A Japanese beetle is a shiny, metallic-green insect with copper-colored wings, about half an inch long, that feeds on the leaves, flowers, and fruits of hundreds of different plants. Despite their beautiful appearance, these beetles are one of the most destructive garden pests in North America.

Japanese beetles originally lived only in Japan, where natural predators kept their numbers under control. In 1916, they accidentally arrived in New Jersey, probably as larvae in a shipment of iris bulbs. Without their natural enemies, they spread rapidly across the eastern United States. Today, they cause millions of dollars in damage each year to crops, gardens, and golf courses.

These beetles have an unusual life cycle. Adult beetles emerge from the soil in early summer and feed for about six weeks, often gathering in large groups that can strip a rosebush or grapevine bare in hours. They lay eggs in the ground, which hatch into white grubs that spend the fall and winter underground, munching on grass roots. In spring, they transform into adults, and the cycle begins again.

Gardeners try many methods to control Japanese beetles: picking them off plants by hand, using traps, releasing natural predators like parasitic wasps, or choosing plants that beetles find less tasty. The battle continues every summer across much of the country.