Control of Colorado Potato Beetle on Potato, 1995

Abstract

Abstract Standard and NewLeafR (NatureMarkR, producing Bacillus thurin-giensis subsp. tenebrionis 8-endotoxin) potatoes were planted 11 May at the University of Minnesota Agricultural Experiment Station, Rosemount, MN. Plots were each 8 rows by 50 ft and separated from other plots by 10 ft of soybean border. Treatments were arranged in a RCB design with 4 replications. Admire 2F was applied in-furrow at planting prior to closing the seed bed by using a CO2 pressurized sprayer, delivering 60 gal/acre at 35 psi. All other spray applications were made by using a tractor-mounted boom sprayer with 3 nozzles per row, delivering 60 gal/acre at 90 psi. Threshold of 30% egg hatch was used to initiate Novodor applications. Novodor as required treatments were applied at presence of <80 small larvae (1st and 2nd instars). Orthene 75S was used to control green peach aphid on selected treatments. Late blight control was achieved by 5 spray applications of Bravo 500 (1 pt/acre) on 28 Jun; 7, 13 and 29 July; and 8 Aug, and 3 applications of Ridomil/Bravo 81WP (1 lb/acre) on 20 Jul; 2 and 18 Aug. Malathion 57EC (0.5 pt/acre) was used to control potato leafhoppers on 12, 29 July; 2 and 16 Aug. CPB egg masses, small larvae, large larvae (3rd and 4th instars) and adults were counted on 10 whole plants per plot on 23, 27 June; 3, 10, 18 and 26 July; 2, 8, 14, 23 and 29 Aug. NewLeafR potatoes provided season long commercially acceptable control of all CPB life stages. Fewer egg masses were laid on NewLeafR potatoes than other treatments. No small or large-larvae were found indicating that none of the neonates survived. Significantly lower numbers of CPB adults were observed on NewLeafR potatoes.