Kansas State University


Extension Entomology

Green June Beetle Adults

–by Dr. Raymond Cloyd

Green June beetle, Cotinis nitida, adults are actively flying around in massive numbers near managed and/or unmanaged grassy areas, and ‘bumping’ into people and objects. Adults are 3/4 to 1.0 inch long, velvety-green, and tinged with yellow-brown coloration (Figure 1). Green stripes with yellow-orange margins extend lengthwise on the front wings. The underside of the body is distinctly shiny and metallic green or gold. Adults resemble ‘dive bombers’ flying around for several weeks in July. Green June beetle adults are sometimes confused with Japanese beetle (Popilla japonica) adults—but they really do not look alike (Figures 2 and 3).

Fig 1. Green June Beetle Adult (Auth–Raymond Cloyd, KSU)

Fig 2. Green June Beetle Adult (Auth–Raymond Cloyd, KSU)

Fig 3. Japanese Beetle Adult (Auth–Raymond Cloyd, KSU)

Green June beetle has a one-year life cycle, and overwinters as a mature larva or grub. Adults generally emerge in late-June and are active during the day, resting at night on plants, in thatch, or in compost. Adults produce a sound similar to that of bumble bees. Adults will feed on ripening fruits and corn tassels, and may occasionally feed on plant leaves. Male beetles swarm in the morning, ‘dive bombing’ to-and-fro just above managed and/or unmanaged grassy areas where females are located. Females emit a pheromone that attracts the males. Clusters of beetles may be seen on the surface of the soil or in grassy areas with several males attempting to mate with a single female, resulting in an ‘insect orgy.’

Mated females that survive the ‘experience’ will lay clusters of 10 to 30 eggs in moist soil containing a high amount of organic matter. Eggs hatch in about two weeks, in early August, and young larvae feed near the soil surface. The larvae feed primarily on organic matter including thatch and grass-clippings; preferring material with a high moisture content. Larvae are 3/8 (early instars) to 1.5 (later instars) inches long, and exhibit a strange behavioral trait—they crawl on their back—likely due having a constant itch.



Leave a Reply

Your email address will not be published. Required fields are marked *