They have returned. Japanese beetles. Feeding on over 300 species of plants, they are one of the most widespread, and potentially devastating, insect pests homeowners deal with.

Japanese beetles are characterized by their metallic green color and coppery wing covers. They are distinguished from the Green June beetle by their smaller size (Japanese beetles are just over a half inch long - Green June Beetles may be close to an inch…) and the presence of a series of white tufts of hair that project from under their wings.

Japanese beetles typically feed in groups – large groups – often looking for any green material. Leaves are often a favorite ‘landing spot’, and they will feed on the upper surface of the leaf, leaving a lacelike or cellophane looking appearance. Flowers are often targeted, as are wounded or mushy fruit. They prefer feeding at the tops of plants, but will drop quickly to lower in the canopy if disturbed. Plants in full sun are most often targeted.

Severe damage to landscape and fruit plants can result from the large feeding groups and the length of time they are present. Individual beetles will live for 30 to 45 days. Due to emergence differences, feeding activity can occur for up to six weeks or so.

Japanese beetles seem to overwhelm most landscape plants in fairly short order, so control efforts are most effective when implemented quickly. If you find only small pockets, try killing adult beetles by shaking them from the host plant in to a jar or bucket of soapy water. Do so in the morning for best results when beetles are more sluggish.

Insecticides labeled for Japanese beetle control are numerous. Look on product labels for Japanese beetle as well as the host on which you are trying to control them. Some active ingredients include cyfluthrin, bifenthrin, cyhalothrin, and carbaryl. The pyrethroid products will usually provide protection for two to three weeks. Sevin (carbaryl) will be slightly shorter. If you want to try a product less harmful to natural control insects – of Japanese beetles or other garden pests – consider Neem products or Pyola. They can provide some level of deterrence for a few days.

Traps are an option for Japanese beetle control. Smaller traps may attract more beetles than they kill. Larger traps have been tested by the University of Missouri, showing promise on a commercial scale. For information on that research, including information on how to make your own, go to https://ipm.missouri.edu/MEG/2018/1/mass_trapping_japanese_beetles/ .