Currant blister aphid

Currant blister aphid is a common pest of red, white and black-currants. The distorted growth is very noticeable, although the plant’s vigour and ability to bear fruit is not greatly affected.

Currant blister aphid

Quick facts

Common name Currant blister aphid
Scientific name Cryptomyzus ribis
Plants affected Red, white and blackcurrants
Main symptoms Leaves at the shoot tips are puckered, often with reddish or yellowish green discoloration. Pale yellow aphids may be seen on the lower leaf surface
Most active Late April-June

What is currant blister aphid?

Currant blister aphid is a sap-sucking insect that infests the lower leaf surface in early summer and causes leaf distortion on currant plants.

Symptoms

  • Leaves at the shoot tips appear puckered or blistered
  • The distorted foliage takes on a reddish or yellowish green discoloration
  • Pale yellow aphids can be found underneath the blistered areas in late spring-early summer

Control

Non-chemical control

  • Currants affected by blister aphid still make growth and produce a crop, and treatment is not essential

Chemical control

  • If desired, plants can be treated with a plant oil winter wash (e.g. Growing Success Winter Tree Wash or Vitax Winter Tree Wash) in December to reduce  the number of overwintering eggs
  • Provided the manufacturers instructions are followed insecticides approved for spraying on currants against newly-hatched aphids shortly after bud burst are the systemic insecticide thiacloprid (e.g. Bayer Provado Ultimate Bug Killer), contact sprays deltamethrin (blackcurrant only - e.g. Bayer Provado Ultimate Fruit & Vegetable Bug Killer),  lambda-cyhalothrin (e.g. Westland Resolva Bug Killer) or organic sprays, such as pyrethrum (e.g. Py Spray Garden Insect Killer, Defenders Bug Killer or Bug Clear Gun for Fruit & Veg)
  • There is no point in spraying after the foliage has become distorted
  • Do not spray while the currants are in flower due to the danger to bees and other pollinating insects

Download

Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Biology

  • Currant blister aphids are pale yellow and live on the underside of the leaves where they feed by sucking sap
  • They also secrete chemicals into the foliage and this causes puckering, distortion and discolouration
  • Other species of aphid also occur on currants but they do not produce this characteristic blistering symptom. 
  • Wingless forms of the blister aphid are active on currants from bud burst until July
  • In midsummer, winged aphids develop and migrate to the wild flower known as hedge woundwort (Stachys sylvatica)
  • Infestations on currants come to an end at that time, although damaged foliage remains visible until leaf fall
  • The aphids return to currants in the autumn when overwintering eggs are laid

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