Description
The European chafer beetle (Amphimallon majale) is an invasive pest. The larvae feed on grass roots, destroying turf and causing extensive damage to lawns. The larvae have a strong scent which attracts predators such as crows, skunks and raccoons that further damage lawns as they dig for the larvae. Grubs actively feed during the spring and fall. Adults are ½ inch long, brick red or tan in color. The underside of the thorax is covered in white fluffy hair. Larvae are ¼ to 1 inch in length, with a dark brown head, C-shaped body and 6 conspicuous legs.
Native to Europe, the beetle was discovered in Rochester, NY in 1940, found in British Columbia in 2001 and was first detected in Washington State near SeaTac in 2015. It spreads through flight, infested nursery stock, and transport of soil and lawn debris.
Target Crops
Primarily a pest of home lawns, golf courses and turf farms, the European chafer will also feed on roots of agricultural and ornamental crops.
Life Cycle
The European chafer beetle has one generation per year. Larvae pupate in the soil, and adults emerge in June for 1-2 weeks to mate and lay eggs. Adults do not feed and usually do not fly far from where they emerged. They emerge at dusk, often swarming around trees. The eggs are white and laid individually in small cells in the soil. Each female may lay 25 eggs which hatch in about 3 weeks, usually in July-August. Larvae feed on the roots of turf. Grubs overwinter just below the soil surface and return to the root zone to feed when soil temperatures reach 50°F for several weeks.
Beneficial Nematodes
- Heterorhabditis bacteriophora—targets and kills beetle larvae. These parasites can be applied to the soil in the spring and fall when grubs are active. Use when soil temperatures are between 61-95°F.
- Steinernema feltiae—is effective against grubs in lawn and will attack prey when soil temperatures are between 50-88°F.
- Steinernema kraussei—a beneficial nematode species for cooler temperatures. Kraussei is active against beetle grubs between 40-86°F.
Insecticide Options
Insecticides are most effective against newly emerged young grubs in July-August. Effectiveness tends to decline against older, larger grubs in September through November.
- LalGuard M52—A broad spectrum biological pesticide. Available in liquid or granular.
- Insecticides with Bacillus thuringiensis var. galleriae (Btg) such as grubGone!
Cultural Control Tips
- Prevention is the best approach. Keep lawn healthy with proper irrigation and fertilization.
- Overseed in fall and spring
- Keeping lawns well-watered will discourage females from laying eggs as they prefer drier soils. Egg laying season is June-July.
- Treatment will depend upon time of year and the insects stage of development.
Look Alike Beetles
From the Minnesota Dept. of Agriculture
European chafer adults are about a half inch long and tannish in color. They are similar to the “June bugs” commonly found in Minnesota in early summer but are generally a bit smaller and lighter in color.
Larvae have the typical C-shaped appearance of white grubs and can range from ¼-inch to 1-inch long with a dark brown head and conspicuous legs. The grubs may be distinguished from other white grubs through characteristics of the posterior of the abdomen, but an experienced entomologist may be needed.
Further Resources
European chafer beetle in Metro Vancouver
European chafer in your lawn, City of Richmond, BC
Beetle ID Chart - Minnesota Department of Agriculture