Japanese beetle (Popilla japonica)
Species and Origin: Japanese beetles are insects that are native to northern Japan. Japanese beetles were first found in the US 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 the trees: apple, birch, cherry, crabapples, 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 the leaf veins and cause leaves to get a skeletonized look.
The larvae (grubs) of Japanese beetles feed on plant roots, especially grasses. They have been known to damage turf grass 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 known to be established in the Twin Cities metro area and have been trapped in a number of counties throughout the state.
Where to look: Yards and on the 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 into their states through infested nursery stock.
Means of spread: Japanese beetles can fly and disperse. Adults can be moved on plant material and the larvae can be transported in the soil of nursery stock.
Control methods: A variety of control methods can be used including hand picking, protecting target plants, and chemical and biological pesticides, and biological control. See USDA publication 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. Larvae can be moved by moving soil. Adults can be on vegetation that is moved.
- If you are a MN homeowner and have questions, visit the University of Minnesota Extension Japanese beetle webpage.
Additional Resources
- USDA: Managing the Japanese beetle: A Homeowners Handbook
- University of Minnesota Extension Japanese beetle webpage
- University of Minnesota Extension - the beetles are coming
- City of St. Paul information on Japanese beetles
- Biocontrol (Ohio State University)
- Utah Japanese beetle fact sheet