The green June beetle (Cotinis nitida) feeds on fruit and foliage of all fruit trees, particularly stone fruits and apple, as well as some berries (raspberry and blackberry). It is sometimes mistaken for the Japanese beetle, which is smaller in size.
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Appearance:
Larger and more robust than its close relative (Japanese Beetle), measuring from 3/4 to 1 inch in length and about 1/2 inch wide.
The color varies from dull brown with irregular stripes of green to uniform velvet green, the margins of the body being usually light brown varying to orange yellow. The lower surface is metallic greenish or yellow, or metallic dark brown with a yellow green tint.
The larva is a typical white grub with a brown head and three pairs of short legs, but it is not as often found curled into a C-shape as are most white grubs. They are about 2 inches long when mature. Live larvae are easily distinguished by their habit of crawling on their backs.
Life Cycle:
Overwinters as a nearly mature larva in the soil. They feed and finish maturing in the spring and pupate in a cell in the soil.
A few beetles may emerge in late May or early June, but most do not emerge until mid-June.
They are common in July and August and some remain active through early October.
Eggs are laid in late summer. The eggs hatch in about 2 weeks and the larvae feed on organic matter and plant roots in the soil until winter approaches. There is one generation per year.
Damage:
Most injury occurs in mid-to-late summer.
Adult beetles damage fruit by feeding on ripening fruits.
Beetles gain entry into undamaged fruits by gouging with the horn on the front of the head, then feed on the flesh of the fruit.
Their odor and excrement ruin most pieces of fruit they visit even if feeding damage is not severe.
Management:
Feeding damage from adults is sporadic and transient during the summer. If leaf damage is observed or the insects feeding on foliage are noted in the trees, consider treating with a holistic spray or parasitic nematodes. Also, encourage populations of parasitic wasps like Scolia dubia.
Harvest fruit promptly when ripe, and remove overripe fruit.
In most years, the best time for grub control is August through October. Any of the pyrethroids are effective for controlling the grubs.
Sources: OSU Ag. Science and UGA Extension, Patrick L. Byers, Horticulture Specialist, and Michael Phillips, “The Holistic Orchard.” (Additional photo source-P. Shearer, Rutgers University).