PREVENTIVE CONTROL OF WHITE GRUBS ON A GOLF COURSE ROUGH, 2008

This study evaluated new insecticides for preventive control of white grubs in turf. The test was located on the irrigated rough, south-center side of fairway #8, at Thorn Apple Golf Club, Gallaway, Ohio. Treatments were applied 22 Apr & 1 Jul to plots 8 ft x 8 ft arranged in a RCB design replicated four times. Liquid treatments were applied using a 3 ft wide CO2 pressurized sprayer with TeeJet 8004 nozzles at 20 PSI calibrated to deliver 2.0 gal/1000 ft. Plots received daily irrigation. Field conditions at time of 22 Apr applications were: turf – 85% perennial ryegrass, 10 % tall fescue and 10 % Kentucky bluegrass, mowed at 3.0 inch, thatch-0.25-0.5 inch; soil – clay loam, humid, essentially flat, 70°F at 1 inch, 68°F at 3 inches; weather – air temp 72°F, partly cloudy, 0-3 mph wind from north northwest; pests – generally infested in 2006 & 2007. Field conditions at time of 1 Jul applications were: turf – same as above, 86°F at 1 inch, 82°F at 3 inches; weather – air temp 82°F, sunny, 0-3 mph wind from north northwest; pests – moderate adult JB activity noted. Efficacy data were obtained 3 Oct (165 & 95 DAT, respectively) by counting the number of live white grub larvae in one 12 inch wide by 24 inch sod sample (=2 ft) cut from the exact center of each plot. The sod cutter was set at 1.5-inch depth and the sod was torn apart and underlying soil was raked with metal hand cultivators to expose grubs. ANOVA was performed on untransformed totals per plot and means separated by LSD at α= 0.05. All treatments provided significant control, regardless of application date. Untreated checks had an average of 7.8 white grub larvae per ft, which is considered to be a moderate population. No phytotoxicity was observed after any of the treatments. This research was supported by industry gifts of research funding.