Prebloom Control of Insect Pests of Alfalfa Seed, 1987

Chemical treatments were applied on 14 May on a 3-yr-old stand of ‘Shenandoah’ seed alfalfa in Touchet, Walla Walla County, Wash. Spray treatments were applied using a C02-powered backpack sprayer calibrated to deliver 27 gal/acre at 30 psi. Four 8003 flat-fan nozzles were arranged at 19-inch spacings on a 4-ft boom. A completely randomized design was used with 0.01 acre plots replicated 4 times. Insect populations were sampled at 7, 14, 21, and 28 days posttreatment with 5 180-degree sweeps made with a standard 15-inchdiam sweep net. Adults of the alfalfa weevil were not reported because there were fewer than 1 adult/sweep in the posttreatment counts; populations remained at low densities throughout the sampling period.