Efficacy of Halofenozide and Imidacloprid Treatments, Applied One Month After Post-Oviposition, to Suppress White Grubs, 1997

Abstract

Abstract The turfgrass, located in University Park, PA, consisted primarily of perennial ryegrass (100%). Treatment plots were 8 x 6 ft, arranged in a RCB design and replicated 3 times. Liquid formulations were applied by using a CO2 sprayer with 4 8002VS TeeJet nozzles mounted on a 6-ft boom, operating at 28 psi, and applied in 727 ml of water/48 ft2 or delivering 4 gal/1000 ft2. Granular formulations were applied with a hand-held shaker and mixed with fine top-dressing sand to facilitate product distribution. Three white PVC cylinders (8-inch diam X 6-inch height) were placed in each replicate and secured in place. Twenty-five JB adults were placed within each chamber and maintained inside by covering individual cylinders with white shade cloth. The latter procedure allowed for oviposition by adult females. PVC cylinders were removed following death of adult beetles. At treatment time (8 Aug) the following soil and environmental conditions existed: air temperature, 68° F; soil temperature at 1-inch depth, 64° F; soil temperature at 2 inch 63° F; RH, 72%; amount of thatch, 0.0625-0.125 inch; soil textural class silty clay loam; soil particle size analysis: 16.4% sand, 55.0% silt, 28.6% clay; organic matter, 6.7%; soil percent water content (percent by weight), 22.3; water pH, 7.0; soil pH, 6.9; treatments were applied in mid-morning; and clear skies. The experimental area was irrigated with 0.1 inch of water after treatments had dried. The area received extensive pre-irrigation watering because of the extremely dry weather conditions with 4.5 inches applied from Jul 2 through Jul 17. Additional irrigation was applied on an as needed basis. Posttreatment counts were completed on 25 Sep. Three ft2 sod samples were randomly taken from each replicate, and the total number of JB grubs/ft2 was recorded.