Miticide Efficacy Test, 1983

This experiment was conducted on a furrow irrigated corn field at the Garden City Exp. St. in Finney County, Kans. Eighteen treatments were arranged in a randomized complete block design with four replications. Each plot was 3 m wide (four rows) and 15 m long surrounded by a 3 m-wide border of untreated corn. Chemical treatments were applied on 6 Aug. with a high clearance sprayer using a 3 m boom with three nozzles directed at each row (one nozzle directly over the row and two suspended on 46 cm drop hoses). The sprayer was calibrated to deliver 20 gal of water/acre with 30 lb/in2 of CO2 pressure. About a week before treating the plots, four plants were selected from the center two rows of each plot and flagged. Two of these plants were innoculated with Banks grass mites and two of the plants were innoculated with twospotted spider mites in an effort to augment the natural population of Banks grass mites and establish twospotted mites in the plots. Counts were made by visually searching the leaves on one side of each of these marked plants for adult female mites. Percent twospotted spider mites was established by randomly collecting approximately five mites, using an aspirator from every other leaf of the two plants innoculated with twospotted mites and then mounting 20 adult mites per plot for microscopic examination.