Japanese beetles are invasive insects that originated in Asia. The natural predators that keep them in check overseas don't exist in the United States. As a result, these extremely destructive pests are steadily increasing their U.S. range. Voracious eaters, they attack a wide variety of edible and ornamental plants, including roses, vines, vegetables, shrubs and trees. In their immature larval form, Japanese beetles are destructive grubs that feed on the roots of lawn grasses.
Identification: Adult Japanese beetles are striking pests about 1/2 inch in length. Their oval-shaped, metallic-green bodies have metallic-bronze wing covers. Tiny tufts of white hairs run along each side of their abdomens. The larvae are whitish, semitransparent, 1-inch-long grubs that curl up into a "C" shape when disturbed.
Signs/Damage: Japanese beetles often feed in large groups in sunny, well-irrigated areas. The adults skeletonize leaves, feeding on tissue between the leaf veins, leaving a patchwork of holes and a lace-like remnant. They devour buds, flowers and fruit as well. Japanese beetle grub damage shows as brown, dying patches in lawns. With heavy infestations, you can roll turf back like a carpet, revealing grubs beneath.
Control: Effective Japanese beetle control requires treating both the immature larvae and adult beetles. Where these pests are prevalent, preventive and active treatment are essential. GardenTech® brand offers several highly effective products that kill these pests by contact and keep protecting lawns, edible gardens and plants for up to three months:
- Sevin® Insect Killer Granules kill and control Japanese beetles and grubs, above and below the soil line. Apply the granules with a regular lawn spreader, according to the recommended label rate, then water immediately to release the active ingredients into the soil.
- Sevin® Insect Killer Ready to Use is ideal for treating individual plants or smaller garden areas where you see or expect Japanese beetle damage. The adjustable nozzle allows you to control the width of the spray for targeted treatment.
- Sevin® Insect Killer Concentrate offers a simple, economical alternative for extensive coverage of larger garden areas. Use the easy measuring cap with a pump-style sprayer. Spray to cover all plant surfaces thoroughly.
- Sevin® Insect Killer Ready to Spray attaches to a common garden hose and automatically measures and mixes with hose water as you spray. This product simplifies coverage of larger plants, lawns and larger garden areas.
Tip: Japanese beetles are sluggish until the sun warms them. Collect and dispose of slow-moving beetles in the morning. Shake affected plants over a plastic sheet. Then dump fallen beetles into a bucket of warm, soapy water, where they'll drown.
Always read product labels and follow instructions carefully, including guidelines for pre-harvest intervals on edible crops.
GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.
Sevin is a registered trademark of Tessenderlo Kerley, Inc.
- "Japanese beetle (Popillia japonica)" by John A. Weidhass at Virginia Polytechnic Institute and State University (Bugwood.org) licensed under CC BY 3.0 US
- "Japanese beetle (Popillia japonica)" by Mike Reding and Betsy Anderson at USDA Agricultural Research Service (Bugwood.org) licensed under CC BY 3.0