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Japanese Beetle

© Carla Goodloe

This beetle ranges mostly in the eastern half of the US but are slowly moving westward.

The adult Japanese beetle is about 1/2" long. It is shiny metallic green, with copper-brown wings. The grub is grayish white with a dark brown head and two rows of spines that form a V on the underside of the last abdominal segment. The eggs are white and spherical, and are laid in the soil. They have a 1 or 2-year life cycle with larvae overwintering in soil.

Adults feed on foilage and fruit. They fly only in the daytime and can reach distances of 5 miles. Larvae feed on grass roots. Vulnerable plants include asparagus, beans, okra, peaches, raspberries, rhubarb, leaves and silks of corn. The larvae will chew on onions and potatoes as well as the roots of beans, corn, and tomatoes.

Symptoms of Japanese beetle damage include skeletonized leaves and stems and flowers from adults, dying grasses with no apparent culprit from grubs, and plants that seem to wilt and die with no upper damage from grubs.

Dig around the plant to uproot the grubs and check to see what kind it is.

The best controls are handpicking, pyrethrum, pheromone beetle traps, beneficial nematodes, rotenone, milky spore disease, diatomaceous earth, and birds.

I find that if I go out and run a hand rake over the soil around plants, not too far down to disturb roots, I can dig up all sorts of larvae hiding out there waiting for night. I nearly lost all of my marigolds to larvae and aphids. I began to dig around them to see if I could find out what was causing the defoliation. It's grubs of some sort, but there are so many types, that I don't care what kind, I just kill them.

Be sure to pick up all rotten fruit and debris on the ground which might harbor beetles and larvae for next year's crops.

Plant varieties that are known to have little or no damage by these pests.Visit the following site for more information on this: http://www.uky.edu/Agriculture/Entomolog...

FYI: Diatomaceous earth has been stated on most bug controls articles. This is an excellent preventative control. However, even though it is a biological control, it is also not good to breathe into your lungs. It's irritating for most people. Wear a mask and eye goggles when dusting plants. It's a tedious job because you have to dust all the time. It also is not cosmetically pleasing on plants.

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