Raspberry beetle
The raspberry beetle lays eggs in flowers, and its larvae feed on the ripening fruit, leaving hardened, greyish-brown patches at the stalk end. Grubs are often found in picked fruit.
Pests
What it looks like
Damage sits at the stalk end.
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Dry patches Grey-brown, hardened drupelets near the stalk. -
Grubs Pale brown larvae up to 8 mm long inside the fruit. -
Damaged flowers Adults feed on blossom in spring. -
Small beetles Brown beetles about 4 mm long on flowers.
How to confirm it
Check picked fruit.
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Look inside
Grubs in the plug cavity.
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Stalk end damage
Patches at the stalk rather than the tip.
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Timing
Summer-fruiting varieties are hit harder.
What to do
Accept a little, or time your control.
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Pick promptly
Harvest often and discard damaged fruit.
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Cultivate the soil
Light forking beneath canes in winter exposes pupae to birds.
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Grow autumn raspberries
Autumn-fruiting varieties largely miss the beetle.
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Check in the bowl
Soak fruit briefly; larvae float out.
Prevent it next time
- Grow autumn-fruiting raspberries where the beetle is bad.
- Keep ground under canes clear and lightly cultivated.
- Encourage birds.
What not to do
Do not spray canes while in flower; bees are working them.
In the growing guides
Where the guides mention it, with plant-specific advice.
Sources
- Raspberry beetle, Royal Horticultural Society