Raspberry beetle

It is the larvae of raspberry beetle that affects fruit. The larva

A young, immature stage of development. The plural is larvae.  Commonly used for insects where the early stages look very different from the adult e.g. caterpillar (larva) and butterfly (adult).

feeds at the stalk end of the fruits. It is mainly a problem on summer-fruiting raspberries. Early fruits on autumn raspberries may be damaged, but those ripening after late August are less likely to be affected.

Raspberry beetle adults are small 4 mm long pale brown beetles in the family Byturidae. There are only two species of beetle in this family found in Britain. The other species B. ochraceus looks similar to the raspberry beetle but is associated with Geum urbanum (wood avens) and does not affect garden plants. UK beetles information on Byturidae .

• Damaged ripe berries have greyish-brown dried up patches at the stalk end
• A brownish-white grub, up to 8 mm (about 1/4 in) long, may be found inside the fruits

• Where possible tolerate some beetle damage, often only a small proportion of the crop is affected. Later ripening berries tend to be less affected
• Encourage predators and other natural enemies in the garden such as birds , hedgehogs and ground beetles
• A host plant odour (karimone) water trap is available from Agralan, Harrod Horticultural and some other suppliers. This will trap both male and female beetles which may help reduce population levels

The 4 mm pale brown adult beetles lay eggs on flowers from May to mid-July. Young larvae initially feed at the stalk end of developing fruit before moving inside to consume the central plug. By late summer, fully-fed larvae transition into the soil to overwinter as pupae.