Adult beetles and their larvae strip the outer bark and leaves from the stem. Damaged areas become yellow-brown and desiccated. The black beetles are 6-8mm long with a red thorax and six yellow blotches on the wing cases. Larvae are grey-black in colour, 1cm (½in) long, with three pairs of legs.
Destroy overwintering beetles by burning old stems at the end of the season. From late spring, search and destroy the pests by hand. On larger plots, use sprays containing pyrethrum.
Slugs and snails:
These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers and copper tape.
Look for colonies of greenfly on the soft shoot tips of plants or on leaves. They suck sap and excrete sticky honeydew, encouraging the growth of black sooty moulds.
Use your finger and thumb to squash aphid colonies, spray with pyrethrum, insecticidal soap, plant or fish oils.