Q How do I know if my plants have currant leaf blister aphid?

A Tiny yellowish aphids feed on the lower surface of the currant leaves, causing blistered leaves, which are initially green but soon turn shades of red and purple. The foliage is often attacked when quite small, but symptoms intensify as the leaf grows. General growth, vigour and cropping are rarely affected. Red, white and blackcurrants may be attacked, but redcurrants are particularly susceptible.

Caption: Any type of currant can be affected by currant leaf blister aphid

Q What can I do if my plants have currant leaf blister aphid?

A The symptoms may look dramatic but have little, if any, effect on the plant, so control is not necessary. Spraying with a suitable insecticide shortly after bud burst will reduce aphid numbers, as will the introduction of ladybirds.

Q How can I prevent currant leaf blister aphid?

A These aphids migrate to hedge woundwort plants in mid-summer, then migrate back to the currants to produce overwintering eggs, so removing these plants may help to reduce the problem.