Experimental Neem-Based Insecticide 43178F/17 for Control of Japanese Beetle Grubs, 1991

Abstract

Abstract This study was conducted in a Kentucky bluegrass plot at the University of Kentucky Spindletop Research Farm, Fayette Co., KY. The established turf was on a Maury silt loam soil (fine-silty, mixed, mesic Typic Paleudalf), with pH = 6.2. Thatch accumulation was <0.25 inch. Throughout Jun and most of Jul there was a very heavy flight of adult JB in the vicinity of the test site. Preliminary sampling of the border areas surrounding the plot suggested an endemic JB grub population of about 6-8/square ft at the time of treatment. Plots (7 × 7 ft) were established in a randomized complete block design with 5 replications of four treatments, corresponding to three rates of 43178F/17 (20, 50, or 100 g Al/acre) plus an untreated control. The plots were treated on 30 Jul, using a high pressure COa sprayer that delivered 2 gal of spray/1000 ft2. Temperature at the time of application was 78°C, with 72% relative humidity and 5 mph winds. All plots were irrigated with about 0.75 inch of water immediately after treatments were applied. The grub population at the time of treatment consisted of mostly second instars, with a small no. of first and third instars also present. Treatment effectiveness was assessed 30 DAT by removing 12 cores (8 inch diam, 7 inch deep) from each plot with a golf-type turf mender. These were broken apart in the field, and all living or apparently moribund grubs present) were collected into separate containers for each plot. Grubs were returned to the laboratory where they were sorted to species, counted, and weighed on la Mettler electronic microbalance.