Alfalfa Weevil Larval Control, Missouri, 1977

The test area is part of a 10 acre 3 year old stand of WL-307 alfalfa. The soil is a Shelby loam with a 5-10% slope and 4-8 in. surface soil. Weather conditions, including temperature and rainfall, were monitored at the site by the Department of Commerce, National Oceanic and Atmospheric Administration. Sprays of the compounds under test were applied to 20 x 90 ft plots in a randomized complete block design with untreated checks in four replications. Finished spray treatments at the rate of 20 gallons per acre (in the case of Sumithion at 2.7 gallons per acre) were applied at 40 psi pressure with an IH cub tractor rigged with a 20 ft spray boom and powered by a PTO roller pump. Treatments were applied May 3. Evaluation samples were taken May 10-11, 17-18, and 24-25. Sampling for efficacy was by plucking 25 individual stems of alfalfa from each plot per date and extracting the living larvae by heating in “Berlese” funnels.