Strawberries: Plants attacked by tiny worms
Question: I have grown strawberries for many years. Three years ago I started a new bed with all new plants. Every year some of the fruits on these plants are attacked by tiny worms which look just like pieces of straw. Is there is anything I can do? (Mrs P Pearce, Great Witchingham)
The only thing I can think it could be is the larvae of a beetle such as the grubs of raspberry beetle. It is mainly a problem on summer-fruiting raspberries. Damaged ripe berries have greyish-brown dried up patches at the stalk end
A brownish-white grub, up to 8mm long, may be found inside the fruits. The 4mm long adult beetles are pale brown and lay eggs on the flowers in May to mid-July. The young larvae feed at the stalk end of the developing fruit, but later move inside to feed on the central plug. In late summer, the fully-fed larvae move into the soil where they overwinter as pupae.
Pyrethrum (Py Spray Garden Insect Killer, Bug Clear Gun for Fruit & Veg, and Doff All in One Bug Spray) can be used to control raspberry beetle. A minimum one-day interval is required between spraying and picking the fruit. A better level of control is likely with deltamethrin (Bayer Sprayday Greenfly Killer). Apply insecticides in the evening when bees are not active on the flowers. Derris/rotenone is no longer available for use as a garden insecticide.