Adult Japanese beetles will feed on more than 275 different plants. Damage varies from slight to severe. Wild blackberry, grape, elderberry, smartweed, and roses often attract masses of adults. These plants often abound in or near sites optimal for oviposition and larval survival. The beetles often congregate and feed on flowers, foliage, and fruit of plants and trees exposed to bright sunlight.
Beetles feeding on leaves usually chew out the tissue between the veins, leaving a lacey skeleton.
A badly attacked tree or shrub may lose most of its leaves in a short time. The beetles often mass and feed on ripening fruits. They seldom touch unripened fruit. They seriously injure corn by eating the silk, preventing kernel formation. Adult Japanese beetles appear on the foliage and flowers of favored host plants about July 1 in Vermont.