Control of Banks Grass Mite in Sweet Corn, 1996

Abstract

Abstract Insecticides were applied with a hand held CO2 sprayer calibrated to deliver 1 18 gpa spray material at 25 psi through four LF4 nozzles at 18 inch spacing mounted on a 4.5 foot boom. Treatments were applied on 3 Jul 1996, when the first silks were appearing on sweet corn that was approximately five feet in height. Plots were 7.5 feet by 30 feet, arranged in a RCB design replicated four times. Only the middle row of the three row plots was used for evaluation purposes. Mites were sampled prior to spraying, and again on 10 Jul (7 DAT). Sampling involved collecting five random ear leaves per plot, brushing the leaves with a Leedon Engineering Mite Brushing Machine, and counting a subsample of the extracted mites. Damage evaluations were made on 29 Jul, when sweet corn was harvest ready, by rating each plot on a 0-5 damage scale: 0 = no damage, 1 = 1-20% ears damaged by mites, 2 = 21-40% damaged ears, 3 = 41-60% damaged ears, 4 = 61-80% damaged ears and 5 = 81-100% damaged ears. Data were (X + 0.5)½ transformed before analysis of variance. Actual means are presented.