Latin name: Byturus unicolor
Reason for Concern:
1) Economically important northern Washington and British Columbia.
2) Adult beetles reduce yield by feeding on unfolding leaves and blossom clusters.
3) Larvae feed within flowers and burrow between the core and the berry flesh.
4) They can be a contamination problem at harvest.
Formerly called the Western Raspberry Fruitworm, the Raspberry Beetle is small and brown, eats holes in terminal leaves and devours blossoms often injuring plants. Adults are light brown, somewhat flattened, covered with short hairs, and about 1/6" long. They leave a distinct feeding pattern on the leaves. Larvae, about ¼” long, often adhere to picked fruit. They have short legs and are light yellow with a cross band of light brown on the back of each segment.
Adult beetles overwinter in soil, emerging in spring to feed on fruit buds and unfolding leaves. Females lay eggs in May on the base of the blossom buds or on green fruit. Larvae work and develop inside the fruit and the fleshy receptacle, often causing fruit to dry up. Some feed until harvest. Most larvae mature, leave the berry and drop to the ground where they enter the soil and pupate. Adults form in late summer and overwinter.