Although feeding on fruit of some crops, such as peach , grape berries are rarely attacked. Feeding is concentrated in the upper part of the vine canopy. Peak adult activity is in July, but may continue into September. Eggs are laid in the soil, hatching in about two weeks. Females make several trips to the soil, laying 1-4 eggs each time.
Young larvae feed on grass roots until cold weather when they descend deeper into the soil.
Apparently Japanese beetle is more abundant on grape in Virginia than in other eastern states. Intensive feeding by Japanese beetle after veraison caused the most severe effects on fruit quality. This loss occurred in less than half the time relative to natural feeding, about 3 weeks compared with 6 weeks, respectively. While mature vines can withstand some foliar feeding, greater care must be take to protect young vines, which may be totally defoliated. This biological control agent can protect grassy areas from large larval populations, but it is ineffective against adults entering the vineyard.