Efficacy of Three Formulations of Rh-0345 against Japanese Beetle Larvae, Golf Course Rough, 1995

Abstract

Abstract Three formulations of RH0345 (2F, 2.5G, and 5G) were tested for efficacy against Japanese beetle larvae on a golf course fairway in Stockbridge, Mass. The fairway consisted of 40% perennial ryegrass, 30% Kentucky bluegrass, 25% annual bluegrass, and was mowed at ca. 2.0 inches. Pre-treatment samples revealed ca. 20 grubs/ft2, 20% eggs, 45% first instars, 35% second instars. Treatment plots were 8 ft by 8 ft, replicated 5 times, arranged in a RCB. All applications were made between 9:30 and 11:00 AM on 28 Aug 95. Liquid formulations were applied by hand with a watering can, 3 liters per plot. Granular formulations were applied using glass jars with perforated lids. Conditions at the time of application were as follows: air temp. 75° F, light scattered clouds, steady NE wind at 10 to 15 mph; soil type, silty loam; soil pH 6.6; water pH, 7.1; thatch 0.4 inch thick with moderate density. There had been 0.25 inch rain 24 hr before application, but that had been the first measurable rain in 8 wk, so there was considerable drought stress evident. All plots were hand watered with 0.1 inch water immediately after application. No measurable rain fell in the area for 2 wk after application. Product efficacy was evaluated on 5 Oct (38 DAT) by removing 5 cupcutter plugs (4.25 inch diam) from near the center of each plot, dislodging soil with a hand trowel, and counting all grubs to a depth of 3 inches.