Summer Control of Japanese Beetle Grubs on a Golf Course Fairway in Mifflin Co., Pa, 1986

Fifteen insecticide treatments were applied on 18 Aug for control of Japanese beetle grubs. The fairway consisted of annual bluegrass (40%), Kentucky bluegrass (30%), and perennial ryegrass (30%). Treatment plots were 6 x 9 ft, arranged in a RCB design and replicated 3 times. Liquid formulations were applied by using a C02 sprayer with four 8004VS Tee Jet nozzles mounted on a 6-ft boom, operating at 28 psi with a 5 gal/1,000 ft2 spray rate. Granular formulations were applied with a hand held shaker, and mixed with a fine grade of calcined clay top dressing (Terragreen) to facilitate product distribution. At treatment tim the following soil and environmental conditions existed; air temp, 76°F; soil temp, 80°F; % RH, 78; amount of thatch, 0.25-0.5 inches; soil type, loam; % soil moisture, 13.4; soil pH, 5.7; % organic matter, 2.7; water pH, slightly acidic; amount of rain occurring over posttreatment period, 2.65 inches. Immediately after treatment the experimental area was irrigated with 0.5 inches of water. Posttreatment counts were made 35 DAT (23 Sep). Three ft2 sod samples were randomly taken from each replicate and the total number of Japanese beetle grubs per ft2 was recorded. An average of 22.5 Japanese beetle grubs per ft2 was recorded 18 Aug.