Adults make long, narrow slits in blossom buds and newly formed leaves. Larvae feed in berries. In Northern United States. Adult raspberry fruitworm beetles overwinter in soil around host plants, emerging in spring. The beetles begin feeding on tender new leaves and, later, on flower buds.
Females deposit eggs on or inside flower buds or young fruit.
Larvae bore into fruit and fall to the soil where they pupate when fruit ripens. Remove damaged and rotting berries as soon as possible. Treat with a registered insecticide, starting when flower buds appear and make the second application just before blooming. Because pesticide labels can change rapidly, you should read the label directions carefully before buying and using any pesticides. Regardless of the information provided here, you should always follow the latest product label when using any pesticide.