| Abstract/Contents: | "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. All of the treatments except the 30 Aug Proxol application reduced grub populations significantly relative to the untreated control. While two of the three Proxol applications reduced grub populations significantly, none of the Proxol treatments provided agronomically acceptable levels of control (ca. 75%). Proxol often is used to treat grub-infested areas after a population has developed. These data suggest that the performance of the material in such circumstances can be inconsistent. Possible explanations (which may or may not have been present in this field trial) include: hydrophobic thatch, very dry soil conditions, inadequate post-application irrigation, high pH of water used in application, high pH of irrigation water. There was no significant difference between formulations or rates of Triumph." |
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