Japanese Beetle Established in Central Missouri

The Japanese beetle (Popillia japonica) is about ½ inch long with a shiny metallic-green body and bronze-colored outer wings. The beetle has a row of five lateral tufts on each side and one each on the last segment of the abdomen. This distinguishes it from any other beetle that might be encountered in or around the urban or agricultural environment. It was accidentally introduced from Japan in 1917 and established itself throughout the eastern and southern United States and as far west as the Mississippi River. It crossed the river in 1934 at St. Louis and has maintained established populations since then. At present it can be found in most east central (St. Louis), west central (Kansas City) and southwest (Springfield) counties but not in between these areas. Because the beetle was not established in the central part of the State, a Japanese beetle survey trap was placed at a site in Boone County (Columbia) in 1996. Specifically, the trap was placed on a pole in a grassy area about 20 yards below the 13th green at the A.L. Gustin Golf Course. The location was in close proximity to corn and soybean research plots at the UMC Rollins bottoms, an ideal habitat to trap beetles if they were present.

The numbers of beetles trapped each year at the site was as follows: 0 in 1996 and 1997; 1 in 1998; 4 in 1999; 0 in 2000; 4 in 2001 and 15 in 2002. The number trapped in 2002 and the ones from previous years clearly indicate establishment of the beetle in central Missouri. Further evidence of establishment is the increase in beetles trapped this year (2003). To date over 50 beetles have been caught with the first ones appearing June 20, two weeks earlier than past years.

Beetle larvae feed exclusively on the roots of grasses while the adults have been known to feed on at least 300 species of plants by skelatonizing the leaves. At the survey site, no damage to fairway turf or nearby plants at the golf course has been detected, nor has any been reported to our Department or the MU Diagnostic Clinic.

Based on past history it is evident that in time the beetle could become an urban pest in central Missouri. Should this occur, labeled pesticides are available to control both adults and larvae of the beetle. Biological controls may also be available in the near future. These include utilizing a parasitic wasp Tiphia vernalis, a fly Istocheta aldrichi, as well as the milky disease pathogen and nematodes.

Japanese Beetle

Ben Puttler, Assistant Professor Emeritus of Entomology, UMC (573) 882-1457