Do turfgrass species influence oviposition site preference in Japanese beetles (Popillia japonica Newman)?

The Japanese beetle (Popillia japonica Newman) is a relatively new pest in Arkansas where environmental conditions, turf varieties, and soil types differ from the Northeast and Midwest US where most Japanese beetle research has been carried out. Two oviposition choice experiments were conducted to determine whether turfgrasses commonly found in Northwest Arkansas influence Japanese beetle oviposition site preference. We quantified preference by counting the number of eggs collected from the turf after seven days of allowing a mated female to oviposit in a bioassay arena with different turfgrass species. We conducted a four-choice oviposition site experiment with one cool-season grass, Tall Fescue (Festuca arundinacea), hypothesized to have significantly more eggs, and three warm-season grasses: Bermuda (Cynodon dactylon), Tifway (Cynodon dactylon x Cynodon transvaalensis), and Zoysia japonica. A three-choice oviposition site experiment was also conducted to identify differences among solely the three warm-season grasses, hypothesizing that Zoysia would have significantly fewer eggs. Preliminary results show significantly greater egg numbers in Tall Fescue and Zoysia than Tifway in the four-choice experiment; and significantly greater egg numbers in Zoysia than both Bermuda and Tifway in the three-choice experiment. These results may indicate a turfgrass species that is significantly less preferable than other turfgrass species to Japanese beetles searching for an oviposition site. This information may lead to recommendations about what turfgrass species to plant to homeowners or golf course managers concerned about Japanese beetle larval damage.