Photographer:Tiwago Affiliation:USGS Bee Inventory and Monitoring Lab Source:www.flickr.com Copyright: CC BY 2.0
Popillia japonica is an oval-shaped, metallic-green with bronze wings beetle that is about .5 inches long. Unfortunately, in the family Scarabaeidae contains thousands of beetles that are very similar in appearance, so the Japanese beetle can be easily over-looked. However, the larvae of Popillia japonica can be distinguished by a C-shaped growth and a V-shaped row of spines beneath the abdomen.
Host Plants: Leaves, flowers and fruits of hundreds of different plants including shrubs, trees, vines and perennial and annual herbs including crops.
Since these beetles have a non-discriminating palate they can cause severe damages to hundreds of plants. Fruits such as grapes can be entirely consumed and the vines destroyed. Also, corn can be damaged when the beetles eat the silk and prevent the formation of kernels. The larvae damage patches of lawns and other grasses when the numbers are high. Also, when the Japanese beetle is present and feeding on fruit it can facilitate aggregation and fruit injury by the native green June beetle Continis nitida. This means the Japanese beetle is not only a threat by itself but causes native June beetles to increase their damage capabilities.
For the Homeowner’s guide compiled by APHIS for identification and management of the Japanese beetle, click here
Adults emerge in early summer and congregate on plants for mating. Over the course of summer females can lay 40-60 eggs each and the eggs are deposited in the soil 3-4 inches deep. The larvae hatch out about two weeks later and begin to feed on plant roots, and remain there over-winter if needed. When temperatures raise the larvae pupates and, in 8-20 days they emerge as the next generation
Popillia japonica was first discovered in a nursery in Riverton, New Jersey in 1916. It is thought that the grubs contaminated shipments of iris bulbs before 1912, when the United States started inspecting imports. In the next 60 years it spread throughout 22 states east of the Mississippi River. So far, west of the Mississippi only a few states have isolated populations and “hitchhikers” on aircraft to the western states are continuously intercepted, which these beetles could cause a serious issue in western orchards and truck farms.
U.S. Habitat: Not limited to forests or grasslands and can live in rural and urban areas including household gardens.
U.S. Present: AL, AR, CT, DE, GA, IA, IL, IN, KS, KY, MA, MD, ME, MI, MO, MN, NC, NH, NJ, NY, OH, OK, PA, RI, SC, TN, VA, VT, WI, WV
There are several biological controls that have proven effective against the larvae. One biological control is the milky spore bacterium, Bacillus popillae, which is applied to the turf and can reduce populations for decades if properly used. Nematodes (Heterorhabditis spp.) also work well in destroying larvae. Commercially available traps lure the beetles away from plants but may also attract other beetles into a yard. Landscape planting of non-palatable plants such as juniper, holly, forsythia, boxwood, and spruce can also deter the beetles from massing in suburban populations.
Hammons, D. L., Kurtural, S. K., Newman, M. C., & Potter, D. A. 2009. Invasive Japanese beetles facilitate aggregation and injury by a native scarab pest of ripening fruits. Proceedings of the National Academy of Sciences, 106(10):3686-3691.
Hammons, D. L., Kaan Kurtural, S., & Potter, D. A. 2010. Impact of insecticide‐manipulated defoliation by Japanese beetle (Popillia japonica) on grapevines from vineyard establishment through production. Pest management science, 66(5):565-571.
Morris, E. E., & Grewal, P. S. 2011. Susceptibility of the Adult Japanese Beetle, Popillia japonica to Entomopathogenic Nematodes. Journal of nematology, 43(3-4):196.
Petty, B. M., Johnson, D. T., & Steinkraus, D. C. 2012. Survey of Pathogens and Parasitoids of Popillia japonica (Coleoptera: Scarabaeidae) in Northwest Arkansas. Journal of invertebrate pathology.