Ontrol of Japanese Beetle and Southern Masked Chafer Grubs, 1992

Abstract

Abstract CThis study was conducted in a 2-yr old stand of tall fescue at Elkhorn Springs Sod Farm, near Frankfort, KY. The turf was on a Maury silt loam soil (fine-silty, mixed, mesic Typic Paleudalf). Soil texture was 23% clay, 74% silt, and 3% sand, with 8.8% organic matter and pH = 6.4 Thatch accumulation was negligible. Plots (7 x 10 ft) were established in a RCB with five replications, with 2 ft untreated boundaries between plots. The turf was mown to 3" height before treatment, with the clippings raked and removed. Treatments were applied on 18 Aug. Liquid formulations were applied with a high pressure CO2 sprayer that delivered 2 gal of spray per 1000 ft2. Granular treatments were diluted with dry sand and applied to the plots by gloved hand. Nematode treatments were applied last, after which all plots were irrigated with about 0.5 inch of water, beginning 5-10 min after the final treatment was applied. Conditions at the time of application were sunny, 78°F, 57% relative humidity, and 5 mph winds. The soil was moist due to the 0.45 of rain that had fallen in the previous 4 d. The grub population at the time of treatment consisted of a mixture of 2nd and 3rd instars of each species. Treatment effectiveness was assessed 29-30 DAT by cutting a strip (25 X 18 inches, 2.5 inches deep) from the center of each plot with a motorized sod cutter. The sod strips were broken apart and examined for living grubs in the field. Data were analyzed by ANOVA followed by Fisher's protected LSD test to separate treatment means.