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Bean weevil
Sitona spp.
PestLow impact
Adult weevils that notch distinctive U-shaped bites from the leaf margins of bean plants. Rarely causes serious harm to established plants, but heavy damage to seedlings can be more significant. The larvae feed on root nodules.
Outside typical active season.
Key facts
- Type
- Pest
- Affects
- Bean
- Active season
- Apr - Jul
- Peak season
- Apr - May
- Vulnerable stages
- Sown · Transplanted · Growing
- Spread rate
- slow
- If confirmed
- Monitor
Signs & symptoms
- -distinctive scalloped or U-shaped notches along leaf margins
- -damage appearing on multiple leaves simultaneously
- -small grey-brown weevils visible on plants at dusk
Management
Do now
- -Shake plants over a white sheet at dusk to collect and remove adults
- -Net young seedlings to protect them during vulnerable early stages
Prevention
- -Protect newly transplanted seedlings with fleece or fine netting for the first few weeks
- -Damage on established plants is rarely serious enough to require active intervention
Further reading
- -The characteristic leaf notching is unmistakable - U-shaped bites from the margins, not holes in the leaf surface
- -Adults emerge from overwintering in the soil in spring and migrate to bean crops