Japanese Beetle

David W. Held and Daniel A. Potter

University of Kentucky

The Japanese beetle, Popilliajaponica, is among the most polyphagous of plant-feeding insects. The adults skeletonize the foliage, or feed on the flowers or fruits, of nearly 300 species of wild or cultivated plants. Favored hosts include many woody and herbaceous landscape plants, garden plants, fruits, and field crops. The larvae, or grubs, develop in the soil where they feed on roots of turf and pasture grasses, vegetables, nursery seedlings, and field crops. Hundreds of millions of dollars are spent annually for controlling the adults and grubs, and in state and federal regulatory efforts aimed at limiting the beetle's rate of spread in the United States and elsewhere.

The Japanese beetle was first discovered in the United States in 1916, near Riverton, New Jersey. How it was inadvertently transported from its native Japan is not known; however, the grubs may have arrived in soil around the roots of nursery plants. The species is not a major pest in Japan, where suitable grassland habitat is limited and natural enemies keep this beetle in check. The eastern United States, however, provided a favorable climate, with abundant moist turf as habitat for the eggs and larvae, numerous adult food plants and, at that time, no host-specific natural enemies. Populations increased and spread rapidly. By 2000, the beetle was established in all states east of the Mississippi River except for Florida, and in parts of Wisconsin, Minnesota, Iowa, and Nebraska. It also has spread north into southern Ontario and Quebec, Canada.

0 0

Post a comment