COUNTY AG NEWS
Rose chafers are one of the insect pests that people are blessed with here in Waushara County, and they are beginning to show up in area fields and local gardens.
Rose chafers are a type of scarab beetle that are found in sandy areas of the state. In June, adult beetles appear and feed on a wide variety of plants. Adult rose chafers feed on grapes, fruit trees, roses, raspberries, and many flowering plants. Leaves are often left skeletonized with veins and small amounts of tissue left behind.
An adult rose chafer is a moderate-sized insect, measuring between 5/16-inch to almost 1/2-inch in length. It’s a slender beetle, pale green to tan in color with longer, reddish brown or orangish spiny legs. It has short, lamellate antennae.
Adults appear during the early part of June and live about three weeks. They can fly considerable distances in search of plants to feed on. Many times, large numbers of beetles will be concentrated on a single plant. Adult beetles feed on plants for three or four weeks, generally until late June. This year since it has been a cooler than normal spring they should be around until the middle of July. Females lay eggs in the soil, then die shortly afterwards. Two to three weeks later, the eggs hatch into small, white grub like larvae which feed on the roots of grasses and weeds. The larvae spend the winter in the soil below the frost line. They pupate the following spring and then emerge as adults. There is one generation a year.
Grubs do no economic damage and feed on the roots of plants in old fields, pastures and other open areas. Grubs are in the soil and are not found in lawns. Most feeding is on weeds and non crop plants.
Rose chafers contain a toxin that can be deadly to birds, including chickens, and small animals when they eat these beetles.
Plants can be sprayed with insecticides containing carbaryl (Sevin), meth-oxychlor, or permethrin. These will likely need to be reapplied every three to four days.
Valuable plants can be covered with insect barrier netting such as cheesecloth, floating row cover or other materials. This will force the beetles to look elsewhere for food.
A commercial rose chafer trap can be used to draw beetles away from plants. Place traps 30 feet away from plants that need protection and use one trap per 200 ft of yard perimeter. This is a type of Japanese beetle trap with a special rose chafer attractant.