–by Dr. Raymond Cloyd — Horticultural Entomology
Green June beetle, Cotinis nitida, adults are flying around in massive numbers near managed and/or unmanaged grassy areas, and occasionally ‘bumping’ into people and objects. Adults are 3/4 to 1.0 inch long, velvety-green, and tinged with yellow-brown coloration. Green stripes with yellow-orange margins extend lengthwise on the front wings (Figures 1 and 2).
Figure 1. Green June Beetle Adult (Raymond Cloyd, KSU)
Figure 2. Green June Beetle Adult (Raymond Cloyd, KSU)
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; however, they really do not look alike.
Green June beetle has a one-year life cycle, overwintering as a mature larva or grub in the soil. Adults typically emerge in late-June and are active during the day, resting at night on plants, in thatch, or in compost. Adults produce a sound when flying that is similar to bumble bees. Adults feed on ripening fruits and corn tassels, and may feed on the leaves of oak and maple trees. Male Green June beetles swarm in the morning, ‘dive bombing’ to-and-fro just above managed and/or unmanaged grassy areas where females are located. The females emit an odor or pheromone that attracts the males. Clusters of beetles may be seen on the soil surface or in grassy areas with several males attempting to mate with a single female. After mating, females lay clusters of 10 to 30 eggs in moist soil with a high content of organic matter. The larvae emerge (eclose) from eggs in approximately two weeks and feed near the soil surface. Larvae are 3/8 (early instars) to 1-1/2 (later instars) long and primarily feed on organic matter in thatch or grass-clippings.