Raspberry fruit worm

A common pest of raspberry is a small brown and oval shaped beetle (Byturus Bakeri), that overwinters as a pupae in the soil under the plants.  The adult beetles emerge just as raspberry leaves begin to unfold. It feeds on the leaves, leaving long angular holes or a skeletonized appearance, usually starting on the lower leaves and works its way up. It also feeds on the flower buds. It lays eggs in the flowers, which develop into larvae that feed on the flowers and the fruit.  In mid-summer, the larvae fall to the ground, burrow into the soil and overwinter as a pupa, to emerge next spring as a beetle.  Infected fruit may drop prematurely. 

Control:

• Collect infected fruit immediately and destroy.  Scout for adult beetles and destroy.
• Beetles may be vacuumed up using a shopvac.
• Damage tends to be worse on early blooming raspberry plants. 
• Shallow tilling in the fall may expose the pupae to cold and predators such as birds.

Sources:

https://www.gov.mb.ca/agriculture/crops/insects/raspberry-fruitworm.html