Though strangely beautiful with their metallic green bodies and copper wings, Japanese beetles are a major pest in the eastern U.S. In fact, these insects feed on more than 300 different plant species. You’ll find adult beetles feasting throughout summer and into early fall depending on location. The pests emerge from the ground in early summer in the southern part of their range and later in June or July in more northern areas.
Their favorite “restaurants” include: Japanese maple, Norway maple, Prunus species including cherry, plum and peach, birches, lindens, elms, sassafras, horse chestnut, and black walnut. It also seems nearly impossible for them to pass up a quick bite (or thousands) of any type of rose plant. Japanese beetles prefer eating in full sun. They rarely attack plants in well-shaded areas.
Japanese beetle damage
Adult beetles feed on the upper surface of leaves. As they eat, they chew the tissue between the leaf veins. A lacelike skeleton of the leaf remains after feeding. The damage can be severe, particularly when populations are high.
Plant selection
Given their diverse feeding habits, smart plant selection is a good way to minimize visits from these unwanted guests. First, eliminate weeds that are favored beetle snacking spots. You’ll want to manage bracken, poison ivy, elder and wild grape. Second, when making additions to your landscape, consider choosing plants that Japanese beetles typically don’t eat. Some tree, shrub and plant species are simply less attractive to the beetles. While not resistant, these plants certainly be less likely hosts.
For plants seldom damaged by Japanese beetles, consider evergreen ornamentals, rhododendron, white or green ash, red or silver maple, and tuliptree. Many oaks (white, scarlet, red, and black), sweetgum, and hickory are also generally less favored but may see occasional damage.
