Signup to receive email updates

or follow our RSS feed


John Fulton

John Fulton
Former County Extension Director

Blog Archives

732 Total Posts

follow our RSS feed

Blog Banner

In The Backyard

Horticulture columns and tips done on a timely basis
Japanese beetle

First Japanese Beetles of 2011 Sighted

Posted by John Fulton -

With the warmer weather, it was bound to happen. The first Japanese beetles of the season were captured on June 16 in a pheromone trap north of Lincoln

Japanese beetle adults have a 1/2 to 3/4 inch long body with copper colored wing covers and a shiny metallic green head. A key characteristic is prominent white tufts of hair along their sides. They also have an overwhelming appetite for your favorite rose. Adults feed in herds on many deciduous trees, shrubs and vines such as linden, Japanese maple, sycamore, birch, elm, and grape. They generally do not feed on dogwood, forsythia, holly and lilac. Japanese beetle adults feed on flowers and fruits and skeletonize leaves by eating the leaf tissue between the veins. Feeding is normally in the upper portions of trees. Beetles prefer plants in direct sun, so heavily wooded areas are rarely attacked.

Adults can be with us until mid August. The life cycle is similar to a June bug, only it runs a few weeks later. After mating, females lay eggs in turf which hatch into grubs in August. Grubs feed on plant roots until cold weather drives them deeper into the soil. Adults emerge in summer of the following year.

The bacterial control, milky spore sold as Doom or Grub Attack, is frequently recommended to control Japanese beetle grubs. In our area milky spore is generally not recommended, since it controls only Japanese beetle grubs and not our predominate lawn grub, the annual white grub. Also Japanese beetle grubs must already be infesting the turf for milky spore to work effectively. Pesticides commonly used for lawn grub control will also control Japanese beetle grubs.

Controlling Japanese beetle grubs does not significantly reduce the number of adult beetles the following year. The beetles are good fliers, and easily fly a couple miles in a single flight. Evidence suggests that adult beetles are attracted to previously damaged leaves. Therefore reducing feeding damage now can result in less feeding damage in the future. Picking beetles off ornamental plants, or early chemical controls, will help prevent the pheromones from being released to attract others to the same area.

Please share this article with your friends!
Share on Facebook Tweet on Twitter Pin on Pinterest