Blackcurrant gall midge

Blackcurrant gall midge can cause the leaves of blackcurrants to become distorted and crumpled.

Blackcurant gall midge damage

Quick facts

Common name Blackcurrant gall midge
Latin name Dasineura tetensi
Plants affected: Blackcurrant
Main symptoms Small, distorted, crumpled leaves
Caused by The larvae of a small midge
Timing Spring and summer
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What is blackcurrant gall midge?

The midge is a tiny (up to 2mm long) yellowish-brown fly. The females lay eggs between the folds of newly emerged leaves. The eggs hatch a few days later and orange-white larvae feed on the leaf surfaces for 10 to 14 days before going into the soil to pupate. Their feeding prevents normal expansion of the leaves which remain small, distorted and crumpled. Damage to established bushes is generally not serious although the distorted foliage is unsightly and may be mistaken for the symptoms of reversion disease. Young blackcurrant bushes and cuttings can suffer a more serious check in growth.

There are three generations during the summer with adult flies laying eggs in late April to early June, late June to early July, and late July to August. It is however, the first generation of larvae that is often the most damaging. The third generation of larvae, that finish feeding in August, spend the winter as pupae in the soil.

Control

Some damage from this midge can be tolerated as light infestations will not affect cropping.

Non chemical

Hoeing the soil under bushes during dry weather in the summer may destroy some of the pupae by exposing them to drying conditions. Some blackcurrant cultivars, such as ‘Ben Connan’ and ‘Ben Sarek’, are resistant to this pest. Removing affected shoots can help reduce infestation levels.

Chemical

  • Spraying at the first signs of symptoms with lambda-cyhalothrin (e.g. Westland Resolva bug killer) or deltamethrin (e.g. Bayer Provado fruit and vegetable bug killer) may reduce infestations
  • Manufactures instructions for the food crop must be followed, including harvest interval and maximum number of applications
  • Plants in flower should not be sprayed due to the danger to pollinating insects
  • Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener

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

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