Efficacy of Two Formulations of Rh-0345 (A Growth Regulator) and Merit Against European Chafer and Japanese Beetle Larvae, Home Lawn, 1995

Abstract

Abstract Two formulations of RH0345 (2F and 2.5G) and Merit (75 SP and 0.5G) were tested for efficacy against European chafer and Japanese beetle larvae on a home lawn in Waltham, Mass. Grub populations were ca. 60% European chafer, 30% Japanese beetle, and 10% Asiatic garden beetle at the time of evaluation. The lawn consisted of 30% perennial ryegrass, 30% annual bluegrass, 30% crabgrass, and 10% dandelion, and was mowed at ca. 1.5 inches. Treatment plots were 8 ft by 8 ft, replicated 5 times, arranged in a RCB. All applications were made between 10:00 and 11:00 AM on 1 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. 82° F, sunny and moderately humid with light SW wind (5-10 mph); soil type, silty loam; soil pH 6.4; water pH, 8.2. All plots were hand watered with 0.1 inch immediately after application, and an additional 0.2 inch was applied through overhead irrigation within 2 hr after application. No measurable rain fell in the area for 2 wk after application. Product efficacy was evaluated on 11 Sep (41 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.