Aster Leafhopper and Aster Yellows Control in Carrot, 1983

Abstract

Abstract Three insecticides were evaluated to determine their effects on the aster leafhopper and its transmission of aster yellows (mycoplasma-like organism) to carrots. The trial was conducted at the Univ. of Minnesota Agric. Exp. Stn., Rosemount, Minn. Each plot had two 20-ft rows (40-in. centers) of ‘Scarlet Nantes’ (aster yellows resistant) and ‘Nantes Coreless’ (aster yellows susceptible) and treatments were arranged in a randomized complete block with four replicates. Both sides of each plot were bordered by two rows of lettuce, Lactuca sativa L., ‘Great Lakes’ which remained unsprayed and served as a source of aster leafhopper and aster yellows. Individual plots were separated from others by 10 ft of bare ground on all sides to minimize interplot movement of ickpack sprayer at 30 lb/in2 (27.0 the aster leafhopper. Treatments were applied using a CO2 powered backpack sprayer at 30 lb/in2 (27.0 gal/acre) except for Sevin XLR which was applied at 15 lb/inz (11.5 gal/acre). Treatments were applied biweekly from 30 June to 4 Aug. and weekly from 4 Aug. through 25 Aug. Fourteen applications in all were made. Sweep samples were taken with a 15-in. diameter sweep net (25 sweeps per plot). Insect counts were taken from all four rows, but not separated with respect to cultivar.