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Friday, May 6, 2016

Green June Beetles are a threat to produce

Friday, July 27, 2012

A pack of green June beetles converge to devour a ripe peach. Green June beetles feast on blackberries, raspberries, peaches, early grapes and even corn and tomatoes.
I know some people have fond childhood memories of tying a thread to the leg of a green June beetle and letting them fly in a circle above their heads. Unfortunately at the Missouri State Fruit Experiment Station, we aren't fond of Cotinus nitida one little bit.

Green June beetle adults are velvety-green with orange or rust stripes along the outer margins of the wing covers. Beetles may be 1/2 to 1 inch long, larger and more massive than Japanese beetles. The green June beetles are not strong fliers as you can see when they emerge from the ground and fly only short distances. They are voracious eaters, however, as if to make up for their shortcomings in flight. Green June beetles feed on ripe fruit including peaches, blackberries, raspberries, apples, grapes and even sweet corn and tomatoes. They buzz when disturbed from eating and sound like bees, and can cause quite a scare.

Green June beetles have one generation per year (thank goodness) and overwinter as grubs in the soil. The grubs pupate in cells in the soil during late April and May and remain at this stage for 2 to 3 weeks. Newly emerged adults remain in the soil for another week or two and leave the soil beginning in later May and continue through August, although peak emergence occurs from June through July.

Female beetles fly over the grass surface in early morning to daybreak and male beetles fly during mid- to late morning. Female beetles produce substances that attract males for mating. After mating, the females construct a walnut-sized ball of soil and lays from 10 to 30 eggs in it, up to 75 eggs in a two week period. Eggs hatch in about two weeks and then the young grubs begin to tunnel through the soil, but they also feed on the soil surface.

Immature grubs of the green June beetle cause their share of damage too. They gnaw on grass roots and prefer sandy or sandy loam soils with high organic matter. The green June beetle grubs are different from most of the other grubs in that they come out of the ground at night and move from one place to another. They crawl on their backs with their legs up in the air, and if disturbed, will curl up into a C-shape.

If you decide to battle these beetles on your fruits and vegetables with a pesticide, you may choose to purchase a general use insecticide, like carbaryl (Sevin), to use. Be certain to read the label to make sure you are using an insecticide that is labeled for the crop that you are applying it to as well as the pest that you are targeting.

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