Influence of Application Timing of Wrc928-12356 on Annual White Grub Control, 1992

This study was conducted in Lincoln, NE on a Kentucky bluegrass (50%) and perennial rye (50%) golf course rough. The turf was maintained at a mowing height of 3.8 cm and thatch accumulation (finger compressed) in the plot area was 0.64 to 1.3 cm. Field conditions at the time of application were; soil type, silty clay loam; soil organic matter, 3-5%; soil pH, 6.0 to 7.0; water pH, 7.0; soil moisture, near field capacity. Plots were 2.44 X 2.44 m and the experimental design was a RCB with 4 replications. Liquid formulations of WRC928-12356 were applied 10, 17, 24 and 31 Aug. Some plots treated 10 and 17 Aug received a second application on 24 Aug and 31 Aug, respectively. Triumph 4 E was applied 17 Aug at the time of estimated 99% SMC egg hatch (based on light trap monitoring of the SMC beetle flight). Subsequent light trap collections and projections of oviposition and egg development, indicated 99% egg hated occurred approximately 16 Aug at the study site. Insecticides were applied with a using a C02 sprayer using a LF-4 nozzle at 165.5 KPa and 18.9 liter/93 m2. Product efficacy was evaluated 22 Sep (22 days following the last application) by removing six, 20.3 cm diam turf-soil cores (0.19 m2 total area) to a depth of 7.6 cm, from a 1.22 x 1.22 m section in the center of each plot. Numbers of surviving grubs were recorded.