Individual beetles live about 30 to 45 days. Activity is concentrated over a four to six week period, beginning in July, after which the beetles gradually die. Japanese beetles can feed on about 300 species of plants ranging from roses to poison ivy. Odor seems to be a very important factor in the selection of a suitable food plant. They usually feed in groups, starting at the top of a plant and working downward, and prefer plants exposed to direct sunlight.
Adults feed on the upper surface of foliage, chewing out tissue between the veins.
This gives the leaf a characteristic skeletonized appearance . They tend to do little feeding on thick, tough leaves. The spread of the Japanese beetle infestation is primarily the result of flight by the adults. They can fly as far as 5 miles but 1 to 2 miles is more likely. Usually, they make only short flights as they move about to feed.