Control of Colorado Potato Beetle, 1992

Abstract

Abstract Potatoes were planted 14 May at the Research Farm of the Red River Valley Potato Growers Association, Grand Forks, ND. Plots were 4 rows wide, 18.9 m (62 ft) long, with 96 cm (38 in) spacing between rows and 30 m (12 in) between plants. Plots were arranged in 6 tiers of 34 plots each. Plots were separated laterally by two in planted rows (1.9 m) and tiers were separated by 7.6 m. Borders of plots were maintained weed-free by cultivation. The planting was divided into three experiments each consisting of a completely randomized plot design with 4 replications. Experiment 1 was to evaluate various rates and formulations of Bacillus thuringiensis (B.t) insecticides. Experiment 2 was to evaluate several synthetic organic insecticides and Cryolite. Experiment 3 was to evaluate two neem-based insecticides (ATI-720 and Margosan-O) alone or in combination with other insecticides. Plots were scouted daily for Colorado potato beetle egg masses beginning 11 Jun. When egg masses were found these were flagged and checked daily for hatch. Hatch of flagged eggs reached 25% on 22 Jun. Sprays were applied in all three experiments on 24 Jun, 7 Jul, and 15 Jul. Insecticidal sprays were applied using a tractor-mounted boom sprayer, with a single Teejet nozzle over each row. Sprays were applied in 150 liters of water/ha (40 gal/acre) at 275 kPa (40 psi).