Species and Origin: Japanese beetles are native to northern Japan. They were first found in the U.S. in New Jersey in 1916. They have become established in parts of Minnesota.
Impacts:Adult Japanese beetles feed on more than 300 species of plants, including apple, birch, cherry, crabapple, elm, horse chestnut, linden (basswood), maple, mountain ash, oak, plum, and willow trees, as well as plants such as asters, grapes, hollyhock, roses, and Virginia creeper. Adults feed from late June through August. They feed between leaf veins, giving leaves a skeletonized look.
The larvae (grubs) of Japanese beetles feed on plant roots, especially grasses. They have been known to damage turfgrass in lawns.
It is thought that healthy trees are generally able to recover from Japanese beetle feeding, but trees that are stressed from other factors (such as drought) may not recover.
Status: Japanese beetles are established in the Twin Cities metro area and have been trapped in a number of counties throughout the state.
Where to look: Look for Japanese beetles in yards and on plants that they are known to eat.
Regulatory classification (agency): There are no regulations for movement of Japanese beetle within Minnesota. Other states have regulations to prevent the movement of Japanese beetles through infested nursery stock.
Means of spread: Japanese beetles can disperse by flying. Adults can be moved on plant material, and larvae can be transported in the soil of nursery stock.
Control methods: Control methods include hand picking, protecting target plants, chemical and biological pesticides, and biological control. See Managing the Japanese beetle: A Homeowners Handbook and links below for additional information.
How can you help?
- Keep a lookout for Japanese beetles and other invasive insects.
- Take care not to move adults or larvae from site to site in soil or on vegetation.
- USDA: Managing the Japanese beetle: A Homeowners Handbook
- Minnesota Department of Agriculture Japanese beetle webpage
- University of Minnesota Extension Japanese beetle webpage
- City of St. Paul information on Japanese beetles
- Utah Japanese beetle fact sheet