Control of Colorado Potato Beetle, 1988:

Abstract

Abstract The experiments were randomized complete block designs with 6 replicates. Planting was done on 13 May for experiment CPB-A, 16 May for experiments CPB-B and CPB-C, and 19 May for experiment CPB-D at Presque Isle, Maine, on land that was in clover in 1987. The 3.0-m space between blocks was bare soil, and the 4-row replicates were separated by 2 rows of untreated potatoes. All rows were planted with an assisted-feed planter 0.9 m apart and 15.0 m long and the healthy seed pieces (75 g) were 30 cm apart. Fertilization and hilling practices were normal for the area. Late blight was controlled by foliar applications of Dithane FZ (2338 ml/ha the weeks of 11, 18, and 25 Jul; 2806 ml/ha the weeks of 1, 8, and 15 Aug). Foliar insecticide applications were made with a Century boom sprayer, 3 nozzles/row at 6.3 kg/cm2 pressure and 0.94 kl/ha. CPB larvae and adults were counted on 25 whole plants in the middle rows of each plot. When dates of count and application were the same, insect counts were made prior to application of insecticides. Analyses of variance were calculated following transformations of data using log10(x + 1). Means of the sum of larvae and adult beetles were compared using DMRT and then reconverted. The soil was classified as Caribou loam, pH 5.2. Total monthly rainfall for June, July, and August was 3.7, 8.3, and 13.7 cm, respectively. The average temperature for each of the same 3 months was 15.7, 20.4 and 18.9°C.