Pest Profile: Japanese Beetles

Although beautiful with bright green coloration, the Japanese beetle is a widespread and destructive pest of turf, landscape, and ornamental plants in the United States. It is also a pest of several fruits, garden and field crops, and a host of about 300 different species. They feed on foliage, flowers, and fruits. Their damage can be characterized by the leaves of affected plants being skeletonized with only the tough network of veins left. Their larvae, also known as white grubs, are responsible for damaging the roots of grasses.

The Most Widespread Common Pest

This beetle is currently the most widespread pest of turfgrass and is responsible for almost $450 million in damage every year. Japanese beetles are found in a number of different countries including Japan, China, Russia, Portugal, Canada, and the United States. Since the original introduction in the U.S to New Jersey, this beetle has been found in a number of different states all across the country.

The adult Japanese beetle is an oval-shaped beetle 8-11 mm long and is metallic green with bronze or coppery brown wing covers that do not cover the entirety of the abdomen. The five patches of white hairs on each side of the abdomen are another distinguishing feature of this insect. Their larvae are white grubs covered with scattered long brown hairs interspersed with short, blunt spines. The larva is C-shaped when at rest. Their lifecycle is about 1 year on average, but in cooler climates, it can be as long as 2 years. Adults will emerge in mid-May, and in cooler states, they will emerge anywhere between June and July.

When Japanese beetles are found around your home or business, management is necessary because of the immense damage they can cause to plants. Beetles can be physically removed and/or caught in traps to reduce their numbers. Soil rotation and host plant removal can also help in controlling and/or reducing the population of these beetles. Or, you can call a pest professional to help control and remove these pesky beetles.

Kristen Stevens, BCE