Irish Potato, Control of Colorado Potato Beetle, 1994

Abstract

Abstract The experiments were randomized complete block designs with six replicates each. The four experiments were planted 23 and 24 May at Presque Isle, ME on land that was in clover in 1993. The 3.0 m space between blocks and the 1.8 m space between the four-row plots were bare soil. All rows were planted with an assisted-feed planter 0.9 m apart and 15.0 m long and the healthy whole seed (ca. 75 g) were 30 cm apart. Fertilization and hilling practices were normal for the area. Early and late blight were controlled by eight foliar applications of chlorothalonil. Foliar insecticide applications were made with a Century boom sprayer, three nozzles per row at 6.3 kg/cm2 pressure and 0.94 k liter/ha. Numbers of larvae and adults were counted weekly on 25 whole plants in the middle rows of each plot. When dates of count and application were the same, beetle counts were made prior to application of insecticides. Analyses of variance were calculated following transformations of data using log10(x + 1). Transformed means of the sum of larvae and adult beetles were compared using Fisher’s LSD Test and then applied to the actual means. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was respectively 10.9, 9.6, and 3.3 cm. The average temperature for each of the same 3 months was 17.9, 20.3 and 17.7°C.