Blackcurrant gall midge

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

Blackcurrant 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

What is blackcurrant gall midge?

Blackcurrant gall midge is a tiny (up to 2mm long) yellowish-brown fly. Feeding by the flies larvae causes leaves to become distorted and crumpled. 

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 usually 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


Check blackcurrants frequently from spring onwards so action can be taken before a damaging infestation has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.
 

Non-pesticide control

  • Damage from this midge can often be tolerated as light infestations do not affect cropping
  • 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 midge. Removing affected shoots can help reduce infestation levels

Pesticide control

  • At early signs of damage persistent contact-action insecticides can be used. These include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
Follow label instructions when using pesticides. On edible plants make sure the food plant is listed on the label and follow instructions on maximum number of applications, spray interval and harvest interval.
Plants in flower should not be sprayed due to the danger to bees and other pollinating insects
Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home garden

Download

Pesticides for gardeners (pdf document)

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