Colorado Potato Beetle Control on Potatoes, 1993

Abstract ‘Kennebec’ potatoes were planted in 20 foot rows on 8 Apr, ’93. Plots consisted of 5 treatment rows. The distance between rows was 64 inches and the distance between plants within the row was 10 inches. Plots were arranged in a randomized complete block design with 4 replications. The soil was a Norfolk “ A ” loamy sand. All spray treatments were mixed in 1.5 gallons of water and applied with a custom built compressed air row crop sprayer. Each row was covered by 6 drop nozzles delivering 50 gal/acre at 28 psi. Treatments of Admire, Novodor and Vydate were applied 21 May; 2, 9, 16 Jun. Plots receiving Trigard 75WP were treated 21 May at .250 lb Al/acre and 2, 14 Jun at .125 lb Al/acre. Plots receiving Trigard, Novodor, and Vydate were treated with Vydate 2L at 0.75 lb Al/acre on 22 Jun to control Colorado potato beetle adults. In evaluating the treatments, direct counts of the number of Colorado potato beetle adults, larvae and egg mass/ 10 plants and the % defoliation were recorded. Defoliation categories were assigned using a pretransformed defoliation rating scale, based on dividing 90° into 13 steps corresponding to arcsin transformation values (Little & Hill 1978). Yields were taken on 28 Jul from 20 feet of row.