The Japanese beetle is a persistent and destructive pest that gardeners and farmers must actively manage to prevent extensive damage to plants and crops. By understanding their lifecycle and implementing a combination of biological, cultural, and chemical controls, it is possible to reduce the impact of these invasive insects on landscapes and agriculture.
Japanese Beetle 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 or Damage of Japanese Beetles
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.
How to Control Japanese Beetles
Effective Japanese beetle control requires treating both the immature larvae and adult beetles. Where these pests are prevalent, preventive and active treatment are essential.
Japanese Beetle Control 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 thoroughly and follow instructions, including guidelines for listed plants and pests, application frequencies and pre-harvest intervals (PHI) for edible crops.
