Is there a landscape pest worse than the Japanese beetle? First the beetle grubs destroy your lawn, and then the adult beetles emerge to feed on your leaves and flowers. Knowledge is power when it comes to defeating this pest in your yard. Learn to identify the Japanese beetle, and how it's life cycle impacts your plants.
Description:
The Japanese beetle's body is a striking metallic green, with copper-colored elytra covering the upper abdomen. An adult beetle measures just about 1/2 inch in length. Five distinctive tufts of white hairs line each side of the body, and two additional tufts mark the tip of the abdomen. These tufts distinguish the Japanese beetle from other similar species.
Japanese beetle grubs are white, with brown heads, and reach about 1 inch in length when mature. First instar grubs measure just a few millimeters in length. The grubs curl into a C shape.
Classification:
Kingdom - Animalia
Phylum - Arthropoda
Class - Insecta
Order - Coleoptera
Family - Scarabaeidae
Genus - Popillia
Species - Popillia japonica
Diet:
Adult Japanese beetles are not picky eaters. They'll feed on both the foliage and flowers of several hundred species of trees, shrubs, and herbaceous perennials. The beetles eat plant tissues between the leaf veins, skeletonizing the foliage. When beetle populations get high, the pests may completely strip a plant of flower petals and foliage.
Japanese beetle grubs feed on organic matter in the soil and on the roots of grasses, including turfgrass. High numbers of grubs may destroy turf in lawns, parks, and golf courses.
Life Cycle:
Eggs hatch in late summer, and grubs begin to feed on plant roots. Mature grubs overwinter deep in the soil, below the frost line. In spring, grubs migrate upward and resume feeding on plant roots. By early summer, the grub is ready to pupate with an earthen cell in the ground.
Adults emerge from late June into summer. Adults feed on foliage and mate during the day. Females excavate soil cavities several inches deep for their eggs, which they lay in masses. In most parts of its range, the Japanese beetle life cycle takes just a year, but in northern areas it may stretch to two years.
Special Adaptations and Defenses:
Japanese beetles travel in packs, flying and feeding together. Males use highly sensitive antennae to detect and locate female mates.
Habitat:
With such a variety of potential host plants, Japanese beetles are well suited to live just about anywhere. Popillia japonica inhabits forests, meadows, fields, and gardens. Japanese beetles even find their way to urban backyards and parks.
Range:
Native to eastern Asia, this beetle was accidentally introduced to the U.S. in 1916, and is now established throughout the eastern U.S. and parts of Canada. Intermittent populations occur in the western U.S.
