Reduction of Onion Thrips in Transplanted and Seedling Onions, 1985

Onion seeds were sown on 18 Apr at the University of Nebraska West Central Research and Extension Center Horticulture Plots, North Platte, NE. Transplants were started in the greenhouse from seed on 4 Mar and set in the plots 18 Apr. Onions were irrigated when needed by an overhead sprinkler system. Plots consisted of double rows, 1 seedling and 1 transplant, spaced 18 inches apart and 10 ft in length. The distance between plots was 30 inches. Treatments were applied 18 Jul with a hand-held sprayer at 40 gal/acre at 25 psi. Treatments were arranged in a randomized complete block design with 4 replications per treatment. Evaluations were made by counting the number of adult and nymphal thrips on 2 plants at 5 locations in each replicate. Percent thrips reduction was calculated using the formula presented in the table.