Transgenic Potato Plants, Control of Colorado Potato Beetle, 1991

The experiment was a randomized complete block design with six replicates, planted 21 May at Presque Isle, ME on land that was in clover in 1990. Each replicate consisted of a single row of ten plants 30 cm apart and separated by two blank rows plus two rows of 'Russet Burbank' potatoes. A 3.0 m space of bare soil separated blocks and surrounded the experiment. Fertilization and hilling practices were normal for the area. Early and late blight were controlled with three foliar applications of Dithane Mi 45 (80 WP) (1.12 kg/ha on 18, 26 Jul, and 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 kl/ha. Numbers of larvae and adults were counted weekly on 6 whole plants in each plot. When dates of counts 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 DMR.T. The Asana treatment was applied on 17 Jul and 2 Aug at the label rate. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was 3.7, 1.9, and 21.7 cm, respectively. The average temperature for these three months was 17.1, 19.0, and 19.3 deg. C.