Control of Green June Beetle Grubs During Egg Hatch Resolves Problem of Grubs Dying on Turf Surface, 1993

Abstract

Abstract This study was conducted in a mature, low-maintenance stand of Kentucky bluegrass in Lexington, KY. The turf was on a Maury silt loam soil (fine-silty, mixed, mesic Typic Paleudalf)- Thatch accumulation was negligible. Plots (10 × 10 ft) were established in a RCB with five replications. There were 2 ft untreated boundaries between plots. The turf was mown weekly to 3 inch height, with the clippings left on the plot surface. Treatments were applied 28 Jul, about 2 wk after peak adult flight activity. Conditions at the time of treatment were sunny, 92°F, with 5-10 mph winds. Granular treatments were diluted with dry sand and applied to the plots by gloved hand. The wettable powder formulation was mixed with water and applied with a Solo backback sprayer using 1 gal of spray per plot. All treatments were immediately irrigated with 0.25 inch of water, using a water truck and hose with a shower-type nozzle. The grub population at the time of treatment consisted of eggs and first instars. Effectiveness of treatments was assessed 61-62 DAT using an insecticide flush method. Triumph 4E (isazophos) was applied at the labeled rate (2 lb (AI)/acre) on 27 Sep, using a Solo backback sprayer that delivered 0.5 gal spray/plot. The flush spray was immediately syringed with 0.25 inch of water as before. Grub populations were assessed at dawn of the following 2 d. A frame (3.3 × 3.3 ft) made from PVC pipe was placed in the center of each plot, and dead green June beetle grubs within the sample area were counted and removed. Counts for the two samples were pooled and analyzed by ANOVA followed by Fisher’s protected LSD to separate treatment means.