Fall Control of Japanese Beetle Grubs with a Granular Insecticide and Entomogenous Nematodes on a Golf Course, Newark, N.Y., 1987

Oftanol 5G and 2 species of entomogenous nematodes were applied to a golf course rough at the Newark Country Club on 25 Aug for control of Japanese beetle grubs. The rough consisted of Kentucky bluegrass (25%), annual bluegrass (60%), and broadleaf weeds (15%). The experimental design was a randomized complete block with 4 replications. Individual plots were 10 × 10 ft. Granular material was applied with a precalibrated Gandy 2.5 spreader. The nematodes, a dessicated and undessicated formulation of Steinernema feltiae Filipjev (strain NC 25) and undessicated formulation of Heterrhabditis sp. (strain Hp 88), were applied at a rate of 5 billion/acre in 11.4 liters of water through a sprinkling can to the center 4 sq ft of each plot. At treatment time (20 Aug) the following environmental conditions existed: air temperature, 72°F; soil temperature, 81°F (1 inch), 76°F (3 inches); soil pH 7.0; water pH 6.8; organic matter, 5.3%; soil moisture, 7.0%; soil texture, coarse sand, 11.8%, medium sand 26.7%, fine sand, 38.5%, very fine sand, 17.2%, silt and clay, 5.8%; thatch was —0.25 inches deep. One-half inch of irrigation was applied after treatment. Posttreatment counts were taken on 2 Oct by cutting a 1- × 10-ft strip (2.25 inches deep) lengthwise through the middle of each plot with a mechanical sod cutter and examining the sod and underlying soil for grubs. A 3-sq-ft sample of sod was examined in each plot, and the surviving grubs were counted. Grub species identifications were made in the field.