Efficacy of Various Insecticides for Control of White Grubs, 1995

This test was conducted in turf-type tall fescue at the University of Kentucky Spindletop Farm, near Lexington. The turf was on a Maury silt loam soil (pH = 6.4) with negligible thatch. Plots (4X6 ft; 2 ft untreated borders) were arranged in a RCB, with 4 replications. The turf was treated on 27 Jul, during flight of JB. The soil population consisted mostly of eggs, with some 1st instars. Granular formulations were preweighed, mixed with dry sand, and applied by gloved hand. Liquid applications were applied at 50 gal/acre using a low volume, CO2 sprayer equipped with 4 Spraying System 8004 Tee Jet nozzles that delivered 2109 g pressure per cm2. Each plot was syringed with about 1/8 inch of water within 5 min after application, and the whole site received 3/4 inch irrigation as soon as the last treatment was applied. Conditions during application were 88°F with winds < 10 mph. There was 0.23 inch of rainfall on 26 Jul, the day before the test. There was no additional rain until 5 Aug, when 1.78 inch fell. The curative application of Dylox 6.2G was made on 17 Aug, with 3/4 inch of irrigation immediately after treatment. All plots were sampled on 16 Sep. A motorized sod cutter was used to cut a 3 X 1.5 ft strip, about 3 inches deep, from the center of each plot. The sod was rolled back, broken apart, and examined for grubs, which were counted and identified.