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CABBAGE ROOT FLY  (Delia radicum or radicans)


DESCRIPTION
The main symptom of the Cabbage Root Fly pest is stunted growth especially if infected as seedlings. Discoloured leaves which wilt. Roots are black and rotten.

The symptoms of Cabbage Root Fly are caused because the roots are unable to function in their normal way. The disease is caused by maggots of the Cabbage Root Fly munching their way through the roots of the plants.

 


The flies are most common in spring but they multiply so rapidly that they also appear in the summer and autumn. In good conditions (for Cabbage Root Fly anyway!) three generations can be produced in a single year.

TREATMENT
Treatment of Cabbage Root Fly is only by the spraying of chemicals, there are no known organic treatments. Either treat with chemicals or dig up all affected plants and burn them. Treatment with chemicals will not undo all the damage and reduced crops will result. We do not advise treating cabbage root fly with chemicals.

PREVENTION

Prevention of Cabbage root Fly can be achieved by placing a 15cm (6 in) diameter collar of carpet or underlay around each plant. This will prevent the fly from laying eggs on the soil near the plant. Lots of other materials can also also be used as a collar. Thick cardboard works well as does most materials which do not rot too quickly.

Burn all infected plants and do not plant brassicas on the same site for three years.

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PESTS AND DISEASES CLASSIFIED BY PLANT