Efficacy of Four Turf Insecticides Against Japanese Beetle Larvae, Golf Course Rough, 1995

Abstract

Abstract Four turf insecticides (Triumph, Merit, Turcam, and Proxol) 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 on 14 Aug revealed ca. 18 grubs/ft2, 30% eggs, 65% first instars, 5% second instars. Treatment plots were 8 ft by 8 ft, replicated 5 times, arranged in a RCB. Triumph, Merit, and Turcam applications were made between 9:30 and 11:00 AM on 14 Aug 95. Proxol was applied on 14 Aug, 30 Aug, or 18 Sep. Liquid formulations were applied by hand with a watering can, 3 liters per plot. Conditions at the time of application were as follows: 14 Aug–air temp. 80° F, light scattered clouds, calm, low humidity; 30 Aug–air temp. 70° F, sunny, light W wind (<5 mph), low humidity; 18 Sep–air temp 75° F, sunny, moderate NW wind (10 mph); soil type, silty loam; soil pH 6.8; water pH, 7.2-7.4; thatch 0.4 inch thick with moderate density. All plots were hand watered with 0.1 inch water immediately after application. Product efficacy was evaluated on 2 Oct 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.