Early Season Control of Bluegrass Billbugs on a Kentucky Bluegrass Lawn in Saunders Co., Nebras-Ka, 1995

Abstract Insecticides were evaluated for control of bluegrass billbug larvae on a Kentucky bluegrass lawn at the University of Nebraska Agricultural Research and Development Center near Mead, Nebraska. The turf (98% Kentucky bluegrass, 2% tall fescue) was maintained at a mowing height of 3 inches. Thatch accumulation (finger compressed) in the plot area was 0.75 to 1.0 inches. Field conditions at the study site were: soil type, silty clay loam; soil organic matter, 3-5%; soil pH, 6.7; water pH, 7.0. Environmental conditions at the time of application were as follows: soil moisture 17%; air temperature 67°F; soil temperature 63°F; relative humidity 48%; wind direction and velocity 107° at 7 mph. Plots were 6 X 6 ft and the experimental design was a RCB with 4 replications. Treatments were applied 25 May 1995. Granular insecticides were applied with a pre-calibrated 24H12 Gandy spreader. Liquid insecticides were applied using a CO2 sprayer with an LF-4 nozzle at 30 psi and delivering 2 gal finished spray/1000 ft2. Following applications, plots were irrigated with 0.5 inches of water. A total of 3.13 inches of rain fell during the post treatment period. Treatments were evaluated 48 DAT (13 Jul) by removing from each plot three, 8-inch diam turf-soil cores (1.05 ft2 total area) to a depth of 3 inches and counting the number of surviving billbug larvae and pupae. Approximately 25% of billbug oviposition had been completed at the time of application.