Control of White Grubs with a Bt Biotoxin, 1996

Several formulations of the ‘Buibui’ strain of Bacillus thuringiensis japonensis were evaluated with chemical insecticide standards for control of Japanese beetle grubs at the Purdue University Nursery Grounds, West Lafayette. IN. Treatment plots were 10 X 10 ft, arranged in a RCB design, replicated 5 times. Treatments were applied on 16 Aug. Granular formulations were applied with a homemade salt shaker. Dispersable formulations were mixed in 2-Liter plastic bottles and dispensed through a hole poked in the cap of the bottle. Plots were moist prior to application and received 1 cm of sprinkler irrigation immediately after treatment. Conditions at the time of treatment were: air temp., 21°C and wind speed 1—5 mph. Efficacy was evaluated on 28 Sep by extracting cores from five random locations within each plot using a golf-hole cup cutter (0.90 square ft.) Soil to a depth of 4 inches, thatch and turfgrass from each core was examined for the presence of live grubs. The average number of live grubs from the five subsamples within each plot was used as the dependent variable in the statistical analysis of the data. There were two untreated plots in each replicate.