Abstract/Contents: | "This trial was conducted on a bentgrass green at Rochester Country Club, Rochester, NH. The same rate of Mach-2 was applied at timed intervals (23 Apr, 7 May, 20 May, and 4 Jun) to determine efficacy of the product on early to late stages of ABW development. The first application date (23 Apr) was timed to the beginning adult emergence; the last application (4 Jun) was timed to late instar larvae. A comparison of a single full rate versus a split application of Talstar at half rate was also conducted. The full and first half rate treatments were applied on 23 Apr; the second half-rate was applied on 7 May. All treatments were applied to 49 ft₂ plots, replicated four times in a RCB design. Treatments were applied with a 7-ft boom, on a 2-wheel bicycle-type sprayer, using four 8005 fan-type nozzles, fitted with 50-mesh screens, and delivered with CO² at 40 psi. The volume of water and pesticide mix per plot was 2 gal/1000ft². None of the treatments were watered in; however, the greens were irrigated daily. The soil texture was loamy sand, consisting of the following; sand, 85%; silt, 10%; clay, 5%; organic matter, 4.2%; moisture, 16,4%; pH, 5.6. Weather and soil conditions on all application dates were as follows: (23 Apr) sky, overcast; wind, calm; air temp, 52°F; soil surface temp, 53.6°F, at 1-inch depth, 52.7°F; (7 May) sky, light mist; wind, calm; air temp, 56.1°F; soil surface temp, 56.3°F; at 1-inch depth, 57.2°F; (20 May) sky, overcast; wind, calm, air temp, 68.5°F; soil surface temp, 69.6°F; at 1-inch depth, 69.2°F; (4 Jun) sky, sunny; wind, moderate breeze; air temp, 63.2°F, soil surface temp, 62.2°F . On 9 Jun, a 4-inch cup cutter was used to pull four 3-inch deep plugs from each plot; each plug was opened to expose and count live larvae and pupae. All chemical treatments were significantly different from the check. However, Mach-2 gave poor to fair control regardless of timing. The trend suggested Mach-2 worked best when applied against young larvae. Both the single full, and split half rate applications of Talstar gave good control. There was no advantage to splitting the Talstar applications. No phytotoxicity was observed. The check and Mach-2 plots were damaged by larval feeding." |