Irish Potato, Control of Colorado Potato Beetle with Exp60434A (Fipronil), 1991

Abstract

Abstract The experiment was a randomized complete block design with six replicates and was planted on 16 May at Presque Isle, ME on land that was in clover in 1990. 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 three foliar applications of Dithane M-45 (80WP) (1.12 kg/ha on 18 and 26 Jul; 2 Aug) and Bravo 720 (840 g/ha on 9 and 23 Aug). Foliar insecticide applications were made with a Century boom sprayer, three nozzles per row at 6.3 kg/cm2 pressure and 0.94 kliter/ha. Numbers of 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, beetle counts were made prior to application of insecticides. Analyses of variance were calculated following transformations of data using logH1(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 3.7, 1.9, and 21.7 cm. The average temperature for each of the same 3 months was 17.1, 19.0 and 19.3 °C.