Efficacy of Several Turf Insecticides Against European Chafer Larvae, Home Lawn, 1995

Six turf insec-ticides were tested for efficacy against European chafer larvae on a home lawn in Waltham, Mass. Grub populations were ca. 60% eggs, 40% early first instar at the time of application. 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 11:00 AM and 12:30 PM 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. 85° F, sunny and moderately humid with light SW wind (5-10 mph); soil type, silty loam; soil pH 6.6; 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 17 Oct (77 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.