Suppression of Black Cutworm Larvae with Spinosad, Bifenthrin, Chlorpyrifos, and Experimental Formulations on Creeping Bentgrass, 1997
Abstract Treatment plots were 6 x 8 ft, arranged in a RCB design and replicated 4 times. White PVC cylinders (8-inch diam x 6 inch length) were placed in each replicate and secured in place. One cylinder was placed in each replicate per evaluation period (28 Jul and 30 Jul). Fifteen 0.125-inch black cutworm larvae were placed in each cylinder on 22 Jul. Bird netting was placed over the experimental area from 22 Jul through 28 Jul to prevent bird predation. Liquid formulations were applied by using a CO2 compressed-air sprayer with 4 8002VS Tee-Jet nozzles mounted on a 6-ft boom, operating at 28 psi, and applied in 363 ml of water/48 ft2 or delivering 2.0 gal/1,000 ft2. At treatment time (25 Jul), the following soil and environmental conditions existed: air temperature, 63° F; soil temperature at 1 inch depth, 62° F; soil temperature at 2-inch depth, 60° F; RH, 96%; amount of thatch, 0.125 inch; soil textural class, sandy loam; soil particle size analysis: 61.3% sand, 27.7% silt, 11.0% clay; soil percent water weight (percent by weight), 24.2%; organic matter, 5.2%; water pH, 7.0; soil pH, 6.8; time of application, early morning; and overcast skies. A total of 2.8 inches of rainfall or irrigation was recorded from 22 Jul through 25 Jul; a total of 0.3 inch rainfall or irrigation was recorded from 25 Jul through 26 Jul; and a total of 1.0 inch rainfall or irrigation was recorded from 27 Jul through 30 Jul. Efficacy data were recorded on 28 Jul and 30 Jul by counting the number of black cutworm larvae flushed to the surface within each PVC cylinder by using a soap irritant drench.