Fall Control of Japanese Beetle Grubs with Granular Insecticides and Entomogenous Nematodes on a Golf Course, 1987

Abstract

Abstract Four insecticides and a species of entomogenous nematode were applied to a fairway at Sleepy Hollow Country Club, Sleepy Hollow, N.Y., on 20 Aug for control of Japanese beetle grubs. The fairway consisted of Kentucky bluegrass (40%), annual bluegrass (40%), bentgrass (15%), and broadleaf weeds (<5%). The experimental design was a randomized complete block with 4 replications. Individual plots were 10 × 10 ft. Granular materials were applied with a precalibrated Gandy 2.5 spreader. The nematodes, a dessicated formulation of Steinernema feltiae Filipjev (strain NC 25), 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, 84°F; soil temperature, 74°F (1 inch), 72°F (3 inch); soil pH 5.7; water pH 9.89; organic matter, 10.2%; soil moisture, 27.0%; soil texture, coarse sand, 8.1%, medium sand, 41.6%, fine sand, 27.6%, very fine sand, 14.3%, and silt and clay, 7.8%; thatch was 0.25-0.5 inches deep. One-half inch of irrigation was applied after treatment. Posttreatment counts were taken on 22 Sep by cutting a 1- by 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. At this time Japanese beetle grubs and European chafer grubs were predominantly third instars.