Larvae move downward in the soil as soil temperatures decline and form an earthen cell in which they overwinter. In the spring, larvae return to the soil surface, feed for a short time, and pupate in May. After two weeks in the pupal stage, the adults emerge and crawl to the soil surface to begin their cycle again. There is but one generation per year. Damage Symptoms Despite its common name, the rose chafer attacks the flowers, buds, foliage, and fruit of numerous plants including grape, rose, strawberry, peach, cherry, apple, raspberry, blackberry, clover, hollyhock, corn, bean, beet, pepper, cabbage, peony, and many more plants, trees, and shrubs.
Adults emerge about the time of grape bloom and often cause extensive damage to foliage.
Blossom buds are often completely destroyed, resulting in little or no grape production. Feeding activity on various plants may continue for four to six weeks. Damage can be especially heavy in sandy areas, the preferred habitat for egg-laying. A toxin present in the beetles may kill poultry. Management Adult chafers begin emerging in late May and early June at the time of grape bloom.