Fall Control of Japanese Beetle Larvae in Bluegrass Turf, 1982

The experiments were conducted in the left rough of No. 3 fairway at Blackhawk Golf Course, Westerville, OH. The turf was composed of approximately 90% Kentucky bluegrass and 10% crabgrass. Mowing height was 2.5-3 in. There was no measurable thatch at this site. The predominent soil type was Alexandria-Cardington, characterized as a greyish brown, strongly acid, friable silt loam 8-12 in thick. Environmental conditions at application time were as follows: air temperature, 70 F; relative humidity, 90%; wind from the NW at 0-4 mph; overcast skies; and dry soil. Nine treatments replicated 4 times were applied to 6ft × 8 ft (1.8m × 2.4m) experimental plots arranged in a RCB design. Liquid applications were made using a CO2 pressurized sprayer with 3 8020 nozzles mounted on a 4 ft aluminum boom, operating at 25 psi with a 4 gal/1000 ft spray rate. Granular materials were applied with a 2 ft Gandy drop spreader. All treatments were irrigated with 0.25 in of water immediately after application on Sep 15. Pretreatment counts showed a range of 16-30 grubs/ft. The experimental plots were evaluated at 40 DAT (Oct 25), by randomly sinking four 7.75 in diameter cylinders (ca. 0.33 ft) into the turf to a depth of 8-10 in and counting the number of viable larvae in the plugs of soil.