Summer 93 v4#2 single page

4 tudies during 1992-93 in our long-term research and development program to introduce biologically based control agents for scarab grub control in turfgrass has focused on evaluating a number of entomopathogenic agents (entomopathic nematodes and fungi) against Japanese beetle grubs. Fourteen Metarhizium anisopliae isolates, a fungal pathogen of soil insects, were tested against Japanese beetle grubs. Two isolates, MADA and 1020 are currently being considered for commercialization. The other twelve isolates were chosen because they were isolated from scarab grubs from around the world. MADA and 1020 performed well at both treatment rates, but there were clearly isolates that performed consistently better over the study. There was considerable differences in how well several fungal isolates performed under a variety of environmental conditions that are commonly found in Metropolitan area golf courses. Studies were also initiated to determine if combinations of fungal pathogens and traditional insecticides might increase grub mortality and reduce the lag time common for many insecticides in soil. These preliminary studies suggest that this may occur. Further work in this area will be undertaken in 1993. The addition of fungal pathogens to composts for top dressings was also studied in 1992. Although this work is preliminary we have encouraging results and will continue this study during the rest of the project. A second 1992 research focus was in evaluating entomogenous nematodes under a variety of environmental conditions to determine those conditions that promoted maximal grub mortality. These studies suggest that under specific environmental conditions, commercially available entomopathic nematodes may outperform standard turfgrass insecticides for controlling grubs. Research in 1993 will focus on field studies to verify these laboratory and greenhouse results. We have also studied several nematodes that have been collected by Cornell University entomologists that appear to compare favorably to commercially produced nematodes against Japanese beetle grubs. Large plot studies are planned for 1993.