How to Control Japanese Beetles
What is metallic green and copper, attracted to a wide number of plants, and known to “skeletonize” or devour all but the veins of its favorite plants? The answer, of course, is the highly destructive Japanese beetle.
Experts believe Japanese beetles made their way from Japan to America via New Jersey, coming over as grubs in the soil of Japanese iris roots. The adults are usually just under a half-inch long, with bright green bodies and copper brown wings. Like other beetle species, the larvae (or grubs) of Japanese beetles overwinter in the soil, eating the roots of plants, especially grasses.
Here’s How to Protect Your Plants From Japanese Beetles
- Choose varieties they don’t like. In spite of their wide appetite for most types of plants, there are plenty that Japanese beetles simply do not like. Ask your local extension agency for a list specific to your region.
- Plant geraniums. While Japanese beetles appear to love munching on the petals, doing so will actually cause them to become paralyzed for several hours. Unable to move, the beetles fall off the plant and lie exposed to both hungry predators and savvy gardeners, who make quick work of them.
- Use an insecticide. Do it at the first sign of infestation, and be especially careful not to miss any new shoots and the undersides of the leaves. For vegetable plants (up to a day before harvest), use Ortho® Insect, Mite & Disease 3-in-1 Ready to Use. For trees and shrubs (including fruit trees), use Ortho® Insect Killer Tree & Shrub Concentrate. To protect roses and other flowers, choose Ortho® Insect Killer Rose & Flower Ready-to-Use. As always, follow the directions on the label.
- Cover your garden. Place a light row cover over your plants. This will allow light and water through, but keep the beetles out. (If your plants require pollination, though, you’ll need to remove the cover once they start to flower.)
- Pick them off. Of course, if you see just one or two Japanese beetles on your plants, you can simply pick them off and drop them in a bowl of soapy water or freeze them.