Sap beetles – There are 2 members of this insect family that are a problem on raspberries. They are similar in size, appearance and damage caused to fruit. The first is the picnic beetle (Glischrochilus quadrisignatus):
The second is the strawberry sap beetle (Stelidota geminata):
Adult beetles bore into ripe and overripe fruit, feeding and depositing eggs. These insects also disseminate fruit-rotting fungi and bacteria. Late maturing varieties tend to be more susceptible to sap beetle damage as beetle populations are generally at their peak in late summer.
More information:
- Notes on Raspberry Insects – Sap Beetles – (OMAFRA)
Use these resources if you need additional help with diagnosis and to find solutions to your problem.