Evaluation of Kaolin Clay as an Alternative Management Tactic for Japanese Beetle Feeding Damage in Grape Vineyards

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is an exotic, introduced Scarab that has become one of the most widespread and destructive insect pest of turf, landscapes and nursery crops in the eastern United States. It also damages various fruit, garden and field crops. Evaluation of certain conventional and non-conventional control agents in a Wisconsin vineyard revealed that bifenthrin, a fourth generation synthetic pyrethroid, provided the greatest Japanese beetle adult control in choice and no-choice feeding bioassays. Bacillus thuringiensis gallariae (Btg) was also effective in both bioassays. However, Btg residual activity was relatively limited; its performance decreased five days after treatment. Kaolin clay provided effective Japanese beetle adult management via consistent adult feeding damage mitigation in both study years. Field tests showed that various application Kaolin clay rates were effective in minimizing feeding damage by Japanese beetle adults, and no adverse effects were observed on several important fruit quality characteristics such as sugar content (Brix), acidity, number of fruit produced per plant and fruit weight. Kaolin clay is an alternative, non-insecticide management tactic that can be employed by grape growers to minimize feeding damage by Japanese beetle adults and reduce the amount of conventional insecticide input needed to maintain grape quality.