Aster Leafhopper and Aster Yellows Control in Carrot, 1984

Three insecticides were evaluated to determine their effects on the aster leafhopper and its transmission to aster yellows (mycoplasma-like organism) to carrots. The trial was conducted at the University of Minnesota Agricultural Experiment Station, Rosemount, MN. Each plot had eight 20-ft rows (12-inch centers), and treatments were arranged in a randomized complete block with 4 replicates. Both sides of each plot were bordered by 2 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 the aster leafhopper. Treatments were applied using a CO2 powered backpack sprayer at 40 psi (57.5 gal/acre). Application dates were 18, 24, 31 Jul and 16 Aug. Sweep samples were taken with a 15-inch diam sweep net taking 25 sweeps per plot.