Critical Timing for Control of Potato Leafhopper Injury, 1983

Abstract

Abstract ‘Russet Burbank’ potatoes were planted 21 May, at the Rosemount Agric. Exp. St., Dakota Co., Minn. Treatments were applied to the middle two rows of four row plots, 50 ft long, with 40-inch row spacing between plots and 10-inch spacing between plants. The outer 2 rows of the 4-row plots were used for other experiments. Bravo fungicide was applied veekly per label recommendations from 5 Jul. to the end of the season. Insecticides were applied with a CO2 powered sprayer delivering 38 gal water/acre at 30 lb/in2 . Potato leafhopper and other potentially injurious insects were suppressed at various stages of plant development by application of sprays of the insecticide Guthion applied at the rate of 0.5 lb(AI)/acre. Six treatment schedules were employed: (1) (V-I) from the period of vegetative growth (V) until the initiation of tuber formation (I); (2) (V-B) from the period of vegetative growth through the period of mid-tuber bulking (B); (3) from the period of vegetative growth until maturity (M); (4) (I-B) from the period of tuber-initiation until the period of raid-tuber bulking; (5) (I-M) from the period of tuber-initiation until harvest; and (6) (B-M) from the period of mid-tuber bulking until harvest. Spray applications were made on 4 Jul., 19 Jul., 1 Aug., 15 Aug. and 29 Aug. Counts were made from the treated plots by sampling 35 mid-plant leaves per plot for potato leafhopper nymphs.