Control of Thrips Tabaci on Cabbage, 1992

Cabbage was transplanted on 16 Jun at the Vegetable Crops Research Farm near Geneva, NY. Plots consisted of two 10 ft rows on 36 inch centers with 18 inch plant spacing. Treatments were replicated 3 times in a randomized complete block design. A backpack sprayer with a one-row boom, having 3 nozzles per row with HC 12 hollow cone tips, and delivering 38 gal/acre at 40 psi and 2 mph, was used to apply applications of each treatment. Javelin at 1.0 lb/acre was added to M-pede, Cygon and the check treatments to control Lepidoptera and insure readable plants at harvest. Bond sticker-spreader was applied at .01% v/v with all treatments. Treatments were applied on 27 Jul, 6, 14, 27 Aug, 4, 11, 18 Sep and 2 Oct. Harvest evaluations for thrips were made on 8 Oct. Evaluations for thrips damage were made by randomly selecting 2 mature heads per plot, cutting them in half along the core, and peeling back 10 layers. Each layer was assessed for the presence of thrips injury. The overall damage rating (intensity of injury plus the number of layers injured) was also made on a scale of 0 (no damage) to 4 (each of the 10 leaves severely injured). Data were analyzed by a two-way ANOVA. For analysis of damage ratings we used the average damage rating per replicate, transformed this to a rank, and analyzed ranks. For layers injured, we used the average number of layers per two plants in a replicate and then analyzed these averages.