 9 150 N Furadan 4.14 5.64 10 150 N Dacamox empty table cell 6.03 6.16 5.21 5.43 7.02 5.11 6.09 8.06 4.66 6.18 5.50 5.62 5.94 5.34 5.73 6.62 5.79 6.35 5.36 5.10 empty table cellempty table cellempty table cellempty table cell5.73 3.90 5.08 5.58 4.76 5.38 6.19 6.88 4.43 5.24 4.19 5.13 6.78 7.30 5.93 6.06 5.93 5.36 5.91 5.42 4.27 7.35 6.28 6.41 5.26 5.78 6.76 6.69 6.67 7.33 5.21 Average 4** 5 8 2** 6 10 7 9 3** 1** empty table cell *Weighed at harvest August 22, 1978 and May 14, 1979 **Top four (4) in rank of least weight loss in storage Table III. Total weight loss of 1978 Superior potatoes grown using: two levels of nitrogen, two chemical treatments, and stored for 9 months at 40°F & 95% RH. Production Treatments Nitrogen level, lbs/A 75 N 150 N 75 N 75 N 150 N 150 N Storage Weight Loss, % Storage Weight Loss, % Storage Weight Loss, % Chemical Temik Vorlex Check Temik Vorlex Check Range 7 6.75 6.54 6.06 6.40 6.68 6.23 Range 8 5.62 5.94 5.50 5.79 6.35 6.62 Average 6.18 6.24 5.75 6.10 6.52 6.42 due to Rank Weight Loss 3 4 1 2 6 5 Table IV. Total weight loss of 1978 Superior potatoes: using three (3) levels of nitrogen and stored for 9 months at 40°F & 95% RH. Nitrogen level, Ibs/A 75 150 300 Storage Weight Loss, % Storage Weight Loss, % Range 7 6.45 6.44 6.96 Range 8 5.63 5.84 — Average 6.04 6.14 6.96 Rank due to Weight Loss 1 2 3 Table V. Tuber quality * production treatments and stored for 9 months at 40°F and 95% RH. of 1978 Superior potatoes grown using different Good Potatoes, % Replications and Average Good Potatoes, % Replications and Average Good Potatoes, %Replications and Average Good Potatoes, % Replications and Average V Potatoes, % Replications and Average Good I III II Production Treatments 1 75 N Check 75 N Temik 2 75 N Vorlex 3 4 150 N Check 5 150 N Temik 6 150 N Vorlex 7 300 N Check 8 300 N Temik 9 300 N Vorlex Average 95.9 96.2 96.2 96.0 93.6 90.1 96.9 86.1 89.9 93.4 96.3 75 N Check 1 92.2 2 75 N Temik 75 N Vorlex 3 95.3 75 N Furadan 93.4 4 75 N Decamox 93.5 5 93.8 6 150 N Check 7 150 N Temik 92.0 94.4 8 150 N Vorlex 9 150 N Furadan 96.8 10 150 N Dacamox 94.2 94.2 Average 95.4 95.6 97.3 99.1 95.6 91.9 84.5 88.0 93.9 93.5 96.2 89.5 88.1 90.5 95.6 96.4 93.8 86.2 93.4 92.1 92.2 98.0 97.1 97.0 95.7 96.3 95.1 92.9 93.2 93.6 95.4 94.2 94.7 95.1 96.2 95.6 96.1 91.2 94.0 95.8 91.4 94.4 IV 96.2 95.8 98.7 94.3 97.2 91.0 96.0 96.1 94.1 95.5 95.9 95.7 95.7 85.2 91.1 94.3 93.5 95.2 92.1 89.9 92.9 97.7 94.4 90.0 92.5 97.2 89.2 97.3 90.6 89.0 93.1 95.9 96.9 91.4 94.9 96.5 91.3 96.2 93.5 81.5 98.3 93.6 Rank based on Tuber Quality 1** 4** 3** 5 2** 8 6 9 7 empty table cell 1** 4** 7 9 2** 3** 5 8 10 6 empty table cell Ave. 96.6 95.8 95.8 95.5 96.0 91.5 93.5 90.8 92.1 94.2 95.7 93.8 93.1 92.0 94.5 94.4 93.3 92.7 91.9 93.2 93.5 *Marketable quality potatoes harvested August 22, 1978 with MSU plot harvester **Top four (4) in rank of best tuber quality out-of-storage Table VI. Comparison of yields of 1978 Superior potatoes grown using three (3) levels of nitrogen and two (2) chemical; stored for 9 months at 40°F and 95% RH; and planted as seed in 1979. 1978 Production Treatment and 1978 Production Treatment and 1978 Production Treatment 1979 1979 Seed Lot Yields Nitrogen Level Yields Chemical 1 2 3 4 5 6 7 8 9 75 lbs N 75 lbs N 75 lbs N 150 lbs N 150 lbs N 150 lbs N 300 lbs N 300 lbs N 300 lbs N Control Temik Vorlex Control Temik Vorlex Control Temik Vorlex and Yields 1978 Total Yield cwt/A 255 300 312 277 341 356 268 372 366 Yields Yield Difference 1979 vs. 1978 Marketable Potatoes cwt/A +48 -5 -6 +23 -91 -60 +22 -74 -77 271 265 278 279 232 271 262 273 261 Seed Yields Total cwt/A 303 295 306 300 250 296 290 298 289 *Difference in total yield in cwt/A between the 1978 production and the 1979 seed. These 1978 stored potatoes were planted May 6, 1979 and harvested August 22, 1979. Table VII. Comparison of total yield and marketable yield distribution of 1978 Superior potatoes grown using different production treatments; stored for 9 months at 40° and 98% RH; planted as seed May 6, 1979; and harvested August 22, 1979. 1978 Production Treatments Total cwt/A Mktb cwt/A % Under 2" 1 75 lb. Check 75 lb. Temik 2 75 lb. Vorlex 3 4 150 lb. Check 5 150 lb. Temik 6 150 lb. Vorlex 7 300 lb. Check 8 300 lb. Temik 9 300 lb. Vorlex 303 295 306 300 250 296 290 298 289 271 265 278 279 232 271 262 273 261 10.3 10.1 9.2 6.8 6.9 8.4 9.7 8.4 9.7 % Over 3 1/4" 4.1 11.1 7.7 2.1 9.4 5.8 7.0 5.2 14.1 *Number of plants per plot from 12 seed pieces **Top four (4) in rank of seed quality Rank of seed storability based on marketable production No. of Plants * Percent Virus 10.0 10.0 10.0 10.1 10.8 10.3 10.3 10.7 10.7 7.5 12.5 4.9 11.1 14.0 9.8 19.5 4.8 4.8 1** 5 6 2** 9 4** 7 3** 8 Table VIII. Coparison of yields of 1978 Supprior potatoes grown using two (2) levels of nitrogen and four (4) chemicals; stored for 9 months at 40° and 95% RH; and planted as seed in 1979. 1979 Seed 1979 Seed 1978 Production 1978 Production Treatments & 1978 Production Treatments & 1978 Treatments & Yields Treatment Number Yields Nitrogen Level Yields Chemical Production Treatments & Yields Total Yield 1978 cwt/A Yields Total cwt/A 1979 Yields Yield Difference * 1978 vs. 1979 Seed Yields Marketable Potatoes cwt/A 1 2 3 4 5 6 7 8 9 10 75 lb N 75 lb N 75 lb N 75 lb N 75 lb N 150 lb N 150 lb N 150 lb N 150 lb N 150 lb N Control Temik Vorlex Furadan Dacamox Control Temik Vorlex Furadan Dacamox 297 350 367 317 334 308 372 376 327 346 379 340 337 337 371 314 225 329 301 337 +82 -10 -30 +20 +37 +6 -147 -47 -26 -9 359 310 312 317 356 290 207 307 271 312 *Difference in total yield in cwt/A between the 1978 production and the 1979 seed. These 1978 stored potatoed were planted May 6, 1979 and harvested August 22, 1979. Table IX. Comparison of total yield and marketable yield distribution of 1978 Superior potatoes grown using different production treatments, stored for 9 months at 40°F and 95% RH; planted as seed May 6, 1979; and harvested August 22, 1979. 1978 Productions Treatment 1978 Productions Treatment 1978 1979 1979 Yield 1979 Yield s No. s N Level Production Treatments Chemical 1 2 3 4 5 6 7 8 9 10 75 lb. Check 75 lb. Temik 75 lb. Vorlex 75 lb. Furadan Dacamox 75 lb. 150 lb. Check 150 lb. Temik 150 lb. Vorlex 150 lb. Furadan 150 lb. Dacamox 1979 Yield Data Total Yield cwt/A Yield Data Mktb. Yield cwt/A Data Under 2" % Data Over 3 1/4" % 1979 Yield Data Specific Gravity 1979 Yield Data No. of Plants* 379 340 337 337 371 314 225 329 301 337 359 310 312 317 356 290 207 307 271 312 5.3 8.7 7.4 6.0 4.2 7.5 7.6 6.6 9.8 7.4 18.1 13.3 11.1 4.6 18.5 15.4 26.4 7.6 9.3 5.1 1.070 1.069 1.073 1.069 1.071 1.070 1.068 1.069 1.070 1.069 11.0 10.3 11.5 11.5 11.5 10.8 9.0 11.0 10.8 11.5 Rank Seed Storability Based on Marketable Production 1** 6 4** 3** 2** 8 10 7 9 5 *Number of plants per plot from 12 seed pieces. **Top four (4) in rank of 1978 seed viability in 1979 based on marketable production in 1979. Table X. Tuber quality of prestorage treated Monona potatoes stored in center of a bulk pile in a commercial potato storage for 9 months at approximately 45°F. TreatmentPotato Quality, % Good Non Bruised* No Chemical TBZ + Chi Non Bruised* TBZ only Non Bruised* Bruised (3x)* No Chemical TBZ + Chi Bruised (3x)* TBZ only Bruised (3x)* Bulk Storage 87.0 86.6 86.3 59.7 71.6 68.0 *Non bruised average 91.3% B.F. and bruised averaged 45.8% B.F. (bruise free) as evaluated by Ore-Ida, Greenville, Michigan. Table XI. Tuber quality after 9 months storage at 45°F of 1978 bruised and non-bruised Monona potatoes pre­ storage treated with TBZ and/or Chlorine*. 73.0 59.5 Replications & Potato Quality, Good Potatoes % 3 Replications & Potato Quality, Good Potatoes % 7 Replications & Potato Quality, Good Potatoes % 2 Treatment Replications & Potato Quality, Good Potatoes % 1 — 69.8 Bruised - no chemical 75.7 Bruised - TBZ Bruised - TBZ + Chl 81.4 Bruised - TBZ+Chl+Spr Ih 74.6 Non Bruised - no chem. Non Bruised - TBZ Non Bruised - TBZ+Chl Non Bruised - TBZ+Chl+ 59.5 66.7 70.0 77.2 76.5 67.2 70.8 74.6 73.5 74.0 87.5 92.2 85.2 87.5 86.0 95.9 87.1 70.8 92.6 87.2 77.8 67.1 60.8 76.1 83.1 83.6 94.9 92.5 87.9 93.6 90.4 95.7 91.7 89.8 89.0 91.0 85.2 86.9 90.1 85.3 Replications & Potato Quality, Good Potatoes % 5 Replications & Potato Quality, Good Potatoes % 9 Replications & Potato Quality, Good Potatoes % Replications & Potato Quality, Good Potatoes % 4 10 53.2 60.0 45.6 58.5 78.9 68.1 47.0 75.4 72.5 61.7 87.5 72.9 71.4 87.5 66.0 Replications & Potato Quality, Good Potatoes % Replications & Potato Quality, Good Potatoes % Replications & Potato Quality, Good Potatoes % 12 11 6 71.2 60.9 59.7 65.5 73.8 57.4 64.9 66.2 71.4 80.9 80.6 88.9 89.8 77.5 62.2 79.2 80.7 87.9 90.9 93.4 83.6 98.6 93.2 Replications & Potato Quality, Good Potatoes % Replications & Potato Quality, Good Potatoes % Average 8 57.1 48.4 59.7 68.0 71.6 73.1 87.0 86.3 86.6 88.3 83.1 83.8 78.1 88.1 91.3 93.2 77.5 87.5 87.5 Spr Ih Average of all bruised lots (45.8% B.F.) 68.1% good potatoes Average of all non-bruised lots (91.3% B.F.) = 87.1% good potatoes Average quality difference between bruised and non-bruised lots 19 % *Monona potatoes were hand picked out of a windrow (non-bruised) and rerun over a windrower three (3) times for a 3x bruise (bruised). Table XII. Weight loss after 9 months storage at 45°F 1978 bruised and non-bruised Monona potatoes pre­ storage treated with TBZ and/or Chlor *. ine Replication and Weight Loss % Replication and Weight Loss % Replication and Weight Loss % 9 5 1 Replication and Weight Loss % Replication and Weight Loss % Replication and Weight Loss % 11 7 3 Average Replication and Weight Loss % Replication and Weight Loss % Replication and Weight Loss % Replication and Weight Loss % 10 6 2 Replication and Weight Loss % Replication and Weight Loss % Replication and Weight Loss % 12 8 4 Treatment Braised - no chemical — 11.11 15.96 13.44 13.25 15.31 11.85 11.65 14.57 12.69 11.84 12.40 8.60 11.22 12.87 10.53 12.97 13.43 15.89 11.15 11.87 13.42 13.57 12.07 Bruised - TBZ 8.91 10.22 10.17 11.72 — 13.93 11.94 13.40 13.37 11.47 13.18 14.38 Bruised - TBZ+Chl 10.56 12.66 14.89 14.78 14.68 13.78 15.31 12.73 12.54 12.56 14.16 11.62 Bruised - TBZ+Chl+ Spr Ih Non-Bruised - no chem. 10.70 7.83 10.32 10.14 11.32 9.04 11.31 10.57 11.89 10.39 11.50 12.21 Non-Bruised - TBZ Non-Bruised - TBZ+Chl — Non-Bruised- TBZ+Chl+ 9.67 11.16 11.10 9.49 12.49 14.84 12.17 13.51 14.04 12.19 13.03 14.38 13.22 14.27 11.92 9.73 11.27 11.40 10.34 10.50 9.04 — 9.41 10.75 10.41 10.69 — 11.85 11.45 11.57 13.69 10.00 9.66 9.10 — Spr Ih *Monona potatoes were hand picked up from a windrow of potatoes (non-bruised 91.3% B.F.) and rerun over a windrower three (3) times for a 3x bruise (bruised 45.8% B.F.). 13.09 12.30 12.06 13.36 10.60 10.47 10.81 12.96 Table XIII. Dry rot infection and sprout inhibition after seven months storage at 40° and 50°F of Monona potatoes* prestorage treated with Roni lan. Storage Storage Temperature Storage Temperature 50ºF Temperature 40ºF Dry Rot, % 12.4 3.8 4.4 3.4 40ºF S.I** 3 1 1 1 Dry Rot, % 19.1 7.0 5.8 7.1 Storage Temperature50ºF S.I** 5 3 3 3 Treatment Water Ronilan 0.5 oz.a.i 1.0 oz.a.i Ronilan 2.0 oz.a.i Ronilan **S.I. (sprout index) 1 = 0 to less than 1/2" sprout 2 = 1/4 to 1" 3 = 1 to 2" 4 = 2 to 4" 5 = over 4" *mechanically bruised (3x) Publication Cargill, B.F. The Potato Storage proceedings of the 1980 Potato Growers Short Course, January 7-10, 1980. NEW VARIETY EVALUATION R.W. Chase, R.B. Kitchen, R.K. Peterson Dept. of Crop and Soil Sciences, Michigan State University Purpose: To determine the adaptation of new and existing potato cultivars to Michigan conditions. A. DATES of HARVEST (Montcalm Experimental Farm) Three blocks containing 104 ten foot plots were planted on May 2. Each block contained 26 cultivars and advanced selections planted in a randomized complete block design with four replications. One block was harvested on each of three dates: August 9; August 30; and September 24. At each date of harvest (D of H) , economic yields of table tubers (over 2 inches diameter), specific gravities, chip scores and internal evaluations (per 20 cut tubers) were determined for each of the 26 entries, Table 1. During the course of the growing season all plots received standard cultural practices. These included: 200 lbs./A 0-0-60 plow down, 3 lbs./A Eptam preplant incorporate; 600 lbs./A 20-10-10 and 20 lbs./A 15G Temik at time of planting; 0.5 lbs./A Sencor delayed preemerge; 300 lbs./A 46% urea sidedress; supplemental irrigation and application of Bravo 500, Monitor, and Thiodan as needed. Notes on each of the 26 entries appear below. Atlantic: USDA, Beltsville (1976); medium-late maturity; high (1.085-1.090) specific gravity; chips well; has above average yield potential; has low (10%) incidence of vascular discoloration, hollow heart and internal necrosis are major limitations. Belchip: USDD, Beltsville (1978); medium-late maturity; tubers flattened and somewhat rough; medium (1.075-1.080) specific gravity; chips well; average to above average yields; medium (20-30%) incidence of vascular discoloration this year. Belrus; USDA, Beltsville (1978); early dark russet type; medium specific gravity; acceptable chips; below average yields, did not bulk after first D of H; no internal defects. Very uniform type, appears best suited to early russet fresh market. Buckskin: Pennsylvania; medium-late maturity; medium specific gravity; acceptable chips; slightly below to below average yields in second and third D of H, significant bulking between first and second D of H; high (40%) incidence of vascular discoloration, some hollow heart and internal necrosis. Butte: USDA, Idaho (1977); late maturity russet; high specific gravity; average yields, tremendous bulking between first and second D of H; medium incidence of vascular discoloration. Appears to be later maturity in Michigan than is Russet Burbank. Croatan: North Carolina; medium maturity; low (1.060-1.065) specific gravity; acceptable chips; early bulking leads to significantly above average yields in first D of H, average to above average yields in later harvests; low incidence of vascular discoloration. Denali: Alaska, USDA (1979); medium-late maturity; very high (1.090-1.095) specific gravity; chips well; average to above average yields; high incidence of vascular discoloration. Kennebec: Medium-late maturity; medium-low specific gravity; significantly above average yields in second and third D of H, significant bulking between first and second D of H; high incidence of vascular dis­ coloration, some internal necrosis; large tubers tend to be rough. Michibonne: Michigan; medium-late maturity; medium-low specific gravity; significantly above average yields; low incidence of vascular discoloration; good smooth type, best suited for fresh pack. Michimac: Michigan; medium-late maturity; medium-low specific gravity; average to above average yields; high incidence of vascular discoloration, some internal necrosis, some scab observed. Oceania (B6090-2): USDA, Beltsville (1980); early-medium maturity, low specific gravity; acceptable chips; significantly above average yields first D of H, not much further bulking; free of internal defects; tuber type very acceptable. Onaway: Early maturity; low specific gravity; does not chip; significantly above average yields first D of H, some bulking after contributes to above average yields; low incidence of vascular discoloration. Oneida: Wisconsin (1977); medium maturity; medium specific gravity; accept­ able chips; above average to average yields first and second D of H; low incidence of vascular discoloration. Russet Burbank; Late maturity; high specific gravity; above average yields second and third D of H; low incidence of vascular discoloration, some internal necrosis, and hollow heart. Superior: Early maturity; medium specific gravity; above average yield first D of H, although it continued to bulk it did not keep pace with later cultivars; low incidence of vascular discoloration. Tobique: New Brunswick, Canada (1977); white skin with red splashes; medium maturity; medium specific gravity; above average to average yields; high incidence of vascular discoloration. B7583-6: USDA, Beltsville; blocky russet type; medium-late maturity; medium specific gravity; slightly below average yields; low incidence of vascular discoloration, hollow heart. MS 2-152: Michigan; medium maturity; medium to high specific gravity; accept­ able chips; above average yields second and third D of H; medium incidence of vascular discoloration. Will be DISCONTINUED. MS 4-169: Michigan; medium maturity; medium to high specific gravity; accept- able chips; average yields, significant bulking between first and second D of H; medium incidence of vascular discoloration. Will be DISCONTINUED. MS 4-377: Michigan; yellow flesh; medium-late maturity; high specific gravity; acceptable chips; above average yields; low incidence of vascular discoloration, some scab observed. MS 4-408: Michigan; yellow flesh; medium-late maturity; medium to high specific gravity; chips well; above average yields; low incidence of vascular discoloration. Will be DISCONTINUED. MS 4-439: Michigan; medium-late maturity; high specific gravity; chips well; slightly above average yield first D of H, no further bulking leads to significantly below average yields later dates of harvest; medium incidence of vascular discoloration. MS 108-5: Michigan; medium-late maturity; medium specific gravity; acceptable chips; above average to average yields; medium incidence of vascular discoloration. MS 305-19: Michigan; yellow flesh; late maturity; high specific gravity; chips well; slightly above average to average yields; low incidence of vascular discoloration, some hollow heart. Will be DISCONTINUED. MS 402-1: Michigan; medium maturity; low specific gravity; chips well, average to significantly below average yields; no internal defects. MS 403-2: Michigan; early maturity; medium specific gravity; acceptable chips; average to significantly below average yields; (no internal data). COMMENTS: Yields did not significantly increase between the second and third dates of harvest and, for the most part, actually decreased. This generalized decrease was only statistically significant (P=.O5) for two entries, Oneida and MS 108-5, however. The fact that yields did not significantly increase can be attributed to the absence of further bulking after August 30 or to differences between the blocks. The decrease in percent B's for all entries over the three dates of harvest indicates that bulking continued past the second date of harvest. There very possibly could have been differences between the blocks such as soil, stand, and tuber initiation which could have contributed to the results obtained. Plant emergence was very slow due to wet soil conditions after planting. It becomes necessary, therefore, to primarily consider differences within each of the dates of harvest rather than differences between the dates of harvest especially for the latter two harvest dates. Many selections had higher incidences of and more severe vascular and/or internal disorders than in past years. This may be a result of this year’s environmental growing conditions. Onaway was the only cultivar not to produce at least marginal chips from the second date of harvest. Chips were made three days after harvest for the first two dates and two weeks after harvest for the third date. All chip samples were kept at room temperature until chipping. B. 10 HILL OBSERVATIONAL TRIAL (Montcalm Experimental Farm) Thirty-six advanced selections and new releases planted on May 7 in unreplicated 10 foot observation plots. All plots received the standard cultural practices mentioned in the Dates of Harvest Trial and were harvested August 27. Data was collected on total yield, maturity, appearance, specific gravity, chip score after harvest, and internal defects (per 20 cut tubers), for each of the entries, Table 2. Several selections deserve notation and/or further testing. Dakchip: (ND88888-2): North Dakota, (19 79); early maturity; chips well; had above average yields but had severe sprouting and vascular discolor­ ation. Tuber shape and smoothness were not uniform. NDD8891-3: North Dakota; medium maturity; acceptable chips; had above average yields but had a medium incidence of vascular discoloration and some internal necrosis. Rideau: Canada; medium maturity; attractive red color; medium specific gravity; had a medium incidence of vascular problems. May have a place in red market (high specific gravity for a red). Yukon: Medium maturity; yellow flesh; attractive type; medium to high specific gravity; chips well; low incidence of vascular discoloration. B6987-184: USDA, Beltsville; late maturity; very high specific gravity; chips well; above average yields; very attractive but did have considerable vascular discoloration and sprouting. COMMENT: As in the dates of harvest study, it was noted that vascular disorders were common. Further tests will be necessary to determine its relationship to the growing season. The Campbell selections were obtained from the breeding program of the Campbell Soup Co. and of these Campbell 13 performed the best, however internal disorders were more prevalent. Them are several promising selections from the Beltsville breeding program which are worthy of further testing. The environment under which these selections have been made and tested may be more like that of Michigan which improves their chances of adaptability to Michigan conditions. There are several selections within the 400 series of the Michigan program which are very smooth, well shaped and attractive. Those with the higher levels of specific gravity will be more vigorously tested in the future. Table 1: YIELDS, SPECIFIC GRAVITIES AND CHIP RATINGS OF SEVERAL CULTIVARS AT THREE DATES OF HARVEST (M.E.F.) August August 9, 1979 August August August 30, August September 24, September 24, 9, 1979 US No.1's cwt/A Specific Gravity 9, 1979 Chip Score 1/ 30, 1979 US No.1's cwt/A 1979Specifi c Gravity 30, 1979 ChipScore September 24, 1979 US No.1'scwt/A 1979Specifi c Gravity 1979 Chip Score September 24, 1979 8/27 2/ Cultivar Atlantic Belchip Belrus Buckskin Butte Croatan Denali Kennebec Michibonne Michimac Oceania Onaway Oneida Russet Burbank Superior Tobique B7583-6 MS 2-152 MS 4-169 MS 4-377 (Y) MS 4-408 (Y) MS 4-439 MS 108-5 MS 305-19 (Y) MS 402-1 MS 403-2 232 269 220 186 77 304 281 247 300 237 350 329 263 224 266 266 229 151 171 255 251 258 277 206 247 244 1.080 1.071 1.073 1.070 1.072 1.062 1.084 1.068 1.069 1.064 1.069 1.059 1.072 1.070 1.071 1.067 1.075 1.075 1.074 1.074 1.074 1.080 1.074 1.074 1.064 1.073 1 1 2 2 4 3 1 3 3 4 2 5 2 3 4 4 3 3 3 2 2 2 2 3 2 2 312 344 235 390 375 343 358 513 516 398 384 407 352 390 343 327 350 390 358 383 407 298 370 384 243 324 empty table cell365 empty table cell 68 1.086 1.074 1.074 1.078 1.082 1.064 1.090 1.072 1.071 1.071 1.062 1.066 1.075 1.081 1.068 1.073 1.079 1.087 1.081 1.084 1.080 1.088 1.079 1.086 1.064 1.073 1 1 1 1 2 2 1 3 1 2 2 4 2 2 2 2 2 1 1 1 1 1 1 1 1 2 309 363 212 390 361 397 390 509 478 412 335 386 278 413 315 352 346 337 378 406 420 275 317 360 283 271 empty table cell357 empty table cell 70 1.084 1.079 1.071 1.079 1.085 1.064 1.094 1.070 1.069 1.071 1.062 1.066 1.073 1.080 1.066 1.072 1.077 1.082 1.083 1.084 1.082 1.081 1.078 1.085 1.063 1.070 2 2 2 3 4 2 3 3 3 3 2 5 2 3 3 2 4 2 2 3 2 1 3 1 3 2 2 3 1 3 4 2 3 3 3 3 2 1 2 3 1 2 3 2 2 3 3 3 3 4 2 1 Average LSD .05 1/ Chip Scores based on PC/SFA chart: l=light; 5=dark. 2/ Maturity: l=mature, vines dead; 3=vines spread green; 1.074 .004 1.076 .004 242 61 1.076 .005 empty table cell empty table cell empty table cell empty table cell 5=vines up, vigorous, flowering. TABLE 2: 10 HILL OBSERVATION PLOT SUMMARY, M.E.F. (1979) E C N A R A E P P A / 2 — — A- A+ A A — A A A + A- A A- - A — A A- A A- + C I F I C E P S Y T I V A R G 1.070 1.068 1.072 1.080 1.070 1.073 1.066 1.062 1.073 1.077 1.080 1.100 1.098 1.063 1.069 1.068 1.070 1.086 1.066 1.065 1.070 1.079 3 — ) A / . T W C ( D L E I / Y 1 6 2 / 8 Y T I R U T A M SELECTIONS BK-73 Campbell 11 Campbell 12 Campbell 13 Dakchip ND8891-3 Neb 1.72-1 Neb A 102.72-2 Neb A 129.69-1 Rideau Yukon USDA -Idaho A68678-1 USDA-Beltsville B6987-184 5/ USDA-Beltsville B6987-184 5/ B7516-7 USDA-Beltsville B7516-9 USDA-Beltsville B7802-2 USDA-Beltsville B7805-1 USDA-Beltsville B7859-3 USDA-Beltsville B8528-3 USDA-Beltsville B8822-9 USDA-Beltsville USDA-Beltsville B8972-1 . 4/ MSU (white) 4-439 MSU (white) 4/ 401-2 4/ 402-4 MSU (white) 4/ 402-6 MSU (white) 4/ 407 MSU (white) MSU (off-white) 4/ 4-198 4/ 402-1 MSU (off-white) 438 177 277 315 369 377 330 292 423 369 284 269 354 469 246 407 284 354 300 192 277 223 307 169 200 200 215 284 269 2 3 3 3 1 2 2 1 3 2 2 1 3 3 1 1 1 1 3 2 1 1 1 2 1 1 1 1 2 _— 1.087 — 1.071 A- 1.073 A 1.069 + 1.061 1 1 1 1 1 — — — — A- A 1.071 1.058 1 1 _— — — 5 — U H % T R ) A E T S T C E F E D L A N R E T N C 0 W O L 2 ( ) L % O I ( H S T C E F E D NECROSIS L A N R E T N L A N R E T N ) T U C I ) T U C 0 2 ( ) INTERNAL 0 2 ( ) ( S T C E F E D % ( E R O C S P I H C / 3 I 40 5 25 40 75 25 25 — 25 15 - 20 5 — 5 — 10 — — 5 — 5 5 1 4 — 2 1 2 1 3 — 4 4 1 — — — — — — — — — 5 — — 10 1 1 1 2 — 2 — 3 1 2 4 1 — — — — — — 5 — — 5 5 25 — — 50 — 5 — — — 10 VASCULAR ( E RE F % UT) C 0 2 ( %) CTS DEF AL N R E NT E I L A N R E T N I 55 90 75 65 25 65 75 100 95 75 80 40 60 65 55 70 95 60 80 100 20 80 85 100 95 100 90 85 95 COMMENTS empty table cell empty table cell empty table cell empty table cell sprouted (severe), vascular (severe) empty table cell 10% knobs empty table cell empty table cell red yellow flesh russet sprouted (slight) sprouted (slight) 10% sungreen, empty table cell empty table cell 15% growth cracks empty table cell dark russet, sprouted russet, pointed russet, 15% sungreen empty table cell empty table cell empty table cell small, sprouted (slight) empty table cell empty table cell empty table cell 50 40 35 30 25 — 25 20 — 35 20 10 — 5 — 5 15 TABLE 2: Con't. ) T U C 0 2 ( ) % ) A / . T W C ( D L E I Y Y T I R U T A M 1 6 2 / 8 E C N A R A E P P A 2 C I F I C E P S Y T I V A R G E R O C S P I H C 3 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ S OSI R C NE ( S T C E F E D L A N W R O E L L T O N H I T R A E H L A N R E T N I ( 0 L 2 ( ) A % N S R T C E E T F E N D I ) T U C R A L U C S A V INTERNAL ) % ( S T C E F E D — ) T U C 0 2 ( % FREE INTERNAL DEFECTS (%) (20 CUT) L A N R E T N I COMMENTS empty table cell SELECTIONS 4 MSU (yellow) 2-171 2-302 MSU (yellow)4 MSU (yellow)4 3-69 4-377 MSU (yellow)4 MSU (yellow)4 4-408 MSU (yellow)4 305-15 MSU (yellow)4 402-5 315 323 246 300 400 423 238 1 3 3 1 2 3 1 A A- A A A- A- A 1.069 1.081 1.079 1.081 1.087 1.082 1.073 empty table cell empty table cell 1 2 — 1 1 1 4 2 — _— 100 80 90 75 65 — — — — 20 10 25 35 empty table cell empty table cell sprouted sprouted (slight) — — — NO DATANO DATA NO DATANO DATAempty table cell - empty table cell empty table cell empty table cell empty table cell empty table cell 95 — 5 empty table cell empty table cell MEAN, S-x 1/ Maturity notes taken on 8/26 303, 13 1 - plants dead - early - Norland maturity 2 - - Norchip maturity 3 - plants spread but still green - Russet Burbank maturity 2/— Appearance - tuber type - rough, deep eyed A average + smooth, attractive 3/—Chip Score based on Potato Chip/Snack Food Association Chart 1 light > 65 (Agtron) acceptable 3 5 dark 25-34 (Agtron) unacceptable 45-54 (Agtron) marginal 4/— MSU flesh color: white, off-white, yellow5/ B6987-184 had 2 seed sources 70 EVALUATE SEVERAL SELECTIONS FOR THEIR YIELD AND PROCESSING POTENTIAL UNDER MICHIGAN CONDITIONS* R.W. Chase, R.B. Kitchen, R.K. Peterson Dept. of Crop and Soil Sciences, Michigan State University MATERIALS AND METHODS; Thirteen cultivars and advanced selections were tested for their yield potential, size distribution and their processability. Two randomized complete block designs, one containing 6 early and one containing 7 late selections, were planted on May 7. Each entry in both designs consisted of 23 foot plots that were replicated 4 times. All plots received standard cultural procedures which included: 200 lbs/A 0-0-60 plow down, 3 lbs/A Eptam preplant incorporate; 600 lbs/A 20-10-10 and 20 lbs/A 15G Temik at planting; 0.5 lbs/A Sencor delayed preemerge; 300 lbs/A 46% urea sidedress; supplimental irrigation and applications of Bravo 500, Monitor and Thiodan as needed. Specific gravity, yield and size distribution, internal defects, and fry color data were taken after harvest and data summarys appear below. EARLY HARVEST Tables 1 and 2 summarize the data from the early harvest design which was harvested on August 27. Specific gravity, total yield, yield over 10 oz., yield 4-10 oz. and yield under 4 oz. were all significant at the (P=.O5) level. Specific gravities ranged from 1.064 to 1.074 with A68599-1 having the highest specific gravity of the early entries. Total yield varied from a low of 266 cwt/A for ALR22-2 to a high of 456 cwt/A for A68710-5. Size over 10 oz. ranged from 33 cwt/A to 211 cwt/A or from 12-47% of the total yields. A68710-5 and Pioneer had the highest cwt/A in this class. The ranges of variation in the 4-10 oz. and under 4 oz. classes were more restricted. It is interesting to note that the percent of total yield in the 6-10 oz., 4-6 oz. and under 4 oz. classes was lowest for A68710-5 but this selection gave a high (12.5) percent of number 2’s. Center slab and internal data are presented in Table 2. Virtually all of the early entries gave acceptable to good fry scores. The one exception was A66107-12 which had a higher incidence of center slabs in the 2-3 category. A72687-11 had a medium incidence of vascular discoloration. Of the six early entries tested, Pioneer and A68710-5 have good yields, acceptable to good fry color, and above average specific gravities. The high incidence of sugar ends and 12% number 2's in A68710-5 makes Pioneer the more attractive selection in our trials. * Projected supported by Ore-Ida Foods, Inc. TABLE 1: ORE-IDA EARLY HARVEST 8/27/79 (M.E.F.) M A T U R I T Y (8/27)1 1.5 1 3 2.5 1 (cwt/a) S P G R A V E I T Y C I F I C ( c o d e d ) 2 68.0 73.5 72.3 69.8 63.8 P L A N T S P L O T / A V E R A G E N O . 23 23 23 22 20 23 empty table cell empty table cell empty table cell empty table cell 1 , 71.5 69.8 empty table cell 4.1 empty table cell 4.3 Y T O T A L I E L D O o z V . Y I E L D ( E c R w t / 1 a ) 0 Y I E L D 4 - - 1 0 o z . ( c w t / a ) 358 354 456 333 266 398 79 54 211 94 33 185 360.6 122.2 9.0 48.7 17.4 32.0 202 216 155 193 162 178 171.9 17.7 45.8 Y I E L D 4 o z . (cwt/a) 74 79 33 31 61 31 51.4 19.5 15.1 < O o 6 4 z V . E - 1 0 o ( R z % 1 ) 0 . ( % ) - 6 o z ( % < N C 4 U o O . 2 z L . ' s L ( % S ( % ) ) ) 22.0 30.8 25.7 20.5 15.3 33.0 28.1 22.3 46.3 22.1 11.7 28.5 38.1 20.0 7.2 9.4 12.3 29.6 31.4 22.9 0.9 1.3 12.5 4.2 3.8 46.5 28.4 empty table cell 7.7 16.3 empty table cell empty table cell 1.2 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 Maturity: 1= mature, vines dead; 3= vines spread, green; 5= vines up, vigorous, flower 2 S.G. coded = (S.G. - 1.000) 1000 CULTIVAR A66107-12 A68599-1 A68710-5 A72687-11 ALR22-2 Pioneer Average CV (%) LSD .05 CULTIVAR A66107-12 A68599-1 A68710-5 A72687-11 ALR22-2 PIONEER TABLE 2: CENTER SLAB FRY DATA3 - ORE-IDA (EARLY) 1 0 L B S T U B E S . / T O T A L N O . C F C F C O O R R L L O H F O L L O W R H E A R T L O R O O R Y Y Y R ( 2 - 3 ( 4 + V A S C U L A R D I S C O L O R A T I O N ) ) N E E C R I N T E R N A L N S U G A J E L L Y E N D / D R S O S I S (0-1)4 15 19 18 20 18 17 21 19 19 20 21 18 empty table cellempty table cellempty table cellempty table cell 6 empty table cellempty table cellempty table cell empty table cell empty table cellempty table cellempty table cell 4 1 1 empty table cell empty table cellempty table cellempty table cell13 empty table cell empty table cell empty table cell empty table cell empty table cellempty table cellempty table cellempty table cell empty table cell empty table cellempty table cellempty table cellempty table cell empty table cell 3 1 3 4 3/8" center slabs from a 10 lb. tuber sample were fried at 365oF for 3 minutes Fry color is based on the USDA Color Standards for Frozen French Fried Potatoes Chart: 0-1 = light; 4+ = dark LATE HARVEST Tables 3 and 4 summarize the data from the late harvest design which was harvested on September 26th. Specific gravity, total yield, yield over 10 oz., yield of 4-10 oz., and yield under 4 oz. were all significant at the (P=.05) level. Specific gravities ranged from 1.074 to 1.091 with A72685—2 having the highest specific gravity. Total yields ranged from a low of 347 cwt/A to a high of 467 cwt/A with A67142-1, A70758-3 and A72685-2 having yields of 450 cwt/A or higher, well above the average and that for Russet Burbank. Yields over 10 oz. were 130 cwt/A or higher for A67142-1, A70758-3, and A72685-2 which represents 28-32% of the total yields for these three selections. Ranges in yields for the 4-10 oz. and under 4 oz. categories w were more restricted. A69327-5 and Russet Burbank gave the highest percent of total yields in the under 4 oz. and number 2’s categories respectively. Table 4 summarizes the center slab fry data and internal defects for the late harvest design. Only A67142-1, A68678—1 and Russet Burbank gave good fry color results. A68678—1 had a medium to high incidence of internal problems with vascular discoloration and sugar ends. Russet Burbank also had a medium incidence of sugar ends. Of the seven late entries tested, A67142-1 appears to be the most promising with its above average yields, good specific gravity, good fry color and freedom from internal defects. A72685-2 had an above average yield and high specific gravity but did not have as good fry color. A70758-3 had an above average yield but below average specific gravity and only fair to poor fry coloration. TABLE 3: ORE-IDA LATE HARVEST 9/26/79 (M.E.F.) ( < 4 Y I E L D O Z . ( c w 1 0 O V E R o z . ( % ) O Z % . 4 - 6 6 - 1 < 4 % 0 O Z O Z . . N O . C U L L S ( % 2 ’ s ) ( % ) A V E R A G E N O P L A N T S P L O T / . 23 22 23 23 23 22 M A T U R I T Y ( 8 / 2 7 ) 1 4 4 3.5 4.5 4 4 S P E C I F I C G R A V I T Y 2 ( c o d e d ) 84.3 79.3 84.0 74.3 79.0 91.0 23 3.5 empty table cell empty table cell 77.0 empty table cell empty table cell 81.3 empty table cell 4.1 empty table cell 5.0 T O T A L Y I E L D ( c w t / A ) 450 347 361 467 348 454 389 402.3 9.9 58.9 O V E R Y I E L D 1 0 O Z . ( c w t / A ) 143 68 33 130 63 143 57 4 —1 0 Y I E L D O Z . ( c w t / A ) 233 234 227 243 225 246 233 t / A ) 33 45 88 61 41 52 44 90.9 35.6 48.0 232.5 12.2 42.1 51.9 23.3 18.0 CULTIVAR A67142-1 A68678-1 A69327-5 A70758-3 A72545-7 A72685-2 Russet Burbank Average CV (%) LSD .05 ) 31.8 32.4 19.3 19.4 37.7 26.7 9.2 28.8 33.8 27.9 30.6 21.5 18.0 37.2 27.4 31.4 32.2 21.9 (%) 7.3 13.1 24.2 13.0 11.7 11.5 3.1 6.1 3.1 empty table cell 3.9 empty table cell 7.0 empty table cell 5.7 empty table cell 3.1 empty table cell 14.4 empty table cell empty table cell empty table cell 14.6 empty table cell 34.0 25.7 empty table cell 11.3 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 Maturity: 1 = mature, vines dead; 3 = vines spread, green; 5 = vines up, vigorous, flower 2 S.G. coded = (S.G. - 1.000) 1000 TABLE 4: CENTER SLAB FRY DATA3 - ORE-IDA (LATE) 1 0 L B S . T O T A L T U B E R S / N O . F R Y C O L O R H E A R T H O L L O W F R Y C O L O R ( 2 - 3 ) F R Y C O L O R ( 4 + ) D I S C O L O R V A S C U L A R A T I O N N E C R O S I S I N T E R N A L J S E U L G L A Y R E E N N D D S / empty table cellempty table cell empty table cell empty table cellempty table cell CULTIVAR A67142-1 A68678-1 A69327-5 A70758-3 A72545-7 A72685-2 Russet Burbank (0-1)4 18 18 11 1 2 10 19 18 18 15 19 18 15 19 empty table cellempty table cell 4 12 empty table cell 6 16 empty table cell empty table cell 1 empty table cellempty table cell 5 empty table cell empty table cell3 empty table cell empty table cell empty table cell2 empty table cell empty table cell 5 empty table cell empty table cellempty table cell empty table cell empty table cell empty table cell empty table cellempty table cell empty table cellempty table cell4 empty table cell empty table cell empty table cell 3 3/8" center slabs from a 10 lb. tuber sample were fried at 365°F for 3 minutes 4 Fry color is based on the USDA Color Standards for Frozen French Fried Potatoes Chart: 0-1 = light; 4+ = dark THE EVALUATION OF PIX, A PLANT GROWTH REGULATOR, FOR ITS EFFECT ON POTATO PLANT GROWTH, TUBER NUMBER, ANO TUBER QUALITY R.K. Peterson, R.W. Chase, R.B. Kitchen Department of Crop and Soil Sciences MATERIALS AND METHODS: Two cultivars, Superior and Russet Burbank, were planted in two separate randomized complete block designs on May 7, each design consisted of 28 ten foot plots of 7 treatments replicated 4 times. The seven treatments included 1 check and 3 rates of PIX (0.044, 0.1 and 0.5 a.i./A) by 2 dates of application (prebloom and 2 weeks after prebloom). All PIX treatments were applied using a standard 3 gallon Hudson sprayer. PIX is a plant growth regulator obtained from BASF Wandotte Corp. All plots received standard cultural practices during the growing season. These included: 200 lbs/A 0-0-60 plowdown, 3 lbs/A Eptam preplant incorporate; 600 lbs/A 20-10-10 and 20 lbs/A 15G Temik at time of planting; 0.5 lbs/A Sencor delayed preemerge; 300 lbs/A 46% urea sidedress; supplemental irrigation and applications of Bravo 500, Monitor, and Thiodan as needed. Height measurements were taken on both cultivars on July 26. Tuber yield (weight, number and size) and specific gravity measurements were taken at the time of harvest and are summarized under each cultivar below. SUPERIOR EXPERIMENT: Plots of Superior received the prebloom spray applications on June 18. At the time of application Superior plots were in 10% flower, stolons were 6-10 inches long and tubers were 1/2 to 1" in diameter. The 2 week after prebloom spray was applied on July 5 (17 days after the prebloom spray). Plots were in full flower with 3-6 tubers per plant and tubers were 1 1/2 - 2" in diameter. All the Superior plots were harvested on August 23. Table 1 summaizes the results of the Superior experiment of all the categories studied, only the total number of tubers and the number of tubers between 2 and 3 1/4" were significant. In both cases significance was at the P - .10 level and no trends were noted. From these results it appears that the timing of and the rates of PIX applied did not appreciably affect the height, yield, size distribution or quality of tubers in the Superior experiment. RUSSET BURBANK EXPERIMENT: Plots of Russet Burbank received the prebloom spray applications on June 22. At that time the plots were in 90% bud, stolons were 4-6 inches long and tubers were 1/2 inch in diameter. The 2 week after prebloom spray was applied on July 5 (13 days after the problem spray). Plots were in full flower, with 5-7 tubers per plant and tubers were 1/2 to 1" in diameter. All Russet Burbank plots were harvested September 26. Table 2 summarizes the results of the Russet Burbank experiment. Significance at the P = .10 level was obtained for yield of number 2's, total tuber number, and number of number 2's. Them appears to be an increase in total tuber number with an increase on the rate of PIX applied. This can be attributed to the increase in the number of tubers under 4 ounces although this category gave no significant differences. From these results it appears that the application of PIX has a variable effect on tuber yield and tuber size. PIX tends to increase tuber numbers in the smaller size categories and as a result increases tuber yields in these categories as well. PIX has the opposite effect on larger size categories. Few of these trends were significant at the P = .10 level, however, PIX has a tendency to increase both the number and weight of tubers in the number 2 category which may be an undesirable feature. empty table cell TABLE 1: PLOT MEANS FOR HEIGHT, SPECIFIC GRAVITY, YIELD AND TUBER NUMBER IN THE SUPERIOR EXPERIMENT G R A V I T Y S P E C I F I C H E I G H T ( 7 / 2 6 ) ( i n c h e s ) 18.8 20.5 20.3 17.5 20.0 20.5 20.3 19.7 19.5 1.067 1.066 1.067 1.066 1.067 1.068 1.066 1.0664 4.3 Y I E L D T O T A L ( c w t / A ) 458 455 455 420 461 452 453 450 U N D E R Y I E L D 2 ” ( c w Y I E L D 2 - 3 1/4" (cwt/A) t / A ) 9 12 14 14 9 12 6 11 306 306 352 281 350 336 321 321 Y I E L D O V E R 3 1 / ( 4 c w " t / A ) 142 138 88 125 103 105 127 118 T O T A L T U B E R S # 67 63 70 64 67 72 64 67 CHECK .044 PRE .1 PRE .5 PRE .044 POST .1 POST .5 POST Average CV (%) LSD .1 # < 2 " T U B E R S 2 - 3 1/4" # T U B E R S X W E I G H T / T U B E R # L b s . X .44 .47 .42 .43 .45 .41 .46 .44 > 3 1/4 " # T U B E R S 11 10 7 10 8 8 10 9 38.6 7 8 8 9 7 9 5 7 49 45 55 45 53 55 49 50 46.4 empty table cell 10.5 6.4 empty table cellempty table cell 8.7 59.0 empty table cell empty table cell 11.7 37.3 empty table cell 6.6 empty table cell5.4 empty table cell empty table cell empty table cell TABLE 2: PLOT MEANS FOR HEIGHT, SPECIFIC GRAVITY, YIELD AND TUBER NUMBER IN THE RUSSET BURBANK EXPERIMENT empty table cell 4 O Z . Y I E L D U N D E 4 - 1 0 Y I E L D O Z . ( c w t / A R # 2 ’ s Y I E L D Y I E L D O V E R 1 0 O Z . ( c w t / A T U B E R S T O T A L N O. . N O U N D E R 4 T U B E R S O Z . . N O 4 - 1 0 N O T V U E R B O E 1 R 0 S O Z . . T U B E R S O Z . N O . # 2 ’ s T U B E R S X X T T O O T T A A L L W # T . / G R A V I T Y S P E C I F I C 1.078 1.075 1.078 1.081 1.078 1.077 1.078 1.0778 T O T A L Y I E L D ( c w t / A ) 433 404 463 474 438 440 426 440 (cwt/A) ) 60 165 84 183 88 243 158 79 78 80 89 80 208 178 183 188 ) (cwt/A) 81 52 56 67 83 56 60 65 128 87 76 170 69 127 94 107 H E I G H T ( I N 7 / 27.5 C 2 6 H ) E S 27.3 27.0 27.8 27.3 26.3 26.3 27.0 4.9 CHECK .044 PRE .1 PRE .5 PRE .044 POST .1 POST .5 POST Average CV (%) LSD .1 7 4 4 5 7 5 5 14 8 10 21 8 16 16 .41 .38 .37 .41 .38 .39 .34 22 28 30 26 29 27 33 28 27 28 38 24 33 26 28 29 26.7 24.0 69 69 82 76 76 74 82 75 10.7 9.9 empty table cell 4.6 10.0 empty table cell 31.8 empty table cell 27.4 empty table cell 38.6 empty table cell 43.2 empty table cell 57 5 .38 13 48.2 empty table cell empty table cell7.9 empty table cell 36.5 empty table cell empty table cell CORRELATION OF THE SUCROSE-RATING SYSTEM TO VARIETY, HARVEST & STORAGE Dept. of Food Science & Human Nutrition & Dept. of Crop & Soil Science Dr. Jerry Cash & Dr. Richard Chase Five varieties, Atlantic, Belchip, Denali, Monona & Norchip were grown at three nitrogen levels of 120, 200 & 280 lbs of nitrogen per acre. Norchip was planted at a 12" spacing whereas the others were spaced at 8”. Plantings were made on May 7. The fertilizer applied was 200 lbs/A of 0-0-60 plowdown and 600 lbs/A of 20-10-10 banded at planting. The additional nitrogen for the 200 pound level was applied as a single side-dressing of uread on May 30. The additional nitro­ gen for the 280 pound level was applied in two applications, May 30 & June 12. Weekly harvests were made July 16,23, 30, Aug 6, 13, 20 & 27. At each harvest, 5 consecutive hills were harvested so that yield, size distribution, set, specific gravity, chip quality, carbohydrates and fat absorption could be determined. Results Table 1 summarizes the yield, size distribution and specific gravity when the main plot was harvested on Sept. 13. These plots were top killed approx. 2 weeks prior to harvest. It is apparent there was no yield response with any variety with increasing nitrogen levels. The residual nitrogen at this location must have been adequate. There was an increase with higher nitrogen in the percent over inch in Atlantic, Belchip, Denali, Monona, however the response was not always consistent. Similarity there was a decrease in specific gravity of Belchip, Denali & Monona with the highest levels of ni­ trogen. Table 2 summarzes the weekly observations made for each variety. Gen­ erally yields showed a continued increase without much difference among varieties. There was some difference in the percentage of tubers under 2 inch with Monona showing the smallest amount, whereas Denali had the highest percentage at the early harvest. This is likely related to numbers and time of tuber set. Tubers over 3% inch were recorded for Atlantic and Belchip on July 30 whereas Monona and Norchip were not noted until Aug 6 and Denali at Aug 13. Specific gravity patterns started at a much higher level than anticipated. The fluctuations were significant and may be related to weather patterns, particularly rainfall. Tuber quality will again be monitored in 1980 in an effort to determine the relationship between management inputs, variety, weather and optimum levels of specific gravity. TABLE 1 THE YIELD, SIZE, DISTRIBUTION & SPECIFIC GRAVITY OF FIVE POTATO VARIETIES GROWN AT THREE NITROGEN LEVELS. (MEF, 1979) VARIETY Atlantic Atlantic Atlantic Atlantic Belchip Belchip Belchip Belchip Denali Denali Denali Denali Monona Monona Monona Monona Norchip Norchip Norchip Norchip NITROGEN LEVEL TOTAL (cwt/A) NO1 (cwt/A) PERCENT OVER 3 1/4" PERCENT UNDER 2" 120 200 280 Ave. 120 200 280 Ave. 120 200 280 Ave. 120 200 280 Ave. 120 200 280 Ave. 485 475 494 485 462 474 459 465 521 488 500 503 404 400 400 401 397 391 399 396 474 454 482 470 456 468 454 459 505 478 488 490 396 391 392 393 382 376 388 382 12.8 2.5 17.6 4.6 2.6 16.1 15.5 3.2 1.4 27.9 35.6 6.3 40.2 1.5 34.6 3.1 3.3 15.1 25.3 2.5 16.8 2.7 2.8 19.1 28.3 2.3 2.5 29.9 36.1 2.3 2.4 31.4 11.8 4.0 4.3 8.5 14.7 3.0 3.8 11.7 SPECIFIC GRAVITY 1.087 1.086 1.089 1.087 1.081 1.082 1.079 1.081 1.095 1.093 1.092 1.093 1.067 1.067 1.063 1.066 1.078 1.078 1.078 1.078 TABLE 2 THE PERFORMANCE DATA OF WEEKLY HARVESTS (MEF, 1979) OF FIVE POTATO VARIETIES. empty table cell Atlantic JULY 16 JULY 23 3.6 3.3 JULY 30 AUGUST 6AUGUST 13AUGUST 20AUGUST 27SEPT. 13 6.3 7.3 9.7 empty table cell Total wt (lbs) Atlantic % under 2" % over 3 1/4" Atlantic Specific gravity Atlantic 69 0 1.090 60 0 19 14 1.091 1.077 15 8 1.081 13 25 1.091 Belchip Total wt (lbs) Belchip % under 2" % over 3 1/4" Belchip Belchip Specific gravity 3.8 55 0 1.083 3.9 33 0 5.8 17 18 1.078 1.072 6.8 6 17 1.068 8.5 11 10 1.077 Denali Total wt (lbs) % under 2" Denali Denali % over 3 1/4" Specific gravity Denali 2.9 82 0 1.093 3.7 57 0 5.4 18 0 1.092 1.076 7.0 27 0 1.079 8.3 17 13 1.088 8.7(270 handwritten) 10 8 1.084 10. 5 (327 handwritten) 6 31 1.088 empty table cell empty table cell 1.082 empty table cell 11.2 (348 handwritten) 5 9 1.076 11.9 (370 handwritten) 8 38 1.075 empty table cell empty table cell 1.077 empty table cell 13.5 (420 handwritten) 9.8 (305 handwritten) 11 —— 9 15 1.091 1.091 empty table cell empty table cell 1.090 Monona empty table cell Total wt (lbs) % under 2" Monona % over 3 1/4" Monona Specific gravity Monona 3.1 43 0 1.073 3.3 34 0 6.1 28 0 1.070 1.064 7.0 11 33 1.062 8.0 13 31 1.066 Norchip Total wt (lbs) Norchip % under 2" Norchip % over 3 1/4" Specific gravity Norchip 4.5 58 0 1.080 7.3 55 0 8.7 16 0 1.079 1.070 12.6 14 8 1.075 10.9 18 — 1.078 8.7 (271 handwritten) 6 20 1.065 9.7 (302 handwritten) 8 — 1.064 empty table cell empty table cell 1.063 11.7 (364 handwritten) empty table cell 13.4 (417 handwritten) empty table cell empty table cell 1.077 10 18 1.075 13 16 1.077 The major factor affecting final quality of processed potato products, especially chips, is the sugar content at harvest and the amount of reducing sugars which accumulate during storage. In a storage situation, the carbohydrate, sucrose, can be enzymatically converted to two, 6 carbon reducing sugars (glucose and fructose), which then react with amino acids during frying, to produce dark colored chips. Under these circumstances, it has been shown to be very important for potatoes being stored for chipping to have minimal sucrose levels when harvested and it is this factor which separates good processing potatoes from poor processors. Since carbohydrate content is so imppotant for finished product quality it is felt that monitoring the sugar changes during growth of tubers can be useful in predicting harvest maturity, however, these changes may be influenced by a number of factors, including, variety, growing conditions, soil fertility and stress conditions. The present study was designed to incorporate some of these factors in order to determine their effects on sucrose content during tuber growth. Five potato cultivars (Atlantic, Denali, Norchip, Monona and Belchip) were grown at three nitrogen levels Harvesting of tubers began on July 16 (70 days after planting) and continued at weekly intervals until September 14 (129 days after planting). Sugar changes were determined by a standard sucrose rating (SR) technique at each harvest date. Figure 1 shows the changes in sucrose content of the various cultivars during their growth. Previous work, using the SR analysis for predicting storage stability, indicates that an SR of 2.8 or less is desirable for good processing potatoes. All the varieties tested were below this level by July 30 (84 days after planting) but tubers were still small and specific gravity was very low at this point. The SR values leveled off and did not change significantly after the July 30 harvest. As expected, chip color tended to follow the same trend (Figure 2) with all cultivars producing chips that rated between 1 and 2 on the PC/SFA 5, code color scale (1 lightest - 5 darkest) by July 30. In conclusion, it seems that sucrose analysis gives an indication of physiological or chemical maturity but it can not be used alone because it does not indicate physical maturity. The SR analysis, combined with a new technique for determining concentrations of glucose and fructose, which we recently developed, may give better information concerning maturity. These analyses may also be useful in making decisions concerning cultural management practices in years when potatoes are grown under stress conditions (i.e., disease, temperature, rainfall). PC/SFA CHIP COLOR FERTILIZER CORRELATION STUDY M.L. Vitosh Department of Crop and Soil Sciences The objectives of this study were to look at potato response at the Montcalm Research Farm to phosphorus supplied as diammonium phos­ phate (DAP) and monoammonium phosphate (MAP) and also to added sulfur (S), boron (B) and zinc (Zn) fertilizers. The experiment was a ran­ domized complete block design with four replications. All treatments except the control received 100 lbs P2 O5 banded at planting time. Sulfur was supplied as gypsum, boron as Borate 68 and Zinc as zinc sulfate. All were applied with the banded fertilizer at planting. Rates were 20 lbs S, one lb B and two lb Zn per acre. Soil test values from the treated plots are shown in Table 1. Phos­ phorus values are extremely high and potassium values are considered to be medium. Uniformity among treatments was good as noted by non-sig- nifieant (NS) LSD tests. Yield, size distribution and specific gravity of Russet Burbank tubers as affected by fertilizer treatments are shown in Table 2. The LSD test indicates that there are no significant differences. The con­ trol treatment, however, was the lowest yielding treatment. Potato petioles were sampled on June 26 and analyzed for 11 elements. The elemental composition is shown in Table 3. DAP and MAP significantly increased the P content with no difference due to P source. Sodium (Na) content was higher with DAP and B but little practical significance can be placed on these differences since Na is not an essential element for plants. Boron and zinc were both significantly increased in the petioles due to their addition in the fertilizer. Both elements were present in adequate amounts in the petioles. In summary, it appears that the soil at the Montcalm Research Farm contains adequate amounts of S, B, and Zn. DAP and MAP are both good sources of P and preformed equally well in this study. Although P fer­ tilizer did not result in a significant yield increase at the 95% level of probability, it would appear that the 35 cwt increase with DAP would easily pay for the 100 lbs of P2 O5. Table 1. Soil test values on samples taken from treated plots in June 1979 (Range 6). Fertilizers Treatments 1 Control DAP 2 MAP3 MAP + 20 lb S MAP + 1 lb B MAP + 2 lb Zn Soil Tests pH 6.1 5.9 5.8 5.7 5.8 5.9 Soil Tests P Soil Tests K Ca Soil Tests Mg Soil Tests 482 471 488 494 474 489 334 356 350 378 350 360 914 972 828 914 857 886 156 153 130 145 135 133 LSD (.05) (NS) (NS) (NS) (NS) (NS) 1 All treatments except the control received 100 lbs 2 P2O5. 3 DAP = Diammonium Phosphate (18-46-0) MAP = Monoammonium Phosphate (13-52-0) Table 2. Total yield, size distribution and specific gravity of Russet Burbank potatoes as affected by Phosphorus, Boron, Sulfur and Zinc fertilizer treatments. Fertilizer Treatments1 Total Yieldcwt/A Over 10 oz.cwt/A Off Typecwt/A A Sizecwt/A B Sizecwt/A Control DAP2 MAP3 MAP + 20 lb S MAP + 1 lb B MAP + 2 lb Zn LSD (.05) 338.2 373.6 355.9 359.6 361.3 363.1 NS 27.7 32.7 23.1 30.7 32.7 25.9 NS 33.2 37.1 39.4 41.1 39.4 40.7 NS 261.2 289.0 275.2 276.5 273.3 281.2 NS 16.1 14.8 18.3 11.1 16.0 15.2 NS Specific Gravity g/cc 1.077 1.080 1.078 1.077 1.076 1.079 NS 1 All treatments except control received 100 lbs P2 O5 2 3 DAP = Diammonium Phosphate (18-46-0) MAP = Monoammonium Phosphate (13-52-0) Table 3. Elemental composition of Russet Burbank petiole samples June 26, 1979 as affected by phosphorus, sulfur, boron, zinc and phosphorus source. K Ca % Mg % Na ppm Mn ppm Fe ppm Cu ppm Zn ppm Al ppm B ppm Fertilizer Treatments1 Control DAP2 MAP3 MAP + 20 lb S MAP + 1 lb B MAP + 2 lb Zn P % .22 .37 .35 .34 .33 .37 LSD (.05) (.04) % 10.6 10.7 11.1 10.9 10.4 11.2 (NS) .77 .68 .75 .74 .68 .78 .43 .40 .40 .39 .37 .41 48 92 52 63 90 46 74 86 90 86 77 98 138 136 143 148 133 146 25 26 24 24 28 26 6 6 7 8 6 7 36 39 40 42 37 50 182 158 179 191 167 184 (NS) (NS) (34) (NS) (NS) (2) (NS) (6) (NS) 1 All treatments except the control received 100 lbs P2O5 2 3 DAP = Diammonium Phosphate (18-46-0_ MAP = Monoammonium Phosphate (13-52-0) FOLIAR FERTILIZER STUDY WITH POTATOES Department of Crop and Soil Sciences Dr. Maurice L. Vitosh. Michigan State University Introduction Recent work on foliar fertilization of soybeans at Iowa State University in 1975 has stimulated interest in foliar fertilization of other crops. Potatoes are a high value crop where a small increase in yield could easily off-set the cost of supplemental foliar fertilizers. The purpose of this study was to evaluate two formulations of Alpine fer­ tilizer sprayed at two rates during initial bloom stage on yield and quality of Russet Burbank potatoes. Procedure The experiment was established on a Montcalm-McBride sandy soil near Greenville, Michigan. The experiment was a randomized complete block design with six treatments and four replications. It was laid out under a center­ pivot irrigation system. Potatoes were planted on May 16, 1979 by the owner. Approximately 200 lbs 0-0-60 was broadcast and plowed down prior to planting, 250 lbs 15-24-0 was used at planting and 554 lbs 28-0-0 was sidedressed during the first cultivation June 18th. The foliar fertilizer treatments were estab­ lished on July 5th using a ten foot boom tractor sprayer. TX-4 Tee-Jet hollow cone nozzels were spaced at 20 inches. The pressure was regulated at 40 psi and travel speed was four mph to give a rate of five gallons per acre. The treatments were applied between the hours of five and eight p.m. Wind speed was less than five mph. The 2.5 gallon per acre rate was obtained by diluting the formulation to half strength with water. Observations of any growth or color difference were made periodically throughout the remaining season. Plots were harvested and sized on October 10th and a sample taken for determination of specific gravity. Results The effects of two formulations of Alpine fertilizer and the two rates of application are shown in Table 1. Total yield and size of tubers were not sig- nicantly affected by the foliar fertilizer treatments. Formula A resulted in a lower specific gravity of tubers than Formula B or the first control. The last control however was not significantly different from the Formula A treatments thus it is doubtful that any real significance can be associated with lower specific gravity of the Formula A treatments. A considerable number of tubers were classified as off-type because of their knobby appearance. This condition has been often associated with differences in growth rate due to water management or climatic conditions. Yields in general were not as high as anticipated based on vine growth and general condition throughout the growing season. Excellent vine growth and color were observed throughout the season. Hopefully information from an adjacent fertility study will offer some management tips for improving yields on this location. In summary, foliar fertilization of Russet Burbank potatoes during initial bloom stage at this location had no effect on yield or quality of potatoes. Fertilizer applied prior to the application of foliar fertilizers was adequate for the production observed. Table 1. Total yield, size distribution and specific gravity of Russet Burbank potatoes as affected by foliar fertilizer treatments. Foliar Treatments Total Yieldcwt/A Over 10 oz.cwt/A Off Typecwt/A A Sizecwt/A B Sizecwt/A Control 2.5 GPA Formula A 5 GPA Formula A 2.5 GPA Formula B 5 GPA Formula B Control 2/ LSD (.05) 233 232 234 229 243 247 1/ ns 11.8 6.5 6.3 11.8 13.4 9.8 ns 47.1 55.5 48.8 53.3 53.6 52.6 ns 142.9 141.0 144.1 129.7 144.1 150.6 ns 31.7 28.8 34.8 34.1 31.7 33.6 ns NS = Not significant 1/ 2/ — Least significant difference at the .05 level of significance. Specific Gravity g/cc 1.080 1.077 1.076 1.081 1.080 1.078 .003 1979 SOIL FERTILITY STUDY WITH POTATOES Dr. Maurice L. Vitosh Departament of Crop and Soil Sciences Michigan State University The following study was conducted in Section 9 of Fairplain Township, Montcalm County. The soil type at this location was classified as a Mont­ calm and McBride loamy sand. Soil samples taken prior to spring application of fertilizer showed the following values: Soil pH Phosphorus (P) Potassium (K) Calcium (Ca) Magnesium (Mg) = 6.4 (Good) = 416 lb/A (Very high) = 433 lb/A (Very high) = 998 lb/A (Adequate) = 148 lb/A (Low due to High K) The soil test indicates an imbalance between K and Mg. According to MSU recommendations when the K to Mg ratio is greater than 3 to 1 Mg will be in short supply. Since the Mg level is above the critical level of 75 lbs Mg per acre, one solution is to allow the K level to decrease by avoiding K applications. The other solution is to supply a soluble source of Mg since lime is not needed. The experiment was a split-plot design with P as the whole plot treat­ ment and N rate, N time, K and Mg as the sub-plot treatments. The K and Mg treatments were broadcast just prior to planting and incorporated. One-half of the experiment received 60 lb P2 O5 as a liquid fertilizer. The other half received only nitrogen. Planting time N was equal for all plots. Russet Bur­ bank cut seed pieces were planted on May 16. Early sidedress N was applied on June 15 and late sidedress N on July 5th. Potato petiole samples were taken on June 26, July 10, 24 and August 8 for nitrate analysis. The nitrate content of petioles is shown in Table 1. The first sampling was taken too early to reflect the nitrogen applications. Potassium alplications had a depressing effect while magnesium significantly increased the nitrate content of potato petioles. These differences remained throughout the entire season. Early sidedress N resulted in higher nitrate contents on July 10 but not at the later sampling dates. It appears that nitrogen supply was very low on July 10 for the late sidedress N plots. Rates of N were not reflected in the petioles until the last two sample dates. On July 24, the 100 lb N rate was significantly different from the 200 and 300 lb rate and on August 7 the amount of nitrate in petioles was proportional to the rate of application. Yield, size distribution and specific gravity of tubers are shown in Table 2. Total yield was not significantly affected by any of the treatments, however, there was a noticeable trend supporting the petiole nitrate content differences due to K and Mg. The application of 200 lbs of K2O tended to decrease yield while 44 lbs of Mg tended to increase yields. The low N rate (100 lbs) resulted in significantly greater yield of A grade tubers (greater than two inches dia­ meter minus those over ten ounces and off type) while the higher N rates sig­ nificantly increased the number of off-type or knobby tubers. Specific gravity of tubers was significantly decreased by 200 lbs K2O and increased by 44 lbs Mg. In concluding, too much K and too Little Mg seems to be the primary soil fertility problem discovered at this site. Although total yield was not sig­ nificantly affected there was a tendency toward improved yield with Mg. The K-Mg relationship can not be fully evaluated here because Mg was evaluated only where 200 lb K2O was applied. Magnesium Without K was not one of the treatments. A response to N above 100 lbs per acre was anticipated but not obtained. Some other factor was limiting the response. It is doubtful that Mg limited N response although this factor was not Looked at using all combinations of treatments. Magnesium was only evaluated at the 300 lb rate of N. Further study is needed to see if there is a N by Mg interaction. Although we did not obtain a significant response due to P at this Lo­ cation, there is still a need to evaluate P fertilization on soils testing high in P, particularily in light of the P responses obtained this season at the Montcalm Experimental Farm. Treatment 19 shown in Table 3 did give the highest yield in this experiment. One can only speculate as to what that yield might have been had we used more phosphorus or no potassium. Table 1. Effect of fertilizer treatments and date of sampling on nitrate nitrogen content of potato petioles - Russet Burbank. Fertilizer Treatments lb/A 100 N 200 N 300 N Sample Date 6-26-79 19,332 a 1/ 19,505 a 18,630 a Early sidedress Late sidedress 17,372 a 18,057 a2/ 0 P2O5 60 P2O5 0 K2O 200 K2O 0 Mg 44 Mg 20,123 a 20,250 a 20,209 b 17,278 a 17,353 a 20,958 b Sample Date 7-10-79 Sample Date 7-24-79 Sample Date 8-7-79 21,603 a 22,640 a 21,762 a 21,603 b 14,662 a 22,154 a 22,178 a 26,234 b 21,762 a 21,762 a 26,096 b 16,345 a 20,684 b 19,258 b 18,380 a 17,643 a 18,932 a 19,374 a 22,686 b 19,320 a 18,380 a 20,259 a 8,546 a 16,822 b 18,699 c 13,918 a 14,293 a — — 21,058 b 17,950 a 13,918 a 15,855 b 1/ Means followed by the same letter are not significantly different (P=0.05) according to the least significant difference test. 2/ Late sidedress N was not applied until July 5. Table 2. Effect of fertilizer treatments and time of application on yield, size and specific gravity of Russet Burbank potatoes. Fertilizer Treatments -lb/A- 100 N 200 N 300 N Early Sidedress Late Sidedress 0 P2O5 60 P2O5 0 K2O 200 K2O 0 Mg 44 Mg Total Yieldcwt/A Jumbo Gradecwt/A A Gradecwt/A B Gradecwt/A Off Typecwt/A 296 a 1/ 302 a 291 a 291 a 290 a 293 a 300 a 294 a 283 a 291 a 308 a 44 a 46 a 37 a 43 a 39 a 44 a 42 a 51 a 37 a 43 a 45 a 174 b 140 a 132 a 142 a 141 a 141 a 154 a 136 a 129 a 142 a 163 a 32 a 35 a 35 a 33 a 32 a 33 a 34 a 32 a 35 a 33 a 37 a 47 a 82 b 87 b 74 a 78 a 74 a 70 a 76 a 83 a 74 a 63 a Specific Gravity -2/cc- 1.077 a 1.075 a 1.075 a 1.075 a 1.074 a 1.076 a 1.076 a 1.078 b 1.074 a 1.075 a 1.078 b 1/ Means followed by the same letter are not significantly different (P=0.05) according to the least significant difference test. Table 3. Influence of nitrogen, phosphorus, potassium and magnesium on yield, size and specific gravity of Russet Burbanks. Treatment No 10 3 9 20 13 19 Treatmen tP2O 5 lb/A Treatmen t K2 O lb/A 0 0 0 60 60 60 0 200 200 0 200 200 Treatment N lb/A 300 300 300 300 300 300 Treatment Mg lb/A 0 0 44 0 0 44 Total Yield cwt/A Jumbo Grade cwt/A A Grade B Grade cwt/A Off Type cwt/A Specific Gravity 300 a1/ 285 a 311 a 288 a 280 a 319 a cwt/A 135 ab 118 a 146 b 136 a 139 ab 163 b 33 a 32 a 43 a 31 a 37 a 36 a 44 a 39 a 45 a 58 a 34 a 45 a 88 ab 96 b 77 a 63 a 70 a 76 a 1.078 b 1.074 a 1.077 b 1.078 b 1.074 a 1.077 b 1/ Means followed by the same letter are not significantly different (P=0.05) according to the least significant difference test. WEED CONTROL IN POTATOES William Meggitt and Richard Chase Department of Crop and Soil Science Herbicide treatments for control of barnyard grass and annual broad­ leaved weeds are shown in Table 1. The moot effective control of barnyard grass was obtained from EPTAM or Vernam (same group as EPTAM) applied preplant incorporated. Sencor, Lexone, or Lorox applied as a delayed preemergence treatment (after weeds had emerged but before potatoes emerged) gave complete control of broadleaved weeds. Lasso or Dual applied pre­ emergence (immediately after planting) gave excellent grass control. The grass control was reduced when the Lasso or Dual application was delayed 10 days and some grass has started to emerge. Appling Sencor or Lexone preemergence resulted in somewhat less control of broadleaved weeds. Combining the Lasso or Dual and Sencor or Lexone or Lorox and appling preemergence or delayed preemergence did not result in effective control of both broadleaved weeds and grasses. Postemergence grass control is possible with new herbicides Hoelon and KK80 not yet registered. Research results in summary show that an effective weed control program in potatoes for annual grasses and broadleaved weeds will require two herbicide application times; at the preplant incorporated or pre­ emergence for annual grasses and delayed preemergence for broadleaved weeds. The study on the effect of Basagran on potato varieties is shown in Table 2. Basagran is effective for control of nutsedge and certain broad­ leaved weeds. There was marked differences in varietal responses to Basagran. Russet Burbank was severely injured and yields reduced by rates of 1 lb/A and by split applications of lower rates (rates necessary for weed consol). Certain varieties; Atlantic, Jewel, Michimac showed little injury and no yield reduction. Onaway showed some visible foliage injury and Superior showed yield reductions. At the present time it is not feasible to pursue the registration and use of Basagran on potatoes because of the injury potential to certain important varieties. TABLE 1: PREPLANT INCORPORATED, PREEMERGENCE AND POSTEMERGENCE WEED CONTROL IN POTATOES, MONTCALM COUNTY, MICHIGAN, 1979 Rate (Ibs/A) 4 1/2 4 1/2 + 1/2 4 1/2 + 3/4 3 + 1/2 4 1/2 + 3/4 3 + 1/2 3 + 1/2 1 + 1/2 3 + 3/4 2 + 1/2 2 + 3/4 2 + 1/2 2 + 3/4 3 + 1/2 2 + 1/2 1 1/2 + 1/2 1 + 1/2 1/2 2 + 1/2 1/2 + 1/4 + 1 Weed Control Ratings* BG Weed Control Ratings* PW Weed Control Ratings* LQ Cwt/A A’s Total Specific Gravity 9.3 9.8 10.0 9.7 10.0 9.9 10.0 9.3 10.0 9.0 7.8 9.3 9.8 8.3 8.3 9.2 7.0 6.0 6.0 9.5 9.5 9.0 0.0 7.0 10.0 10.0 10.0 10.0 9.9 10.0 9.0 10.0 10.0 9.8 9.7 10.0 9.0 9.3 10.0 9.3 8.7 9.0 10.0 9.7 10.0 0.0 8.3 10.0 10.0 10.0 10.0 10.0 10.0 9.3 10.0 10.0 9.8 9.7 9.9 9.0 9.0 9.7 9.3 8.7 8.0 10.0 9.8 10.0 0.0 280 351 320 331 360 335 342 299 337 350 324 306 340 311 346 335 306 314 315 350 355 331 114 329 400 383 407 405 407 403 352 417 416 375 382 393 371 406 393 381 386 368 414 403 388 142 1.079 1.082 1.077 1.076 1.075 1.079 1.081 1.080 1.079 1.079 1.079 1.077 1.080 1.077 1.080 1.080 1.078 1.077 1.078 1.079 1.078 1.078 1.077 Trt. No. Treatment Eptam (ppi) Eptam + Sencor/Lexone (ppi) Eptam (ppi) + Dupont 6573 (d. pre) Eptam (ppi) + Sencor/Lexone (d. pre) Eptam (ppi) + Sencor/Lexone (d. pre) Eptam (ppi) + Sencor/Lexone (d. pre) Vernam + Sencor/Lexone (ppi) Prowl + Sencor/Lexone (ppi) Eptam (ppi) + Lorox (d. pre) Lasso (pre) + Sencor/Lexone (d. pre) Lasso (pre) + Lorox (d. pre) Dual (pre) + Sencor/Lexone (d. pre) Dual (pre) + Lorox (d. pre) Antor (pre) + Sencor/Lexone (d. pre) Dual + Sencor/Lexone (pre) MON 097 (pre) = Sencor/Lexone (d. pre) Surflan (pre) + Sencor/Lexone (d. pre) Sencor/Lexone (d. pre) Lasso + Sencor/Lexone (pre) Sencor/Lexone (d. pre) + Sencor/Lexone + Hoelon (post) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16 17. 18. 19. 20. 21. 22. 23. Sencor/Lexone (d. pre) + KK 80 + X-77 (post) Lexone Dry Flow (d. pre) No Treatment 1/2 + 1 + 1 pt. 1/2 - *Rating based on a 1-10 scale; 0 = no injury, 10 = complete kill TABLE 2: POSTEMERGENCE INJURY STUDY IN POTATOES MONTCALM COUNTY, MICHIGAN, 1979 Variety Treatment Rate (lbs/A) R. Burbank R. Burbank R. Burbank R. Burbank R. Burbank R. Burbank 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell Onaway Onaway Onaway Onaway Onaway Onaway Superior Superior Superior Superior Superior Superior Michimac Michimac Michimac Michimac Michimac Michimac Jewel Jewel Jewel Jewel Jewel Jewel Atlantic Atlantic Atlantic Atlantic Atlantic Atlantic 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell 1. Basagran 2. Basagran 3. Basagran (Split) 4. Basagran + Oil Conc. (Split) 5. Basagran + Oil Conc. (Split) 6. No Treatment 1 2 (1)2 (3/4 + 1 qt)2 (1 + 1 qt)2 empty table cell cwt/A cwt/A Total Specific Gravity * Injury Rating 343 327 280 244 288 359 340 322 310 312 296 349 237 203 203 235 242 245 366 382 367 378 363 405 306 295 387 356 327 346 400 343 349 351 333 359 1.079 1.079 1.074 1.075 1.076 1.076 1.067 1.064 1.067 1.067 1.065 1.066 1.068 1.069 1.065 1.070 1.069 1.069 1.069 1.069 1.069 1.070 1.071 1.071 1.085 1.086 1.086 1.087 1.084 1.083 1.089 1.090 1.086 1.088 1.088 1.085 4.3 5.3 4.3 3.7 4.0 0.0 3.3 4.7 3.7 1.7 2.3 0.0 1.7 2.3 1.7 0.3 0.3 0.0 1.0 2.3 0.7 1.0 1.3 0.0 0.7 1.0 0.7 0.3 1.0 0.0 3.3 4.0 3.0 1.7 2.7 0.0 A's 290 259 191 210 224 307 329 309 288 298 265 336 221 187 193 226 234 226 347 365 349 365 348 389 275 269 370 338 300 315 385 329 332 339 309 348 * Rating based on a 1-10 scale; 0 = no injury, 10 = complete kill IMPACT. BIOLOGY AND MONITORING OF INSECT AND NEMATODE PESTS OF POTATOES E. Grafius, G. W. Bird, J. W. Noling, and M.. A. Otto Department of Entomology Current strategies for control of insect and nematode pests of potatoes (primarily the use of chemical insecticides and nematicides) have proven to be very effective under a wide variety of conditions. However, the costs of these controls are high (an average of approximately $75 - 100 per acre, or $3-4 million to the Michigan potato industry = 7-9% of gross sales). The primary goal of these studies is to minimize the costs of insect and nematode control by determining the levels of damage that can be sustained without significant reduc­ tions in yield (economic thresholds). In addition to studying the effects of specific pests on potato yield, it is understood that any environmental factor that reduces plant vigors (e.g. poor soil nutritional levels, poor soil moisture, or the presence of other pests) will act to increase the potato plant’s susceptibility to damage. The economic thresh­ old, then, will vary depending on these factors, as well as factors such as potato cultivar and the stage of plant growth at the time of damage. A secondary objective of these studies is to gather information on life history and biology of the various pests and to determine the best methods for detection and sampling of these pest populations. The studies were divided into two parts: 1) The impacts of Colorado potato beetle (CPB) foliar feeding and Pratylenchus penetrans (root lesion nematode) damage under various conditions, and 2) The impact of foliar feeding by cutworms and the potential for tuber damage. Field Plots CPB/Nematode Studies Seedpieces (cv Superior) were planted on May 17, 1979 at the Montcalm Potato Research farm in Entrican, Michigan. Each plot consisted of four rows 50 ft (15.24 m) in length and 34 in (.86m) apart, with 8 to 12 in. (20.5-30.5m) spacings between plants. Plant growth and development was monitored at various intervals throughout the season. This was accomplished by randomly selecting two plants from the outside rows of each plot and 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 technique) for nematode analysis were taken by core sampling the two outside rows of each plot. Root samples (shaker tech­ nique) 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 commercial irri­ gation practices. Plants were sampled weekly (40 plants/wk) to determine CPB population densities and instar distributions. Plots were treated with two levels of NPK fertilizer (0 and 500 lb/acre, NPK 20-10-10) and a nematicide (1,3-D broadcast 20 gal/acre). Plots treated with 1,3-D were injected to a 8-7 in (15-20 cm) soil depth on April 1, 1979. Those plots to receive fertilizer were also sidedressed during hilling at an application rate of 145 lb/acre (45% urea) on June 22, 1979. Insect control programs were initiated at various times during the season to achieve three levels of plant defoliation (no defoliation, early-season defoliation and full-season defoliation). Within the no defoliation plots, foliar treatments were applied as needed for CPB control. An insect control program was not initiated until flowering within the early- season defoliation plots. No insecticides were applied season long within the full-season defoliation plots. A complete random block, two factorial design was used to analyze the data, with each treatment replicated five times. Within the no defoliation plots, total yield increased with nematicide application and fertilizer (Table 1). Total yield was significantly increased within the no defoliation plots when compared to the unfertilized, fumigated full season defoliation plots (P = .05). Total yields were significantly in­ creased in the no defoliation plots, with the exception of the no defoliationunfert ilized treatments with no nematicide application (P = .05). Highest total yield of Grade A potatoes were observed in the no defoliation plots (Table 1). Yield of Grade A potatoes were significantly increased in the no defoliation plots, with the exception of the no defoliation, unfertilized treatments with no nematicide application (P = .05). Highest total yield of Grade B potatoes occurred in both the early and full season fertilized plots with no nematicide treatment (Table 1). Yield of Jumbo grade potatoes were significantly increased in the fumigated no defoliation plots (Table 1) (P - .05). Regardless of the treatment, yields of Jumbo grade potatoes increased with the application of fertilizer. No significant differences in the soil population densities of P. penetrans were observed among the plots except for the sample of August 8, 1979. Soil population densities of P. penetrans were significantly lower in the early season defoliation, fumigated plots without fertilizer compared to the unfertilized early season defoliation plots with no nematicide treatment (P = .05) (Table 2). There were no significant differences in either the root or total population densities of P.. penetrans season long (P = .05) (Table 3 and Table 4, respectively). . Table 1 Influence of selected management inputs on the yield and grade of potatoes (cv Superior) YIELD (CWT/ACRE) YIELD (CWT/ACRE) TREATMENT Defoliation Level Pre-plant Fumigation (Telone II) Ferti­ lizer 1. No defoliation 2. No defoliation - + - - 3. No defoliation - + 4. No defoliation + 5. Early-season + defoliation - - - 6. Early-season defoliation 7. Early-season defoliation 8. Early-season defoliation 9. Full-season defoliation 10. Full-season defoliation 11. Full-season defoliation 12. Full-season defoliation + + + - - + - + + - - + + YIELD (CWT/ACRE) A B Grade 237.2bc1 257.8c 252.6c 258.4c Grade 7. lab 5.5a 8.9abc 6.8ab Jumbo Grade 6.6ab 33.0c 16.8b 53.1c YIELD (CWT/ACRE) Total 250.9b 296.3c 278.3c 318.3c 183.4a 8.8abc 2.9a 195.lab 193.3ab 6.3ab 5.2ab 204.8ab 194.7ab 10.2bc 2.9a 207.8ab 184.8a 6.8ab 7.2ab 198.8ab 187.0a 6.5ab 4.5ab 197.9ab, 176.0a 8.0abc 2.6a 186.7a 201.9ab 10.9c 4.6ab 217.5ab 197.9ab 7.4abc 8.9ab 214.2ab 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. Table 2 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT Defoliation Level Pre-plant Fumigation (Telone II) 1. No defoliation - + 2. No defoliation 3. No defoliation 4. No defoliation 5. Early-season defoliation 6. Early-season defoliation 7. Early-season defoliation 8. Early-season defoliation 9. Full-season defoliation 10. Full-season defoliation 11. Full-season defoliation 12. Full-season defoliation - - + — + — + — + + - + P. penetrans per 100 cm3 soil P. penetrans per 100 cm3 soil P. penetrans per 100 cm3 soil Ferti­ lizer 6/12/79 8/06/79 9/11/79 — + - — + + — — + + 20.4a1 17.0a 15.4a 19.6a 25.8a 28.8a 20.8a 11.0a 80.6ab 24.0ab 26.8ab 18.8ab 178.4a 157.0a 115.2a 73.4a 80.8b 149.8a 9.2a 97.2a 41.0ab 128.6a 15.2ab 65.8a 28.6a 35.4ab 160.8a 17.6a 18.2a 14.6a 21.4ab 94.6a 24.8ab 240.0a 18.2ab 78.0a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. Table 3 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) Pre-plant Fumigation (Telone II) Ferti­ lizer - TREATMENT Defoliation Level 1. No defoliation 2. No defoliation 3. No defoliation 4. No defoliation 5. Early-season defoliation 6. Early-season defoliation 7. Early-season defoliation 8. Early-sea.son defoliation - - + - + - + - + P. penetrans per gram root tissue P. penetrans per gram root tissue P. penetrans per gram root tissue 6/12/79 8/06/79 9/11/79 104.6a 1 147.0a 82.8a 150.8a 96.4a 50.2a 189.2a 118.4a 411.0a 386.0a 563.6a 288.0a 96.0a 289.6a 573.2a 85.4a 143.4a 490.6a 98.4a 240.6a 325.8a 54.0a 89.6a 73.2a 85.0a 49.6a 102.2a 207.4a 156.6a 407.2a 171.6a 300.6a 195.2a 447.8a 64.8a 284.8a - - + + + + - - + + 9. Full-season defoliation - 10. Full-season defoliation 11. Full-season defoliation - + 12. Full-season defoliation + 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. Table 4 Influence of selected management inputs on population density of P. penetrans on potatoes (cv Superior) TREATMENT P. penetrans per 100 cm3 soil and per gram root tissue combined P. penetrans per 100 cm3 soil and per gram root P. penetrans per 100 cm3 soil and per gram root tissue combined Defoliation Pre-plant Fumigation (Telone II) Ferti­ lizer Level 6/12/79 1. No defoliation - - 125.0a1 2. No defoliation 99.8a - + 8/06/79 tissue combined 9/11/79 223.4a 201.2a 238.6a 168.2a 589.4a 543.0a 678.8a 361.4a 111.8a 69.8a 149.8a 435.6a 723.0a 145.8a 176.2a 194.6a 587.8a 382.6a 454.4a 76.0a 119.2a 273.2a 143.4a 282.8a 568.0a - - + - + - + + - - + + - 3. No defoliation 4. No defoliation + 5. Early-season defoliation 6. Early-season defoliation 7. Early-season defoliation 8. Early-season defoliation 9. Full-season defoliation 10. Full-season defoliation 11. Full-season defoliation 12. Full-season defoliation + - 114.6a 231.2a 395.2a + - + 133.6a 307.6a 687.8a + 76.0a 89.8a 362.8a 1 Column followed by the same letter are not significantly different (P = 0.05) according to the Student-Newman-Keuls Multiple Range Test. Cage Studies Seedpieces (cv Superior) were planted on May 24, 1979 at the Montcalm Potato Research Farm in Entricat, Michigan. Each plot consisted of two rows 6 ft (1.83m) in length and 34 in (.86m) apart, with 8 to 12 in (20.5-30.5cm) spacings between plants. Twenty-seven insect cages, measuring 6 ft by 6 ft (1.83m3), were erected over the plots after planting. Cages selected at random were assigned 1 of 9 different treatments. A treatment consisted of 1 of 3 population levels of CPB and 1 of 3 population levels of P. penetrans. The population levels were achieved by stapling egg masses to the leaves of the newly emerged plants within the cages, allowed them to hatch and then manipulated the plant densities to either 0, 10 or 20 larvae per plant. The nematode population levels of P. penetrans were achieved by various techniques. The low initial population levels were achieved by pre­ plant fumigation with Telone II (20 gal/acre) on May 1, 19 79. The medium population levels represent natural field populations. The high population levels of P. penetrans were achieved by complementing the natural field populations with a liquid suspension of nematode obtained from potato roots cultured in the laboratory. A 10 ML aliquot of the nematode suspension was applied at planting to these treatments and represents an approximate addition of 500 nematodes to the root rhizosphere of the germinating potato plant. Plant growth and development was monitored at various intervals throughout the season. This was accomplished by randomly selecting a plant from one specific row of each plot and then returning them to the laboratory for analysis. In the laboratory, root weight, stem weight, leaf weight, leaf surface area, 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 removing the soil adjacent to plant roots. Root samples (shaker technique) were derived from plants returned to the laboratory for plant growth analysis. At harvest, the remaining row within each plot was harvested, graded and weighed. During the season, plants were maintained under normal commercial irriga­ tion and disease control practices. A completely randomized, 2 factorial design was used to analyze the data, with each treatment replicated three times. Larval feeding, by the CPB, appears to directly influence the population dynamics of P_. penetrans and the growth and development of the potato plant. The direct effect of the CPB feeding was a reduction in leaf weight which increased with increasing beetle density (Fig. 1). As larvae reduced the leaf dry weight there was a corresponding reduction in the plant root dry weight (lowest in the 20 beetle per plant treatments, Fig. 2). These changes are directly reflected in the reduced plant and tuber weights thru time for the beetle infested treatments (Fig. 3 and Fig. 4, respectively). Beetle feeding had no significant influence on soil population densities of P. penetrans season long (Fig. 5). The root population density of P. penetrans tended to be lower in the beetle infested treatments than in the beetle free treatments (Fig. 6). By reducing the leaf weight thru time, beetle feeding influences the size of the total root system and also the of P. penetrans per gram of root tissue is affected. Both nematodes and beetles affect the final tuber yield, with the Colorado potato beetle having the most significant impact in terns of decreasing yields (Fig. 7). Total yield of potatoes decreased with increasing beetle density per plant and with increasing population level of P. penetrans. Fig. 5 Fig. 6 CPB/Russet Burbank Yields Another portion of the field plot was set up as a preliminary study of the impact of CPB foliar feeding on yield of Russet Burbanks and the effects that time of defoliation have on this impact. Plots were four rows by 25-50 ft (depending on treatment) and the middle two rows were harvested for yield data, as before. There was a mean of approximately 7-10 CPB adults and/or larvae per plant from July to mid-August. The most severe damage occurred from June through mid-August (Fig. 8). Damage after mid-August (Temik treatment) caused no further yield reductions, in part due to reduced feeding pressure by CPB adults and larvae. Although Russet Burbank is a late season variety, the defoliation that had occurred by mid-August (nearly 100%) was too severe to allow recovery and the mean yield from plots treated with foliar insecticides late in the season was no different from the mean yield in plots left untreated. As was the case in 1978, the most severe CPB feeding pressure occurred in early August from newly-emerged adults and the few remaining larvae. The 1979 results reinforce those of 1978, indicating that the timing of defoliation is critical in determining its impact on potato yield, particularly as this timing relates to the growth stage of the potato plant. An additional benefit of the CPB studies was the identification of at least two species of predator on CPB larvae, one parasite, and a disease acting on larvae in the study area. These will be monitored more closely in the future with the possibility of using them as aids in control of CPB. Cutworm Complex Studies Our cutworm complex research has been proceeding in 3 areas to provide the necessary information for the formulation and implementation of management strategies. These areas include: 1) sampling or biological monitoring, 2) dynamic economic threshold determination, and 3) cultural practice manipulations to reduce tuber feeding. Monitoring cutworm population levels is important since they are sporadic pests and it is not necessary to control them every year. We focused on variegated cutworms (VCW) when we began our research. However, 3 other species are commonly found as well. Darksided cutworms will cut stems early in the season. They usually arc not a major problem unless large larvae attack newly-emerged plants. Black cutworms (BCW) are frequently found in southeast Michigan potato fields and sporadically in other areas starting in July. This second generation follows the one that damages corn and soy beans. BCW populations now appear to bc more closely associated with the tuber feeding problem than arc VCW populations and more work will by done on this in 1980. Spotted cutworms are also commonly found in potato fields in July and August. They arc foliar feeders similar to VCW’s but do not consume as much foliage and have not been implicated in the tuber feeding problem. Thus, they are not a serious concern at this time. Fig. 7 Figure 8 Cutworm sampling is difficult and time consuming. In order to more efficiently utilize larval sampling resources, a system of monitoring regional adult moth activity is being developed. Coupling this information With developmental information will allow us to concentrate sampling effort at appropriate times. Traditionally, black light traps have been used to monitor flight activity. However, it takes a lot of time and knowledge to sort and count trap catches. This minimizes the number of locations that can be observed. In 1979 VCW sex attractant traps were tested. Many more trap locations were used because of their specificity and ease of monitoring. Another advantage was illustrated at the farm in 1979. June beetles were abundant and destroyed many of the black light trap specimens in June and July. Sex attractant traps did not have that problem and were thus a better indicator of adult activity (Fig. 9). Information on the relative density of the VCW population would also be very useful. It might be possible to use this system within or at least between seasons to give a better picture of the relative density. An illustration of this potential is seen in data from the Hudsonville muck area. 1977 was an "outbreak" year for VCW's, the population crashed in 1978, and the population increased in 1979. These population trends did appear at least between seasons in black light trap information (Figure 10). Work will continue in this area in 1980. Dynamic Economic Threshold Determination for VCW After assessing population levels, it becomes necessary to make a decision on the appropriate management action. Many factors enter into this decision. Rarely will a simple economic threshold (e.g. 15 cutworms per plant or row foot) be entirely satisfactory. In 1979 the influence of several factors (e.g. VCW density, time of infestation, potato variety, time of planting and soil moisture) on yields and the amount of tuber feeding were investigated. VCW density and time of infestation were controlled in microplots planted with the variety Onaway, since most tuber feeding has been reported on early varieties. Aluminum flashing barriers were used to make the 9 x 12 foot micrplots, which held 3 rows 34 inches apart with 7 or 8 plants 8 inches apart in each row. Microplots were artificially infested with either 0, 2, 6, or 18 lab reared second or third instar VCW larvae on 11 July. There were 6 replications of each density. A second release was made 3 weeks later, but only 3 or 4 replications of each density were possible due to natural infestations in several microplots. There was virtually no tuber feeding even with the high VCW density or the late infestation time. The foliar feeding resulted in no statistically significant differences in specific gravity or yield at either the first or second releases (Figures 11 and 12). The reason for this lack of differences is that the 95% confidence intervals increase tremendously as the VCW density increases. Unirrigated microplots showed significantly reduced yields compared to the irrigated ones, but again, there were no significant yield reductions due to different VCW densities and there was no tuber feeding. Apparently the reason for this is that there was higher mortality of the VCW's. There was virtually no tuber feeding in the plots designed to assess the influence of variety, planting time, and depth of hilling on subsequent tuber feeding. Figure 9 Figure 10 Figure 11 Figure 12 Conclusions The results of the above studies indicate that the interactions between potato yield, defoliation, nematode damage, and environmental factors are extremely complexed. The cutworm problem is also difficult, particularly in detection and sampling. However, with increased understanding, we should soon be able to begin predictions of safe levels of infestation, where the cost of control greatly exceeds the benefits of preventing the slight crop losses that might occur. EFFECT OF NEMATICIDES ON THE CONTROL OF PRATYLENCHUS PENETRANS AND POTATO YIELDS G.W. Bird and J. Noting Department of Entomology One liquid and two granular nematicides were evaluated for control of Pratylenchus penetrans associated with Solanum tuberosum (cv Superior) pro­ duction. A complete randomized block design was used with each treatment, replicated 5 times. Seed pieces were planted May 10, 1979 (degree days at base 10 G (DD10) = 196) 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. Both Nemacur 15G and Nemacur 3S were, in addition to the single application treatment, also applied in a split application, receiving the second application at hilling (DD10 =790, June 25, 1979). Monitor was applied when necessary for insect control, and irrigation water as needed throughout the season. Sool samples for nematode (centrifugation-flotation 1.14 specific gravity sucrose) were taken immediately before planting, twice during the season (DD10 = 753, June 25, 1979; DD10 = 1810, August 21, 1979) and at harvest on September 21, 1979 (DD10 = 2285). Root samples were processed for nematodes (shaker technique) at DD10 = 753 and 1810. The center two rows of each plot were harvested, graded and weighed. Temik 15G significantly (P = 0.05) increased total tuber yield and yield of Grade A and oversized tubers. There were no significant differences in soil population densities of P. penetrans among the plots at DD10 = 197 and 753. All treatments significantly reduced P. penetrans soil population densities at DD10 = 1810 and 2285. All treatments significantly reduced the root population densities of P. penetrans at DD10 = 753 and DD10 = 1810. The sum of the root and soil population densities indicated a significant population decrease for all treatments at DD10 = 753 and DD10 = 1810. Table 1. Effect of nematicides on Pratylenchus penetrans and potato yields. Pratylenchus Pratylenchus penetrans per DD101 Pratylenchus penetrans Pratylenchus penetrans per DD101 Treatment, for­ mulation and rate per acre Pratylenchus penetrans per Pratylenchus penetrans per DD101No. per 100 cm3 DD101No. per 100 cm3 soil 196 soil 753 penetrans per DD101 No. per 100 cm3 soil 1810 No. per 100 cm3 soil 2285 per DD101 No. per g root 753 No. per g root 1810 Pratylenchus penetrans per DD101 No. per g root plus No. per 100 cm3 soil 753 Pratylenchus penetrans per DD101No. per g root plus No. per 100 cm3 soil 1810 Tuber Yield (ctw per acre) A Grade Tuber Yield (ctw per acre) B Grade Tuber Yield (ctw per acre) Oversize Grade Tuber Yield (ctw per acre) Total Check 30.0a2 38.0a 138.0b 135.0b 111.0b 530.0b 149.0b 668.0b 148.6a 8.8a 2.8a 160.2a Temik 15G (3 lb a.i./Acre) Nemacur 3S (3 lb a.i./Acre) Nemacur 15G (3 lb a.i./Acre) Nemacur 3S (3 lb + 3 lb a. i./Acre) Nemacur 15G (3 lb + 3 lb a.i./Acre) 21.0a 25.0a 5.0a 8.0a 4.0a 8.0a 39.0b 13.0a 188.5b 7.7a 12.3b 208.5b 29.0a 34.0a 21.0a 50.0a 24.0a 46.0a 58.0a 66.0a 165.4a 6.8a 5.0a 177.2a 21.0a 31.0a 25.0a 47.0a 46.0a 102.0a 77.0a 135.0a 164.7a 9.2a 7.0a 180.9a 18.0a 22.0a 7.0a 14.0a 11.0a 66.0a 33.0a 73.0a 151.9a 10.2a 7.2a 169.3a 22.0a 36.0a 10.0a 30.0a 45.0a 77.0a 81.0a 87.0a 166.1a 9.4a 5.3a 180.8a 1DD10 = degree day accumulation base 10 C. 2Column means followed by the same letter are not significantly different (P = 0.05) according to the Student- Newman Keul Multiple Range Test. EFFECT OF POTATO SEED PIECE TREATMENT ON STAND AND FIELD - 1979 Department of Botany and Plant Pathology H.S. Potter Potato seed piece treatment tests were conducted at the Montcalm Experimental Farm primarily to evaluate chemicals used by Michigan farmers to reduce seed piece decay. Certified Sebago seed was cut and treated before planting on May 12. Chemicals were applied to seed pieces by either dusting in paper bag or by dipping for 2 minutes and allowing them to dry. All seed was planted by hand within a few hours after treatment. Planting was done with the seed pieces 9 inches apart. Treatments were randomized and replicated three times in a single block planting. Plots consisted of a single row 50 feet long and 34 inches wide. Sprays were applied at regular intervals for control of disease and insects and irrigated when necessary to maintain a vigorous growth. Cool weather delayed sprouting but once growth started the stand was good in most cases. A stand count was taken 4 weeks after planting and again 2 weeks later. One of the most effective of the standard seed treatments tested was Captan­ Streptomycin which was superior to captan by itself. A captan-Terraclor combin­ ation also resulted in a better stand and a higher yield than either captan or terraclor or alone. Sodium hypochlorite had one of the best stands of any of the treatments and one of the highest yields. The Kalo experimental compounds KL 4S9, 490 and 491 all had a good stand and high yields. KL 489 was particularly outstanding. The Kocide 101 treatments with and without Firbark were phytotoxic. The 1 lb rate of application was a mistake, it whould have been only 4 oz per acre. The plain water dip reduced the stand and the yield below that of the dry check (no treatment). 1979 RESULTS: POTATO SEED TREATMENT TRIALS METHOD OF APPLICATION % STAND1 YIELD CWT/a 1 TREATMENT TERRACLOR 10D 1LB/CWT OF SEED TERRACLOR 5D 1LB/CWT OF SEED TERRACLOR + TERRAZOL (SUPER x) 10D = 2 1/2D TERRACLOR 75W 1LB/10 GAL WATER CAPTAN 10D 1LB/CWT OF SEED CAPTAN + TBZ 10D + 1/2D 3/4 LB/CWT OF SEED CAPTAN + TERRACLOR 10D +10D 1LB/CWT OF SEED CAPTAN + STREPTOMYCIN 10D + 10D 1LB/CWT OF SEED POLYRAM 10D 1LB/CWT OF SEED DITHANE M-45 10D 1LB/CWT OF SEED KL 489 (KALO) 5W 15 1/4 GR/2 GAL OF WATER KL 490 (KALO) 10W 151/4 GR/2GAL OF WATER KL 491 (KALO) 25W 15 1/4 GR/2GAL OF WATER CHLOR1NE D1OX1DE (PENETRAAT CLO2) 100PPM SODIUM HYPOCHLORITE (CLOROX) 500PPM KOCIDE 10.1 + FIRBARK 10D + 5D) 1LB/CWT OF SEED KOCIDE 101 20D 1LB/CWT OF SEED WATER NO TREATMENT DUST DUST DUST DIP DUST DUST DUST DUST DUST DUST DIP DIP DIP DIP DIP DUST DUST DIP — LSD .05 empty table cell US # 1 285.6 kl 258.6 h i gh g g j k i i 335.5abcdef de 330.0 303.8 312.4 336.4abcdef 354.0ab 328.7 def 311.8 354.9a 344.7abcd 342.6abcde 325.6 def 353.4abc 155.4 120.6 266.6 271.8 22.4 YIELD CWT/a 1 B GRADE 8.3 3.7 6.8 6.8 7. 7 9.2 5.2 5.2 4.9 4.0 6.8 6.2 4.9 4.6 6.8 4.0 4.6 7.7 5.5 N.S. efghi efghi fghijk fghij fghij defgh 81.3 72.2 85.9abcdefg 81.8 79.3 80.8 89.6abcde 93.9ab 80.8 83.3 91.9abc 93.0ab 90.3abcd 87.9abcdef 92.9ab 29.7 36.4 67.2 75.8 8.3 n n lm jk SMALL LETTERS INDICATE TREATMENTS THAT DO NOT DIFFER SIGNIFICANTLY AT THE 5% LEVEL ACCORDING TO THE LSD TEST. APPLICATIONS OF FUNGICIDES FOR DISEASE CONTROL BY SOLID 1979 FIELD TRIALS ON POTATOES TO COMPARE THE SET IRRIGATION, BY BOOM SPRAYER AND BY AIRCRAFT Department of Botany and Plant Pathology H.S. Potter Investigators: H. S. Potter, Department of Botany and Plant Pathology Cooperators: Michigan Stats University, East Lanning, Michigan 48824. Allen Grigg, grower James Crosby, Mootcalm Alen Grigg Farms, Lakeview, MI. Russet Burbank Extension Director Location: Variety: Diseases and Pathogens: Early Blight Alternaria solani Late Blight Phytopnthora Infestans Botrythis Blight Botrytis spp. Soil type: Sandy loam, irrigated (Solid set system) Planting Dates: May 18-23, 1979 Harvest Dates: September 27,- October 3, 1979 Experimental Design: Treatments applied by aerial, ground and irrigation methods were laid ost in two adjacent fields in a randomized design. The ground and aerial treatments were replicated but irrigation treatments were not. Plots varied in size. Those treated by the irrigation method were 4.5 acres those treated with a boom sprayer were 3.5 acres and those treated by air were 10 acres. Application Methods: (A) Irrigation - Solid set system with 31 inch risers spaced 40 feet apart in line and 60 ft. apart between lines. Sprinklers were Rainbird # 1400 with 1/8 in. nozzles. The operating pressure was 80 psi at pump and 65 psi (average) at the nozzle. The nozzle output was estimated to be 3.71 gals/min and the total volume of application 1450 gals/A. Fungicides at a 20x spray concentration were pumped into the irrigation system at 120 psi using a gasoline powered garden sprayer and a fertilizer injector with a 1/4 inch orifice. With this system it took approximately 20 minutes to treat 1.8 acres. A red dye was used to make this determination. (B) Ground Sprayer: 10 row brush boom sprayer with flat fan nozzles. The operating pressure was 40 psi and the volume of application 20 gals/A. (C) Aircraft: . Biplane Ag-Cat Model A with a boom and 46 hollow cone nozzles oriented 45° backward. The operating pressure was 40 psi and the volume sprayed 5 gals/A. Treatment: Fungicides (see Table) Sprays applied 5-7 days between July 7 and August 18, 1979; 8 applications Insecticides - All plots received an in-furrow application of Temik 3 lb ai/A at planting. After midseason Thiodan 1 1/2 qts/A applied every 14 days with all fungicide treatments except Redomil applied by fungigation. Pirmore 8 oz/A applied in place of Thiodan. Data Summary: Collection: Treatments were rated for foliage diseases, yield and tuber rot within subplots. Each subplot consisted of a transect 50 feet wide extending across the plot. There were 4 subplots in non replicated plots. Replicated plots had two subplots per replication. The predominent disease on the foliage was early blight. All treatments except those containing only Ridamil controlled this disease. Of the fungigation treatments Du-ter, Bravo and Super Tin where the most effective. Super Tin was better than all other treatments for control of Botrytis Blight. It also had the highest yields of US #1 potatoes. Late blight infection was very light and symptoms were not noticeable in the unsprayed control until the end of the season. There was also virtually no tuber rot except in a few of the ground sprayed treatments. 1979 RESULTS: APPLICATION OF FUNGICIDES FOR CONTROL OF POTATO DISEASES BY SOLID SET IRRIGATION BY GROUND SPRAYER BY AIRCRAFT AVERAGE YIELD CWT/A2 US #1 FOLIAR DISEASE INDEX1,2 BOT. BLIGHT FOLIAR DISEASE INDEX1,2 L. BLIGHT FOLIAR DISEASE INDEX1,2 E. BLIGHT SPRAY SCHEDULE METHOD OF APPLICATION AVERAGE YIELD CWT/A2 B GRADE % 2, 3 TUBER ROT 7 DAYS IRRIGATION 1.8a 7 DAYS IRRIGATION 1.7a 7 DAYS IRRIGATION 2.2abc 7 DAYS IRRIGATION 2.8 bcd 0.1a 0.1a 0.1a 0.1a 1.7 bc 368.5ab 81.2a 0.0a (trace) 1.3 b 0.8a 338.0 bc 44.6 bc 0.4a 398.4a 32.3 c 0.0a 2.5 de 375.4ab 81.4a 0.0a (trace) TREATMENT BRAVO 500 4F 2PT/A DU-TER 47 1/2W 8OZ/A SUPER TIN 4L 9OZ/A MANEX 4F 4 1/2 PT/A RIDOMIL 2E 1/4 lb Ai/A 14 DAYS IRRIGATION 6.6 f 0.0a 2.2 d 332.3 be 30.2 c RIDOMIL 2E 3/16 LB AI/A 14 DAYS RIDOMIL 2E 3/16 LB AI/A 14 DAYS AIR 4.7 e GROUND 4.2 e 0.0a 0.1a 2.8 e 362.1ab 97.3a 2.2 d 294.7 cd 54.1 be 2.4 b 0.3a 0.1a RIDOMIL 2E + DITHANE M-45 80W 1/10 LB AI + 1 LB/A DITHANE M-45 80W 2LB/A 7 DAYS GROUND 2.7 bcd 0.1a 2.7 e 300.1 cd 45.8 be 1.8ab 7 DAYS AIR 2.0ab 0.1a 2.0 c 386.1ab 34.5 c 0.0a (trace) DITHANE M-45 80W 2LB/A 7 DAYS NO TREATMENT —— LSD .05 empty table cell GROUND —— empty table cell 2.2abc 6.8 f .6 0.5a 2.7 b 1.2 2.5 de 3.7 f .4 360.6ab 251.7 d 56.6 77.1ab 78.8a 32.5 2.8 b 5.8 c 2.3 1 DISEASE INDEX 0= NO INFECTION -10=100% INFECTION 2 SMALL LETTERS INDICATE TREATMENTS THAT DO NOT.DIFFER SIGNIFICANTLY AT THE 5% LEVEL ACCORDING TO THE LSD 1979 FIELD TRIALS ON POTATOES COMPARING APPLICATION OF FUNGICIDES BY CENTER PIVOT IRRIGATION AND BY AIRCRAFT Department of Botany and Plant Pathology H.S. Potter Investigator: H. S. Potter, Department of Botany and Plant Pathology Michigan State University, East Lanning, MI 48824 Cooperators: Allen Anderson, grower James Crosby, Montcalm County Extension Director Location: Allen Anderson Farm, Blanchard, MI Variety: Monona Disease and Pathogens: Early Blight - Alternaria solani Botrytis Blight - Botrytis spp. Soil Type: Sandy loam, irrigated (center pivot system) Planting Dates: May 23-27, 1979 Harvest Dates: October 3-5, 1979 Experimental Design: Application Method: An irrigated circle covering approximately 132 acres. In one half of the circle fungicides were applied thru the irrigation system and in the other half by aircraft. Treatments applied by the irrigation method (Fungigation) were randomized and replicated twice. The serial treatments were randomized but not replicated. Fungigation plots were 8 1/4 acres and those sprayed by air were 10 acres. (A) Irrigation Equipment - Gifford Hill electrically driven center pivot systems model # 360 with a 1300 ft. boom. The unit was designed to irrigate 132 acres and was regulated to cover 8 1/4 acres per hour. The operating pressure was 70 psi and the volume output 850 gals per minute. Fungicides as concentrate suspensions (12X) were injected into the system at the rate of 70 gals/hr using two double piston proportioning pumps (Inject - 0 - Meter; Duplex Electric Model # 69-1). Treatments were applied with .22 acre inches of water. (B) Aircraft - Biplane, Gruman Ag-Cat Model A with boom and 46 hollow cone nozzles (D 12-45) oriented 45° backward. Treatments were applied at 40 psi in 5 gals of water per acre. Treatments: (A) Fungicides (see Table) were applied on a 5 to 7 day schedule (based on Potato Late Blight Forcast Recommendations) starting July 2, 1979 and ending September 18, 1979. (B) Insecticides - Temik applied in furrow at planting 3 lb ai/A and one foliar spray each of Thiodan 1 1/2 qts/A and Monitor 1 qt/A applied overall by air. Data Collection: Foliage disease index ratings, yield and incidence of tuber rot were taken within 50' X 50' subplot. There were four of these subplots for each of the unreplicated aerial treatments and two in each replications of the fungigation treatments. Results: See table. Summary: All treatments whether applied by air or by the irrigation method significantly reduce disease infections. Dithane M-45, Du-ter and Difolatan thru the irrigation system appeared to give the best control of early blight. These treatments also had the highest yeilds of US #1 potatoes. Bravo 500 had the least amount of Botrytis infection. 1979 RESULTS: APPLICATION OF FUNGICIDES FOR CONTROL OF POTATO DISEASES BY CENTER PIVOT IRRIGATION AND BY AIRCRAFT TREATMENTS METHOD OF APPLICATION DISEASE INDEX 1, 2 FOLIAGE DISEASE INDEX 1, 2 BOTRYTIS BLIGHT EARLY BLIGHT FOLIAGE DIFOLATAN 4F 3PT/A AIR 2.1 c DIFOLATAN 4F 3PT/A IRRIGATION 1.7abc DUTER 10 OZ/A AIR 1.8 bc DUTER 10 OZ/A IRRIGATION 1.4a DITHANE M-45 80W 2 LB/A IRRIGATION 1.2a BRAVO 500 4F 2PT/A IRRIGATION 2.1 bc NO TREATMENT LSD .05 — — empty table cell 5.5 d . 5 AVERAGE YIELD CWT/A2 AVERAGE YIELD CWT/A2 US # 1 B GRADE % 2, 3 TUBER ROT 341.6 c 62.8 bc 1.1a 376.4a 366.8 b 384.6a 390.8a 365.5 b 62.1 bc 79.2 b .6a .7a 75.3 bc .7a 69.6 bc 56.2 c .3a .4a 3.4 d 2.0 bc 3.1 d 1.6ab 2.1 bc 1.2a 3.8 e 309.2 d 101.6a 2.4 b .5 20.4 21 .2 .9 1 Disease index 0=no infection - 10=100% infection 2 SMALL LETTERS INDICATE TREATMENTS THAT DO NOT DIFFER SIGNIFICANTLY AT THE 5% LEVEL ACCORDING TO THE LSD TEST BACTERIAL SOFT ROT, FUNGAL ROTS INCLUDING LATE BLIGHT. 3 POTATO INSECT CONTROL STUDIES A. L. Wells Department of Entomology A. Soil Insecticide Evaluation Studies A plot to evaluate 22 different treatments including combinations of experimetal and registered insecticides on soil insects was conducted. At the Comden Farm adjacent to the Montcalm Experimental Farm in Montcalm County. The plot was located in a field which has been out of production several years and had become established with weeds and grasses. An early inspection of the area indicated soil insects, especially wireworms were prevalent. The treatments were applied in six replications of paired 25 foot rows in a randomized black design. The outside and every third plot was left untreated so the insect damage in each treated plot could be compared with an adjacent untreated plot. This plot layout was selected to assume adequate evaluation of the data since past research indicated that soil insect populations are seldom evenly distributed over an area. Eight foot alleys were left untreated between the ends of the replicated plots. The broadcast applications were distributed as granules or in sprays at forty gallons of water to the soil surface and incorporated immediately with a double disc to a depth of 6-8 inches. The treatments were made on May 14 and they planted the following day. The potatoes were planted with a two row planter leaving the seed furrow open for application of the band or in furrow treatments after which they were covered with a disc and weeder attachment on a tractor. The NC-6897 seed treatment was applied dir­ ectly to the cut seed and planted by hand prior to covering. Wisconsin 718, a round white variety of potato, was used as cut seed in the study. Recommended fertilizer, herbicide and fungicide programs were followed during the study. The potato plants in the eight foot alleys between the ends of plots were pulled by hand during mid season so the untreated potato plants and tubes would not interfere with the sampling of the treated plots. A vine killer was applied prior to harvest to facilitate the use of the plot mechanical harvester. The plots were harvested on October 2nd. and 3rd. and placed in bags which were then labeled and taken to the research building at the Montcalm Research Farm. The B size tubers (up to 1 7/8" diam.) were sorted with the plot harvester and kept separate in the labeled bags. To determine the effects of the soil treatments on the potato yields and quality the tubers were sorted by size (i.e. B’s = up to 1 1/8", A's = 1 7/8 to 3 1/4" and over 3;/4) and according to insect damage (1- no wireworm scars, 2 - minor surface feeding only, 3 - extensive damage, grub and cutworm damage. The tubers in each of the size and damage rating classes were counted and weighed for adequate analysis of the data. Samples of tubers from three replications of the treated plots were saved to determine their specific gravity. The plot data are presented in Table 1. Results Although the primary objective of the study was to obtain control data for white grub infestations the populations were too low to show differences between any of the treatments. The populations of wireworms appeared to be evenly dis­ tributed over the study area since the damage rating to the tubers was consistent in all of the untreated plots. The seed treatment and all of the broadcast soil treatments with the exception of the Diazinon treatment reduced the wireworm dam­ age to the tubers when compared' with the adjacent untreated plots. All of the treated plots produced more tubers than the adjacent untreated plots which indi­ cate early season protection of the plant is essential for a higher potential yield. The combination treatments of Temik or Furadan with any of the broadcast applications provided better wireworm protection than any of the treatments alone. The use of the systemic also provided higher yields and better size than did the other non-systemic plots. If a full foliar program had been applied this differ­ ence would probably not have been as great. B. Foliar Insecticide Evaluation Fourteen soil systemic and foliar insecticides including both registered and experimental compounds were evaluated on potatoes in 1979. The treated plots consisted of paired 25 foot rows randomized in three replications using Russet Burbank seed. The rows were left open during the planting operation so the band applications of the systemic could be made prior to covering. A second applicat- ion of granules was sidedressed to the Sisyston plot at the time of hilling. Rec- ommended fertilizer, herbicide and fungicide programs were followed during the study. Foliar applications were started on June 26 and re-applied on July 12 and August 22. A CO2 sprayer delivering 50 gallons per acre was used to apply the foliar insecticides. The foliar insect populations were samples with an insect net on July 12, 25, August 1 and 22 at which time the plots were rated for vigor and insect damage. The data are presented in Table 2. Vine killers were applied in September and the plots were harvested on October 1. The yields, size grades and specific gravity of the tubers are given in Table 3. Results The foliar insect populations on the plots were very low during the study except for the Colorado potato beetle. If the plots could have been treated more often during late July and early August the data would have shown more differences between the treatments. The plot ratings in late August indicate that the system- ics and certain foliar applications protected the plots more than others. These plot ratings weren’t reflected in the yields, however, indicating the plants had matured earlier in some plots. The Temik treatment provided the highest yield in the study, indicating additional nematode protection to the plants. Table 1. Yields and insect tuber damage data from soil insect research plot, Montcalm Bounty, 1979. Planted: May 15; Harvested: October 2 and 3, 1979. Material and Placement NC-6897 76W Seed Trt Untreated —— Rate ai/A Yield/A 4 oz ai/ 317 cwt 100 1b — 245 NC-6897 76W Untreated NC-6897 76W + Temik 15G Untreated NC-6897 76W + Furadan 10G Untreated — Mocap 6EC Untreated Mocap 6EC + Temik 15G Untreated Dyfonate 10G Untreated Dyfonate 10G + Temik 15G Untreated Dyfonate 4E Untreated — — BrdCst — Brdcst Band —— Brdcst Band Brdcst — Brdcst Band Brdcst — Brdcst Band Brdcst —— 4 1b — 4 1b 3 1b — 4 1b 3 1b — 3 1b — 3 1b 3 1b — 4 1b — 4 1b 3 1b — 4 1b — Dyfonate 4E 4 1b + Temik 15G 3 1b Untreated — — Brdcst Band 333 255 386 249 387 245 269 273 368 269 272 270 375 258 255 245 379 268 Percent tubers Percent tubers by Grade Size by Grade Size B,s A's 4% 79% Percent tubers by Grade Size Over 17% Spec. Grav. 1.069 Total tubers 2064 Damage Damage Rating Rating(per cent by weight) (per cent by weight) 1 70% 2 14% Damage Rating (per cent by weight) 3 16% Damage Rating (per cent by weight) Grub, et al 0.2% 2 4 3 2 3 3 3 5 4 2 3 4 3 3 3 4 5 4 3 79 71 69 64 75 64 69 77 70 65 68 77 75 68 69 81 74 66 73 19 — 1.070 25 28 — 1508 1905 1395 1.071 — 2031 1462 1.070 — 34 22 33 28 18 26 — 1.068 1.072 33 29 — 1.067 19 22 — 29 28 — 15 21 1.071 1.065 — 30 24 1.072 — 2048 1331 1687 1428 1893 1481 1719 1504 2056 1451 1658 1433 2103 1576 36 73 40 79 55 85 33 80 48 90 44 77 53 86 45 66 57 85 46 26 11 14 10 14 8 17 9 12 6 10 9 12 7 16 13 14 6 15 37 16 45 11 31 7 50 11 40 4 45 14 34 7 39 21 29 0.2 0.5 0.4 0.1 0.2 0.1 0.2 0.3 0.2 0.2 1.0 0.1 1.0 0.2 0.4 0.2 0.6 9 39 contd. 0.3 0.3 Table 1, contd. Material and Placement Brdcst Dyfonate 4E Band + Furadan 10G Untreated — Brdcst — Dasanit 15G Untreated Rate ai/A 4 lb 3 lb — 5 lb — Yield/A 362 cwt 257 329 278 Dasanit 15G + Temik 15G Untreated Diazinon 4E Untreated Diazinon 4E + Temik 15G Untreated Diazinon 4E + Furadan 10G Untreated Lorsban 4E Untreated Lorsban 4E + Temik 15G Untreated Temik 15G Untreated Furadan 10G Untreated Control Untreated Brdcst Band — Brdcst — Brdcst Band —— Brdcst Band — Brdcst — Brdcst Band —— Band Band — — —— — — 5 lb 3 lb — 4 lb — 4 lb 3 lb — 4 lb 3 lb — 4 lb — 4 lb 3 lb — 3 lb -- 3 lb — -- 387 279 259 219 394 264 367 292 293 263 396 270 381 244 340 244 292 258 Percent tubers by Grade Size B’s Percent tubers by Grade Size A's Percent tubers by Grade Size Over Spec. Grav. Total tubers Damage Rating (per cent by weight) Damage Rating (per cent by weight) Damage Rating (per cent by weight) 2 3 Grub, et al 6% 20 16 18 7% 43 19 48 0.1% 0.6 0.03 0.4 Damage Rating (per cent by weight) 1 87% 36 65 34 4% 3 3 3 3 3 5 4 2 3 2 2 4 3 4 3 3 4 3 3 3 3 69% 75 68 78 64 66 72 74 63 73 63 70 73 68 63 71 60 72 68 67 70 72 27% 22 29 19 33 31 23 22 35 24 35 28 23 29 33 26 37 24 29 30 27 25 1.071 — 1.069 — 1.073 — 1.068 — 1.070 — 1.070 — 1.067 — 1.070 -- 1.069 — 1.069 — 1.060 — 2026 1553 1815 1612 2050 77 1521 43 60 58 1674 1302 2052 1526 1913 1597 1778 1400 2147 1510 1512 1426 1847 1283 1599 1471 72 44 78 31 66 37 78 44 63 45 69 32 45 48 11 12 17 9 12 16 10 15 14 13 11 10 13 15 13 17 17 15 12 44 23 32 16 39 12 53 20 49 11 45 24 40 18 51 38 37 0.2 0.9 0.2 0.6 0.1 0.7 0.2 0.5 0.0 1.3 0.3 0.9 0.1 0.7 0.1 0.3 0.2 0.4 contd. Table 1, contd. Material and Placement Control Untreated — — Rate ai/A — — Yield/A 26cwt 249 Percent tubers by Grade Size B’s 3% 3 Percent tubers by Grade Size A ’s 68% 29% Percent tubersby Grade Size Over 25 — 71 Damage Rating (per cent by weight) Spec. Grub,et al Grav. 1.0681479 36% 11%52% 0.5% 0.2 Damage Rating (per cent by weight) Total tubers Damage Rating 1446 (per cent by weight) 1 Damage Rating (per cent by weight) 2 40 3 15 45 1 Grade sizes: B - to 1 7/8 in; A - 1 7/8 to 3 1/4 in.; Over - over 3 1/4 in. 2 Insect Damage Rating: 1 - No wireworm scars; 2 - Minor surface feeding; 3 - Extensive damage; Other - Grub, cutworm, etc. Table 2. Foliar Insects Sampled form Insecticide Evaluation Study. d e t c e l l o C s t c e s n o I t a l a t t o o P 2 r e p p o h f a e l Treatment1 T d e t c e l l o C s t c e s n I r e l a t t s o 2 A T r e p p o h f a e l d e t c e l l o C s t c e e s n l I t t l a i t p o T 2 S s g u b d e t c e l l o C s t c e s n I l a a e t o l T 2 F s e l t e e b d e t c e l l o C s d t c e e h s n s I i n l a r t a o 2 T T g u b t n a l P ) t l u d A ( d e t c e l l o C o t s a t c t e o s P n I l . a l t o o 2 C T ) e a v r a L ( d e t c e l l o C o t s a t c t e o s P n I l . a l t o o 2 C T d e t c e l l o C s s t c r e o s t n a I d l a e t o r T 2 P s e t i s a r a P e l t e e B e l t e e B s d i h p Total Insects Collected2 A NC-6897 0.5 lb 27 NC-6897 1.0 lb 20 Vydate 1.0 lb Vyd + Lan Pounce 0.1 lb Pounce 0.2 lb Ambush 0.2 lb Pydrin 0.2 lb 23 21 28 25 35 16 BFN 4886 1.0 lb 67 Monitor 0.75 lb 27 Thiodan 1.0 lb 40 Temik 3.0 lb Furadan 3.0 lb 8 9 Disyston 3+3 lb 19 Untreated Untreated 21 28 9 10 4 7 9 5 7 5 16 6 9 2 13 6 10 7 2 2 3 2 4 5 4 3 7 8 3 2 1 3 3 6 3 4 1 3 3 2 1 3 5 1 11 2 1 0 0 2 15 13 11 19 16 15 7 8 13 17 9 7 14 17 17 12 56 26 44 21 13 7 13 7 21 11 23 5 40 8 40 32 22 3 44 22 42 57 35 20 38 49 45 4 2 42 70 101 23 3 1 5 114 26 62 5 83 71 54 1 3 27 137 123 13 11 8 17 8 10 11 4 10 11 8 12 14 7 14 11 Plot Rating3 3.0 3.7 2.0 2.0 3.3 3.3 3.3 3.0 4.0 4.0 3.7 1.6 2.7 3.0 4.0 4.3 1 Refer to Table 3 for Formulations and rates 2 3 Total of 30 sweeps (10 sweeps per replication) on July 12, 25, Aug. 1 and 22 Plot ratings made on Aug. 28 for Plant vigor and Maturity: 1 - Vigorous growth to 5 - Moot of plants dead or drying down. Table 3. Yield data and Specific Gravity from Foliar Evaluation Study Material and Formulation Fison NC-6897 Fison NC-6897 Vydate 2L Vydate 2L + Lannate 1.8L Pounce 3.2EC Pounce 3.2EC Ambush 2EC Pydrin 2.4EC Rate/A (Tox) 0.5 lb 1.0 lb 1.0 lb 0.5 lb 0.5 lb 3.2 lb 0.2 lb 0.2 lb 0.2 lb Boots BFN 4886 25W 1.0 lb Monitor 4WDL Thiodan 3EC Temik 15G Furadan 10G 0.75 1.0 lb 3.0 lb 3.0 lb Disyston 15G 3.0 + 3.0 lb Untreated Untreated — — Percent by Grade Size Percent by Grade Size Percent by Grade Size Percent by Grade Size Yield/A 340 cwt B’s 5% A’s 80% 10 oz 9% 328 342 367 318 321 321 333 292 303 332 405 351 332 321 282 7 5 5 7 6 8 5 9 7 6 4 4 5 5 8 80 73 78 82 76 77 80 76 73 79 71 69 73 78 82 4 5 6 2 4 5 4 4 7 7 8 11 7 6 1 Off- type 6% 9 17 11 9 14 10 11 11 13 8 17 16 15 11 9 Spec. Grav. 1.076 1.075 1.076 1.078 1.072 1.076 1.075 1.075 1.075 1.074 1.076 1.077 1.075 1.075 1.076 1.075 CONTROL OF THE ROOT-LESION NEMATODE (PRATYLENCHUS PENETRANS) ASSOCIATED WITH NAVY BEANS G.W. Bird and AP. Elliott Department Entomolgy Seven nematicides were evaluated. Each treatment was replicated 5 times in a randomized block design on a sandy clay loam soil at the Michigan State University Montcalm Experimental Farm in Entrican. Each plot consis- ted of 4 rows 6.1m in length and 0.9m apart. All nematicides were applied in 0.2m bands at the time of planting on June 5, 1979 (accumulated degree days at base 50F (DD50 = 372). The foliar Vydate spray was applied 3 weeks after planting (DD50 = 705). Soil and root samples for nematode analy­ sis were taken at 6 intercals during the growing season. The centrifugal- flotation and shaker techniques were used to determine population densities of P. penetrans in soil and root samples, respectively. The two center rows of each plot were harvested on September 21, 1979 (DD50 = 2196), and the weight of bean seeds from each plot was recorded. There were no significant differences (P = 0.05) in soil population densities among plots at the time of planting (DD50 = 372). Soil population densities of P. penetrans were significantly reduced (P = 0.05) throughout the season by all nematicide treatments. Root population de^sties were signi- ficantly reduced (P = 0.05) by Vydate L at 1.0 lb a.i. per acre plus 1.0 lb a.i. foliar spray, and by all rates of Temik 15G except - the lowest rate (0.5 lb . a.i. per acre). Dry bean yields were significantly increased (P = 0.05) by treatments of Vydate at 1.0 lb a.i. plus 1.0 lb a.i. foliar spray per acre and Temik 15 G at 1.0, 1.5 and 2.0 lb a.i. per acre respectively. Effect of Nematicide Treatments on Pratylenchus penetrans and Yield of Dry Beans Pratylenchus Penetrans at DD50* Pratylenchus Penetrans at DD50* Pratylenchus Penetrans at DD50*No./100cm3 Pratylenchus Penetrans at DD50*No./g root Pratylenchus Penetrans at DD50* Treatment, Formulation and Rate Per Acre Yield (cwt/A) Pratylenchus Penetrans at DD50* No./100cm3 soil 372 Pratylenchus Penetrans at DD50* No./100cm3 soil 873 Pratylenchus Penetrans at DD50*No./100cm3 soil 1144 Pratylenchus Penetrans at DD50* No./100cm3 soil1568 No./100cm3 soil 1737 No./100cm3 soil 2110 soil 2196 tissue 873 No./g root tissue 1144 Pratylenchus Penetrans at DD50*No./g root tissue 1568 Pratylenchus Penetrans at DD50*No./g root tissue 1737 Pratylenchus Penetrans at DD50*No./g root tissue2110 Pratylenchus Penetrans at DD50* No./g root tissue 2196 Check. ** 13.91a Vydate L 1.0 lb a.i./ A. 16.76ab 117a 89a 41b 15a 56b 12a 48b 12a 125b 20a 72b 17a 250b 85a 145c 200b 48c 328b 103b 16a 76a 6ab 17a 9a 25b 4a Vydate L 1.0 lb a.i./A plus 1.0 lb a.i./A foliar spray. Terr-o-cide 54-45 1.0 gal./A Temik 15G 0.5 lb a.i./A. Temik 15G 1.0 lb a.i./A. Temik 15G 1.5 lb a.i./A Temik 15G 2.0 lb a.i./A 22.21bcd 98a 20a 7a 10a 34a 13a 80a 17a 12a 6ab 12a 16a 4a 16.52ab 132a 18a 14a 13a 20a 16a 54a 72b 120ab 24ab 4a 8a 11ab 19.14abc 121a 35b 17a 33 ab 24a 19a 122a 41a 104ab 37bc 45a 20a 14ab 21.29bcd 116a 12a 11a 20a 10a 12a 51a 15a 12a 16ab 18a 14a 24.14cd 25.06d 111a 122a 6a 7a 8a 5a 13a 9a 6a 3a 10a 38a 5a 34a 8b 4a 6a 4a l0ab 10a 3a 9a 9a 5a 5a 3a 3a *DD50 = accumulated degree days (base 50F) = Ʃ[(min. temp, + max. temp)/2 - 50F)] **Column means followed by the same letter are not significantly different (P = 0.05) according to the Student Newman Keuls multiple range test. CONTROL OF THE ROOT-LESION NEMATODE (PRATYLENCHUS PENETRANS) ASSOCIATED WITH FIDE DRY BEAN VARIETIES G.W. Bird and A.P. Elliott Department of Entomology Temik 15G at 2.0 lb a.i. per acre was evaluated for control of P. penetrans on dry beans. Five bean cultivars, Sanilac, Seafarer, Tuscola, Montcalm Kidney and Charlevoix Kidney were planted in a randomized block design of five replicates of plots treated with Temik at 2.0 lb a.i. per acre and five replicates of control plots without Temik 15G. Each plot con­ sisted of 4 rows 6.1m in length and 0.9m apart. Temik 15G was applied in 0.2m bands at the time of planting on June 5, 1979 (accumulated degree days at base 50F (DD50 = 372). Soil and root samples for nematode analysis were taken at 6 intervals during the growing season. The centrifugal-flotation and shaker techniques were used to determine soil and root population den- sities respectively. The two center rows of each plot were harvested on October 15, 1979 and the weight of bean seeds from each plot was recorded. There were no significant differences (P = 0.05) in population densities among plots at the time of planting (DD50 = 327)). Soil and root population densities were significantly reduced (P = 0.05) by Temik 15G at DD50 = 873. Compared to all other varieties, P. penetrans densities were highest on Sani­ lac and Mooncalm kidney beans at DD50 = 1737 Temik 15G at 2.0 lb a.i. per acre significantly increased (P = 0.05) the yield of all varieties. Effect of Aldicarb (Temik 15G) for Control of Pratylenchus penetrans on Five Dry Bean Varieties Bean Variety, Treatment, Formula­ tion, and Rate Yield (cwt. /A) Pratylenchus Pratylenchus Penetrans Pratylenchus Penetrans at Pratylenchus Penetrans at DD50*No./100cm3 Pratylenchus Penetrans at DD50*No./g Penetrans at Pratylenchus Pratylenchus Penetrans at DD50*No./100cm3 soil873 Pratylenchus Penetrans at DD50* No./100cm3 soil 372 Pratylenchus Penetrans at DD50*No./100cm3 soil1144 Penetrans at DD50*No./100cm3 soil 1568 at DD50*No./100cm3 soil 1737 DD50* No./100cm3 soil2110 soil 2305 DD50*No./g root tissue 1144 Pratylenchus Penetrans at DD50* No./g root tissue1568 Pratylenchus Penetrans at DD50*No./g root tissue 1737 Pratylenchus Penetrans at DD50*No./g root tissue2110 Pratylenchus Penetrans at DD50* No./g root tissue 2305 root tissue 873 12.46a** 134a 16.76b 17.99b 10.30a 18.53b 126a 116a 128a 133a 19.91b 131a 25.06c 168a 24.21c 125a 25b 16ab 15ab 18ab 10a 5a 4a la 14a 5a 12a 19a 4a 2a 8a 2a 104c 39b 142c 518c 130b 320b 249b 448b 134a 74c 88bc 11a 40ab 338bc 84bc 23a 44ab 324bc 51bc 17a 71b 332bc 32ab 18a 53ab 184ab 113b 174b 138b 45a 36a 15a 82a 56a 37ab 40a 62a 27a 9a 162a 136a 26a 80a 408b 490b 9a 179a 152a 63bc 34ab 12a 6a 4a 4a 2a 5a 14a 34a 10a 18a 4a 18a 4a 5a 18a 2a 8a 17a 15a 6a 2a 3a 8a 1la 8a 5a 4a Sanilac. Seafarer. Tuscola. Montcalm Kidney. Charlevoix Kidney. Sanilac + Temik 15G 2.0 lb a.i./A. Seafarer + Temik 15G 2.0 lb a.i.A. Tuscola + Temik 15G 2.0 lb a.i./A. Montcalm Kidney + Temik 15G 2.0 lb a.i./A Charlevoix Kidney + Temik 15G 1.0 lb a.i./A. 4a 5a 4a 2a 22.29c 149a 2a 4a 11a 7a 12a 16a 25.83c 140a 5a 2a 12a 4a 7a 15a 5a 2a 22a 3a 16a 9a 10a 5a 5a 3a 2a *DD50 = accumulated degree days base 50ºF = Ʃ[(min. daily temp. + max. daily temp) /2 - 50 F] **Column means followed by the same letter are not significantly different (P = 0.05) according to the Student - CONTROL OP THE ROOT-LESION NEMATODE (PRATYLENCHUS PENETRANS) ASSOCIATED WITH SOYBEANS G.W. Bird and A.P. Elliott Department of Entomology Five nematicide treatments were evaluated. Each treatment was repli­ cated 5 times in a randomized complete block design on a sandy clay loam soil at the Michigan State University Montcalm Experiment Farm in Entrican. Each plot consisted of 4 rows 6.1m in length and 0.9m apart. All nematicide treatments were applied in 0.18m bands at the time of planting on June 5, 1979. (accumulated degree days at base 50 F (DD50 = 372). Soil and root samples for nematode analysis were taken at 6 intervals during the growing season. The centrifugal-flotation. and shaker techniques were used to determine soil and root population densities, respectively. Yield data was obtained from the two center rows which were harvested on October 22, 1979 (DD50 = 2378). There were no significant differences (P = 0.05) in soil population den­ sities among plots at the time of planting (DD50 = 372). Soil and root popu­ lation densities were significantly reduced (P = 0.05) throughout the season by all nematicide treatments. Soybean yields were significantly increased (P = 0.05) with Vydate L at 1.0 lb a.i. per acre and Temik at 1.0 and 2.0 lb a.i. per acre. Effect of Nematicide Treatments on Pratylenchus penetrans and Yield of Soybeans Pratylenchus Penetrans at Pratylenchus Penetrans at DD50* Pratylenchus Penetrans at DD50*No./100cm3 Pratylenchus Penetrans at DD50*No./g root Pratylenchus Penetrans Pratylenchus Penetrans at DD50*No./100cm3 soil1144 Pratylenchus Penetrans at DD50* No./100cm3 soil1568 DD50*No./100cm3 soil 1737 No./100cm3 soil 2110 soil 2378 at DD50* No./g root tissue1144 Pratylenchus Penetrans at DD50*No./g root tissue1568 Pratylenchus Penetrans at DD50*No./g root tissue1737 Pratylenchus Penetrans at DD50*No./g root tissue2110 Pratylenchus Penetrans at DD50* No./g root tissue 2378 Treatment, Formulation and Rate Yield (cwt/A) Check. 16.45a Vydate L. 1.0 lb a.i./A. 22.34b Vydate L. 1.0 lb a.i./A + 1.0 lb a.i. foliar spray. 19.9 lab Nemacur 15G .1 oz a.i. / 1000 row ft 7" band 19.52ab Temik 15G 1.0 lb a.i./A. Temik 15G 2.0 lb a.i./A. 21.14b 23.45b Pratylenchus Penetrans at DD50* No./100cm3 soil 372 Pratylenchus Penetrans at DD50* No./100cm3 soil 873 120a** 32b 65a 73a 95a 107a 94a 7a 4a 4a 3a 3a 13b 2a la 2a 5a 2a 36b 16a 19a 15a 2a 2a 4a 7a 3a 4a 50b 4a 62b 10a 213b 46a 23a 108a 49b 8a 6a 94b 34a 126c 216b 21ab 26a 24a 52b 58a tissue 873 166b 40a 50a 29a 58a 46a 11a 25a 49ab 57a 14a 18a 16a 48a 23a 30a 4a 6a 38a 11a 3a 19a 24ab 18a 9a 3a 2a 3a la 2a *DD50 = accumulated degree days (base 50F) = Ʃ[(min. daily temp. + max. daily temp.)/2 - 50F] **Column means followed by the same letters are not significantly different (P = 0.05) according to the Student Newman Keuls multiple range test. INFLUENCE OF EXPERIMENTAL NEMATICIDES ON PRATYLENCHUS SPP. AND ON YIELD OF FIELD CORN Department o£ Entomology and Department o£ G.W. BZW and E. Caswell Botany and Plant Pathology Four nematicides were evaluated using ten different treatments. Each treat­ ment was replicated five times in a randomized block design on sandy clay loam soil (66.4% sand, 11.08% silt, 22.5% clay) at the Michigan State University Montcalm Experimental Farm located in Entrican, Michigan. Each plot was four rows wide (86 cm rows) and 9.2 m in length. A fertilizer treatment con­ sisting of 400lb/A 6-24-24 was applied on 5/25/79, with an additional 75 lb/A of actual Nitrogen side dressed on 6/25/79. Granular nematicides were applied in a .2m band at planting. Liquid nematicides wem applied broadcast at plant, with the exception of Vydate which was applied in a .2m band. A Vydate foliar spray was applied on 6/22/79 for one treatment. Dyfonate was added to control com rootworm. Soil samples were taken prior to planting, and at 3 intervals during the growing season. The last soil sample was taken post-harvest (11/15/79). The centrifugal-flotation and shaker techniques were used to determine Pratylenchus spp. populations in soil and roots, respectively. The com was harvested and weighed on 11/08/79. There were no significant differences (P = 0.05) in nematode densities among the plots prior to planting. During the course of the growing season visual in­ spections of the plots revealed no differences between treatments. The nematode densities within the root were significantly higher in the check with Dyfonate treatment, throughout the growing season. There were no significant differences in yield (either weight or number of ears per plot) among treatments. Table 1. The Effect of Experimental Nematicides on Pratylenchus spp. and Field Corn Yield. Pratylenchus spp. per Pratylenchus spp. per Pratylenchus spp. per sampling Pratylenchus spp. per sampling period Pratylenchus spp. per sampling Pratylenchus spp. sampling period No/100cc soil 8/16 period No/100cc soil 10/11 Treatment, formulation, application rate Check Yield weight of ears (kg) 14.5al Yield No. of ears 83a Check + Dyfonate 1.0 lb a.i./A 13.9a Vydate L 1.0 lb a.i./A + Dyfonate 1.0 lb a.i./A Vydate L 1.0 lb a.i./A + Dyfonate 1.0 lb a.i./A + Vydate L foliar application 1.0 lb a.i./A Mocap 10G 1.0 lb a.i./A Mocap 6EC 2.0 lb a.i./A Mocap 6EC 3.0 lb a.i./A Mocap 6EC 4.0 lb a.i./A Furadan 10G 1.5 lb a.i./A Amaze 15G 3.0 oz. a.i./lOOO ft. 14.6a 13.8a 13.9a 14.0a 14.3a 13.8a 14.0a 14.2a 81a 85a 87a 83a 77a 82a 80a 82a 84a sampling Pratylenchus spp. per sampling period No/100cc soil 5/24 periodNo/100cc soil7/03 42a 72a 41a 56a 46a 25a 52a 36a 44a 41a 48a 28a 48a 38a 47a 38a 34a 29a 44a 59a 2a 2a la 0a la 2a la 2a 2a 2a No/100cc soil 11/15 220a 158a 103a 96a 121a 94a 90a 46a 46a 24a 24a 15a 5a 17a 5a la 7a 7a period No/gm root tissue 7/03 per sampling period No/gm root tissue8/16 Pratylenchus spp. per sampling period No/gm root tissue 10/11 126ab 19ab 132ab 174b 29b 159b 8a 7a 66ab 14a 20a 21a 44a 13a 64a . 3a 3a 3a 2a 3a la 5a 26a 29a 39a 46a 14a 17a 56a 20a 179a 81a 1 Column means followed by the same letter are not significantly different according to the Student- Newman-Keuls Multiple Range Test (P = 0.05). LARGE SEEDED COLORED BEAM EVALUATION TRIAL Jerry Taylor and M.W. Adams Department of Crop and Soil Sciences Test 9218 This test of 15 large-seeded entries was planted on June 20, 1979, in 4 row plots, 16 feet long, rows 21" apart, in 4 replications, Eptam, pre-plant incor­ porated, was the only herbicide used. The nursery was sprinkle-irrigated six times at a rate of 1” per irrigation*, and hand-hoed twice during the growing season. No disease symptoms were observed. Growth was normal to unusually luxuriant for this location, although yields were not outstanding. Rainfall was adequate for June, very deficient for July, and barely adequate in August. The supplemental irrigation was needed to assure satisfactory yields. Table 1. Test 9218: Yields in lbs/A Clean Seed Adjusted to 15% Moisture, Montcalm Farm, 1979. Entry 70684 70688 70700 61144 5408 Alubia Charlevoix Manitou Montcalm Mecosta Redkloud Sacramento Michicran Cran 028 Valley Type L. R. Kid. L. R. Kid. L. R. Kid. empty table cell Large white Large white D. R. Kid. L. R. Kid. D. R. Kid. L. R. Kid. L. R. Kid. L. R. Kid. Cranberry Cranberry Great North. Mean Yield * 2238 2002 2149 1956 1911 1748 2204 1740 2269 2064 2216 2220 1904 2150 1842 *Differences among means not significant. Discussion This test was conducted primarily to compare the yield performance of 3 experimental light red kidney selections, namely, 70684, 70688, and 70700, with other kidney varieties. The objective has been to replace Mescota and Manitou with an earlier maturing light red possessing halo blight resistance. This test resulted in non-significant yields for all entries, although some had somewhat higher mean values than others. At least, the 3 strains of interest appeared to yield satisfactorily, and as good as standard varieties. A decision as to whether to increase seed of any of the experimentals will be made follow­ ing canning tests. *Plots irrigated on the following dates: July 20, 27, August 6, 14, 21, and 27. The bush Cran 028 continues to perform well, though not significantly better than the vine Michicran. There is a question concerning seed size of Cran 028. It may be somewhat smaller than the bean export trade would like, and for this reason we have not moved ahead to a final decision as respects its release. CORN HYBRIDS, PLANT POPULATION AND IRRIGATION E.C. Rossman and Keith Dysinger Department of Crop and Soil Sciences Performance data for 83 commercial corn hybrids evaluated in 1979 with irrigation and without irrigation are presented in Table 1 along with two and three year averages for those tested in 1978 and 1977. A total of 6 inches of supplemental water was applied during July and August. Bouyoucous soil moisture blocks were placed at 6, 12, 18 and 24 inch depths in both irrigated and unirrigated plot areas. Irrigation was applied When soil moisture reached 50% or less of water holding capacity at 6" level. Irrigated yields averaged 42.0 bushels more than unirrigated —108.5 vs 66.5, an increase of 63%. Hybrids ranged from 66.9 to 142.0 irrigated and 42.0 to 91.5 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. Eighteen of the 22 hybrids were in the highest yielding group for both irrigated and unirrigated plots. Irrigated Not Irrigated Garno S90 (2x) Pioneer 3901 (2x) Michigan 407-2x (2x) Super Crost 2350 (2x) Pioneer 3780 (2x) ADI 232 (2x) Asgrow RX2345 (2x) Blaney B 507 (2x) Select 3000 (2x) DeKalb XL 23 (2x) Customaize CFS 1000 (2x) Blaney B606 (2x) Migro M-2018X (2x) Michigan 5802 (2x) Pride 4488 (2x) Amcorn 7300 (2x) Great Lakes GL-552 (2x) Kaltenberg KX68 (2x) Cargill 924 (2x) Garno S90 (2x) Pioneer 3901 (2x) Michigan 407-2x (2x) Super Crost 2350 (2x) Pioneer 3780 (2x) ADI 232 (2x) Asgrow RX2345 (2x) Blaney B 507 (2x) Select 3000 (2x) DeKalb XL 23 (2x) Michigan 4122 (2x) Customaize CFS 1000 (2x) Blaney B606 (2x) Migro M-2018x (2x) Michigan 5802 (2x) Pride 4488 (2x) Amcorn 7300 (2x) Great Lakes GL-552 (2x) Kaltenberg KX68 (2x) ADI 325 (2x) Michigan 5912 (2x) Michigan 5922 (2x) Cargill 924 (2x) The correlation of irrigated with unirrigated yields was highly significant, .855, indicating that the hybrids tended to respond alike in both situations. During the 12-year period, 1968-1979, 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 12-year period, 1968-1979, are given in Table 2. The average yielding hybrids have yielded 49 more bushels when irrigated. The highest yielding hybrids have responded with 60 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 14.2% irrigated and 11.0% not irrigated. In 1978 there was twice as much lodging on irrigated plots and three times more lodging when irrigated in 1977. In most of the previous years 1968-1976, there was less lodging on the irrigated plots. Generally, stressed weaker plants on unirrigated plots have been more susceptible to lodging except during the past three years. In 1979, the highest lodging was 47% stalk breakage when irrigated compared to 42% unirrigated. The lowest lodging was only 1% irrigated and 0% unirrigated. Plant Population x Irrigation Five adapted hybrids at four plant populations irrigated and not irrigated have been grown in each of 12 years, 1968-1979, Table 3. Over the 12-year period, a population of 23,400 has given the highest average yield (168 bushels per acre) when irrigated while 19,200 has given the highest yield (108 bushels) without irrigation. The 23,400 population irrigated has given the highest yield in 10 out of the 12 years (1973 and 1979 being the exceptions). The 12­ year average increase due to irrigation has been 71 bushels per acre at the 23,400 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 populations. Table 2. Average, highest and lowest yields for corn hybrids irrigated and not irrigated for 12 years, 1968-1979. Year 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 AVERAGEempty table cell No. of Hybrids Tested AVERAGE Irrigated 83 73 74 80 75 76 72 72 56 64 63 56 109 144 125 156 154 112 114 157 163 144 146 136 139 AVERAGE Not Irrigated HIGHEST HIGHEST Irrigated Not Irrigated Irrigated LOWEST LOWE ST Not Irrigated 67 88 73 72 125 103 101 137 28 103 86 96 90 142 186 158 183 207 134 138 206 211 194 185 182 177 92 112 88 93 157 122 120 179 42 128 109 123 114 67 92 89 120 106 65 78 99 91 95 97 92 91 42 61 56 49 80 58 73 91 11 70 56 65 59 Table 3. Average yield at four plant populations irrigated and not irrigated for 12 years, 1968-1979. 15,100 15,000 Irrigated Not Irrigated 19,200 19,200 Irrigated Not Irrigated Irrigated 23,400 23,400 Not Irrigated 27,400 27,400 Irrigated Not Irrigated 77 92 74 72 136 100 97 132 37 91 91 114 94 140 164 152 174 183 130 134 187 189 144 158 169 160 87 110 81 84 164 111 116 159 35 112 109 130 108 138 175 160 181 196 135 128 191 191 158 173 193 168 83 100 70 81 151 98 106 149 20 93 96 107 97 131 165 150 161 172 120 108 161 181 151 148 178 152 78 94 69 68 146 94 102 144 11 85 86 89 89 Year 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 123 146 141 153 158 118 108 152 173 122 126 144 AVERAGE 140 Table 1 Hybrid (Brand-Variety) Hyland HL-2217 McKenzie 901 (3X) Hyland HL-2430 (2X) McKenzie 840 (3X) Michigan 280 (4X) Dairyland 1095 (2X) Select 1400 (MSX) Pioneer 3950 (3X) Hyland HL-2418 (2X) Hyland HL-2442 (2X) Michigan 333-3X (3X) Super Crost 1402 (2X) Migro M-0101 (2X) Funk G-4195 (3X) Michigan 3093 (3X) *+Garno S-90 (2X) P-A-G Exp. 263048 (2X) Blaney B302-wx (2X) Amcorn 4010 (2X) DeKalb XL13 (2X) Pride 2206 (2X) Michigan 3102 (2X) Super Crost 1950 (2X) *+Pioneer 3901 (2X) Migro M-0105 (2X) NORTH CENTRAL MICHIGAN Montcalm County Trial - Irrigated vs. Not Irrigated One, Two, Three Year Averages - 1979, 1978, 1977 Zone 3 % % Moisture % Bushels per Bushels per Bushels % Stalk % Stalk % Stalk % - - Moisture 3 yrs. 21 22 21 21 per acre 3 yearsIrrig Bushels per acre 3 years Not Irrig 91 61 94 61 acre 2 years Irrig Moisture1979 2 yrs. Bushels per acre 1979 Irrig % Stalk Lodging 1979 Irrig 90.8 52.8 Lodging 1979 Not Irrig - - 13 - - - - - acre 2 years Not Irrig 30.8 9.3 - 6.4 15.0 14.8 Bushels per acre 1979 Not Irrig 45.1 - - - - 32.8 21.2 - - 66.9 22.4 - - 72.3 46.2 - - - - 14.3 58.9 - - - - 11.0 22.5 - - 95.9 22.6 - - 70.9 42.0 - - - - 26.4 22.7 17.6 51.2 - - - - 14.1 22.7 - - 92.4 51.3 - - - - 17.8 22.7 - - 83.1 - - - 15.0 22.9 - - 110.8 60.2 - - - 38.0 23.1 - - 73.6 43.6 59.0 - - - - 12.7 23.1 - - 104.9 76 102.2 63.1 23.2 10.5 23.5 22 - 77.9 53 - - 27.5 44.8 63.1 72 23.5 9.0 102.0 72 23.7 - - 94.9 68.9 - - - 23.9 94.8 58.3 73 23.7 22 18.5 70 91 - - 13.8 23.7 23 - 123.0 91.5 7 73.6 - - - - 12.6 23.7 - - 112.8 - 73 - - 20.9 28.8 12 23.9 23 - 99.3 65.5 24.0 - - 90.3 54.7 - - - - 21.5 - 12.6 24.0 - - 94.3 66.4 - - - - 47.1 - 28.1 24.0 - - 112.4 63.0 - - - - 14.8 11.3 111.8 70.5 24.0 23 8.0 24.5 23 - 109.9 57.0 14.7 24.5 23 94.6 5.7 24.5 24 72.4 11.8 86 9.8 78 - - 15.2 98 7.2 85 17.5 7.9 12.6 6.7 42.1 7.3 11.5 17.3 9.7 13.5 11.7 146 138 150 125 118 85 119 109 133 115 115 116 - 111 139 149 124 136.1 98.9 22 23 23 8.3 10.3 7 17 7 - 11 - 6 11 4 12 73 81 93 81 25 25 26 Lodging 2 years Irrig — Lodging 2 years Not Irrig Stalk Lodging 3 yearsIrrig % Stalk Lodging 3 years Not Irrig - - — — - — 12 — - - 7 10 5 - 8 4 - 15 - - - 6 10 3 8 - - - - 12 — — - - - 5 - 8 - 8 - - - - - - 5 - 4 12 - - - - — - — 9 — - - - 5 5 - 6 - - - - - 4 - 2 6 Table 1 Continued. Select 2200 (MSX) Acco UC1151 (2X) DeKalb XL15 (2X) Super Crost 1692 (2X) McKenzie 950 (MSX) Great Lakes GL-452 (2X) Super Crost 1580 (2X) Super Crost 78015 (2X) Hyland HL-2440 (2X) Funk G-4224 (MSX) Pioneer 3958 (2X) *+Michigan 407-2X (2X) Migro HP16 (2X) P-A-G SX189 (2X) Dairyland 1099 (2X) *+Super Crost 2350 (2X) Customize CFS144 (2X) Michigan 3953 (3X) *+Pioneer 3780 (2X) *+ADI 232 (2X) *+Asgrow RX2345 (2X) *+Blaney B507 (2X) *+Select 3000 (2X) Funk G-4272 (3X) Migro M-2022X (2X) *+DeKalb XL23 (2X) +MicCigan 4122 (2X) Blaney B506 (2X) Aucorn 4100 (2X) *+Customaize CFS1000 (2X) Kaitenberg KX58 (2X) Acco UC2301 (2X) Kaltenberg KX54 (2X) Migro HP23R (2X) Migro HP20 (2X) 25 25 26 125 117 147 118 114 146 117 115 114 — - 73.1 — — — — 21.9 24.5 — - 109.6 70 — — 21.3 23 - 82.7 55.0 24.6 23 — 109.9 74 — — 7.5 73.4 24.9 72.8 11.7 23 104.2 24.9 78 75 110 69.9 — — — — 9.2 25.0 — — 104.9 62.3 — - — - 106.1 19.9 25.0 53.4 — — — — 19.7 25.0 — — 96.1 49.5 — — — — 18.7 25.1 — — 93.8 59.1 — — — — 18.5 25.1 — — 100.5 70 — — 6.2 24 — 110.0 25.1 59.3 8.4 25.1 73.2 108.9 23 81 85.8 25.1 12.4 132.3 94 24 59.4 — — — — 17.6 25.1 — — 104.2 74 — — 17.9 23 — 89.2 63.5 25.3 65.1 — — — — 25.2 25.4 — — 103.9 74.0 25.5 11.0 141 155 125.5 85 — 30.1 59.6 — — — 25.8 — — 108.6 25.9 72,3 114.3 128 15.2 128 75 26.4 90.3 120.6 18.4 151 151 94 26.4 75.6 134.4 15.8 138 149 77 --- — — — 19.0 26.4 — — 126.8 78.4 79.0 — — — — 12.3 26.4 — — 125.8 141 73.0 26.5 5.1 85 139 113.1 79.0 — — — 26.7 — — 132.1 — 9.8 66.9 115.7 27.1 21.0 126 72 27.1 - - 121.3 - 4.0 73.9 27.1 79.3 119.5 12.2 88 25 84 56.2 27.4 9.4 103.5 79 25 76 56.3 27.5 9.0 101.3 72 25 73 79 — — 4.6 24 — 127.3 27.6 80.0 67.3 - — - 27.7 - — 110.2 __ 16.8 27.7 63.6 95.3 6.1 124 73 69.4 — — — — 8.8 28.0 — — 113.8 63.2 — — — 28.1 — — 114.5 — 12.3 28.1 — — 114.4 67.2 — — — — 22.2 131 132 123 129 24 24 24 24 26 25 26 25 133 132 —2 91 78 97 88 87 77 27 27 26 27 2— 25 27 125 77 25 25 132 --- - 73 91 - 19.9 11.0 2.8 13.6 14.1 16.7 9.1 9.0 14.6 10.0 8.0 8.6 11.3 11.3 14.2 6.5 18.8 12.9 8.0 10.5 8.1 - 9.9 10.2 8.0 12.3 5.4 - 7.4 9.3 6.6 3.5 15.3 6.1 8.0 6.3 14.0 - 15 6 8 - - - - - 8 6 8 - 12 - 8 - 10 14 12 - 5 - 14 9 6 7 7 — 5 - - - - 7 3 7 - - - - 6 4 5 - 7 - 4 - 8 5 9 - 5 - 9 4 5 4 4 7 - - - - - - - - - - 5 - - - - - - 5 6 - - - - - - - 5 - - - - - 3 3 - - - 3 - 7 3 7 7 - 7 10 8 - - - 5 - 12 - 7 7 7 - - 4 - 7 — 4 4 5 - - 6 - - - - - 5 - - Table 1 Continued. *+Blaney B606 (2X) Cargill 872 (2X) Asgrow RX544 (2X) *+Migro M-2018X (2X) *+Michigan 5802 (2X) Customize CFS WX128 (2X) *+Pride 4488 (2X) *+Amcorn 7300 (2X) Migro HP27 (2X) Trojan TXS102 (2X) Acco UC3002 (2X) *+Great Lakes GL-552 (2X) ADI 197 (X) *+Kaltenberg KX68 (2X) McKenzie 1001 (MSX) Cargill 892 (2X) +ADI 325 (2X) +Michigan 5912 (2X) +Michigan 5922 (2X) *+Cargill 924 (2X) Amcorn 7480 (2X) Migro M-0301 (2X) ADI 315 (2X) 51.1 143 146 138 28 28 28 28 29 90 95 90 25 26 27 86 92 86 28 142.0 85.2 146 124 135 143 143 156 147 151 142 130.6 84.2 140.5 83.6 1.4 12.3 9.8 2.3 11.3 68.7 - - - - 29.3 21.1 0.8 74.2 7.6 74.7 3.1 2 2.2 28.4 28.8 — — 101.5 62.5 — — — — 15.8 - 28.9 — — 114.0 64.8 — — — — 15.1 - 3 5.3 29.1 9 12.9 29.1 29.1 - - 118.7 - 87 — — 1.4 26 — 131.6 1 29.2 9 78 9.9 126 29.8 26 122.0 30.0 — — 103.5 56.6 — — — — 8.5 - 76 - 28.9 22.8 17 30.0 27 - 100.8 79 8.2 12 12.5 59.7 30.1 117.5 75.2 — — — — 8.0 30.2 — — 122.6 - 6.6 30.3 30 — 108.8 77 — — 9.7 5 5.6 55.6 75.4 — — — — 5.8 30.4 — — 131.2 - 4.6 56.7 - - — - 17.7 12.8 - 30.8 - - 103.7 58.8 - 31.1 - — 34.4 23.9 105.7 79.5 — — — 31.1 - — 116.1 - 8.9 13.1 6.1 113.3 31.2 147 75.4 5.3 4 31.2 — - 120.0 81.1 — — — — 1.1 - 2.0 31.3 — — 135.8 82.5 — — — — 11.4 8.4 - 2.3 2 31.8 27 82 1.8 81 32.0 28 14 20.6 12.5 — 5.8 34.4 - - 9.0 106.0 67.5 54.3 103.0 119.2 71.2 136 133 — 134 137 — 78 — 80 85 83 — 28 30 141 89 29 30 — - - - - — 89 Average Range Least significant difference 26.8 24 26 108.5 66.5 21.2 to 34.4 21 to 30 22 to 30 66.9 to 142.0 42.0 to 91.5 131 85 to 156 1.5 1.0 0.7 12.3 7.3 9 81 53 to 98 6 131 94 to 151 6 80 61 to 94 14.2 11.0 9 1.1 to 47.1 0.8 to 42.1 1 to 17 5 — — - *Significantly better than average yield, irrigated, 1979 +Significantly better than average yield, not irrigated, 1979 1 - - 1 7 - 2 7 - 14 4 - 3 - - - - 3 - - 1 7 6 1 to 15 - - 1 - - 1 6 2 - - 3 7 - — - - 5 6 - - - - 3 9 - - - - - - - - - - 3 - - - 2 - - - 1 10 - 7 1 to 12 - 1 5 - 4 1 to 9 - Table 1 Continued. empty table cell Planted Harvested Soil type Previous crop Population Rows Fertilizer Irrigation Soil test: pH Soil test: P K Soil test: 1979 May 19 November 19 Montcalm sandy loam Alfalfa 20,800 30" 213-80-80 6 inches 5.4 493 (very high) 336 (very high) 1978 May 3 November 9 Montcalm sandy loam Corn 20,700 30" 197-60-60 8 inches 6.7 362 (very high) 188 (medium) 1977 April 26 October 28 Montcalm sandy loam Corn 20,500 30" 283-90-90 13 inches 6.7 391 (very high) 174 (medium) Farm Cooperator: Theron Comden, Montcalm Experimental Farm, Lakeview County Extension Director: James Crosby, Stanton MSU is an Affirmative Action/Equal Opportunity Institution