MANAGEMENT OF BIFENTHRIN-RESISTANT SOUTHERN CHINCH BUGS, 2008

Combination field/laboratory trial were conducted to assess the efficacy of several experimental and existing insecticides against a highly bifenthrin-resistant SCB population. SCB in Orange Co., FL, were collected from infested lawns where product failures had occurred using a modified vacuum. SCB were temporarily placed in a laboratory colony. Field plots (3×3 ft) were set up on St. Augustinegrass variety ‘Floratam’ at the University of Florida Plant Science Unit in Citra, FL. Untreated 11⁄2 ft buffers were left between all plots. Turf height was ~3 inches, and thatch thickness was ~1 inch. Treatments were applied to plots on 18 July 2008, in a RCB design with four replications. Check plots remained untreated. Treatments were premeasured in the laboratory and granules were applied to plots with a handheld shaker. Liquid applications were applied using a 2-nozzle, 3-ft boom (19 inch nozzle spacing) connected to a backpack sprayer at 32 psi, with 2 liter bottles and a CO2 tank. Spray volume was using 130 gpa of spray solution. Treatments were applied by walking in one direction, then turning 90 degrees and applying perpendicular to the original direction. About 0.15 inch of posttreatment irrigation was immediately applied. The weather at application: clear sky, dry grass blades (moist soil), wind <2 mph, 53% relative humidity, air temperature 92 ̊F, and average soil temperature 77°F. About 5 inches of precipitation occurred through 13 August, and a total of 14 inches was recorded through 9 October. Four evaluations were conducted. One 6-inch diameter turf core was removed from each plot on 24 July, 13 August, 11 September, and 10 October 2008, placed in plastic pots, and brought to the laboratory. Twenty adult bifenthrin-resistant SCB were caged onto each pot with fine chiffon mesh, and held in the laboratory under room temperature and 13:11 h (L:D). After 4-5 days of exposure, any live SCB recovered during a 2-h long hot water float were collected and preserved. A one-way ANOVA was conducted on the raw data, and if significant (P = 0.05), means were separated using Tukey’s HSD. Percentages of SCB survival based on the controls are presented.