Colorado Potato Beetle Control on Potatoes, 1992

‘Red Norland’ potatoes were planted in 25 ft rows on 13 May ’92. Plots consisted of a single treatment row. The distance between rows was 72 inches and the distance between plants within the row was 10 inches. The 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 were applied 4, 9, 16, 23, and 30 Jun; 7, 14 and 21 Jul. Plots receiving AC 303630 were treated 4, 16, 23, and 30 Jun. The plots receiving Trigard were treated with Vydate 2 L at 0.75 lb Al/acre on 3 and 7 Jul to control Colorado Potato beetle adults. Trigard treatments were applied biweekly on 4, 16 and 30 Jun; 7 and 21 Jul. In evaluating the treatments, direct counts of the number of adults, larvae and egg masses/10 stems 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 & Hills 1978). Yields were taken on 29 Jul from 25 feet of row.