Forest Pest Insects in North America: a Photographic Guide

Japanese beetle

Popillia japonica Newman (Coleoptera: Scarabaeidae)

Orientation to pest

The Japanese beetle, Popillia japonica Newman, is an invasive insect in North America (United States and Canada) that is native to Japan. It is also invasive in China, Russia and Portugal. Adults fly during the summer and may occur in large numbers, defoliating raspberries, strawberries, roses, grapes, and other plants. Adults burrow into the soil, especially in grassy areas, and lay eggs several inches underground, where larvae then develop, feeding on the roots of grass plants and damaging the turf. There is usually one generation per year and partly grown larvae in the soil are the overwintering stage.

Hosts commonly attacked

Adults defoliate a wide range of plants including grapes, roses, and various shade and fruit trees. Larvae eat the roots of grasses and are major pests of turf, especially on golf courses. Larvae can be pests in tree nurseries or on ornamental nursery stock.

Distribution

In North America, the Japanese beetle is found in most states east of the Mississippi River and the invaded area continues to expand. One important pathway by which this pest is spread is the movement of larvae in nursery stock shipped with soil. The beetle is not found in California or the Pacific Northwest states.

Images of Japanese beetle

Adult Japanese beetle David Cappaert, Michigan State University, Bugwood.org 768x512 / 1536x1024
Larva of the Japanese beetle David Cappaert, Michigan State University, Bugwood.org 768x512 / 1536x1024
Three species of white grubs to show relative size, from left to right - Japanese beetle, European chafer, and June beetle. David Cappaert, Michigan State University, Bugwood.org 768x512 / 1536x1024
Figure 1. Adult Japanese beetle, Popillia japonica Figure 2. Larva of the Japanese beetle (left); three species of "white grubs" (right) to show relative size, from left to right - Japanese beetle, European chafer (Rhizotrogus majalis [Razoumowsky]), and June beetle (Phyllophaga sp.).
The V-shaped pattern of the raster is used to identify larvae of Japanese beetles Mike Reding & Betsy Anderson, USDA Agricultural Research Service, Bugwood.org 768x512 / 1536x1024
Figure 3. The V-shaped pattern of the "raster" (a group of hairs on underside of the rear tip of larval body) is used to identify larvae of Japanese beetles
Adult Japanese beetles feeding on rose flower Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org 768x512 / 1536x1024
Adult Japanese beetles feeding on foliage of other plants Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, Bugwood.org 768x512 / 1536x1024
Turf, infested by Japanese beetle larvae and then dug up by skunks or other mammals to eat grubs M.G. Klein, USDA Agricultural Research Service, Bugwood.org 768x512 / 1536x1024
Figure 4. Adult Japanese beetles feeding on rose flower (left) and foliage of other plants (right) Figure 5. Turf, infested by Japanese beetle larvae and then dug up by skunks or other mammals to eat grubs

Important biological control agents related to this pest species

A large scale effort to achieve biological control of this pest, based on searching for natural enemies in Japan and China, was made in the 1920s and 1930s. Several parasitoids were imported and established, the most important of which were three tachinid flies (especially Istocheta aldrichi [Mesnil]) and several tiphiid wasps (especially Tiphia popilliavora Rohwer and Tiphia vernalis Rohwer). Several pathogens of this beetle were also discovered and attempts were made to turn them into biopesticides. These included the bacterium that causes milky spore disease (Paenibacillus popilliae [Dutky]) and the nematode Steinernema glaseri (Steiner). It was the study of this nematode that stimulated the development of this family of nematodes as successful biopesticides against soil insects. For a detailed history of the biological control efforts against Japanese beetle, see Van Driesche et al. (1996).

Web links for information on Japanese beetle

Articles

University of Massachusetts, PSIS/Entomology USDA Forest ServiceUniversity of Georgia Center for Invasive Species and Ecosystem HealthUniversity of Georgia