Cabbage root fly

Cabbage root fly
Cabbage root fly larvae on a cauliflower stem
Scientific Classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Section:	Schizophora
Family:	Anthomyiidae
Subfamily:	Anthomyiinae
Tribe:	Hydrophoriini
Genus:	Delia
Species:	Delia radicum
Risk period
J F M A M J J A S O N D
Synonyms
Cabbage fly Cabbage maggot Root fly Root maggot Turnip fly Musca radicum Linnaeus, (1758) Anthomyia brassicae Wiedemann, (1817) Chortophila floccosa Macquart, (1835) Chortophila frontalis Macquart, (1835) Aricia villipes Zetterstedt, (1845) Chortophila appendiculata Bigot, (1885) Anthomyia detergens Pandellé, (1900) Anthomyia stimulea Pandellé, (1900)

Cabbage root fly (Delia radicum), known variously as the cabbage fly, root fly or turnip fly, is a pest of crops. The larvae of the cabbage root fly are sometimes known as the cabbage maggot or root maggot. The adult flies are approximately 1cm (½in) long and are grey in colour but otherwise resemble the common house fly. Pupae overwinter in the soil close to brassica roots.

Symptoms

Growth is stunted, more-so if infected as seedlings. Roots turn black and rot and leaves are discoloured and wilted.

Treatment

Either spray with a chemical treatment or dig up all affected plants. Chemical treatment will not cure plants and a lower yield should be expected. There is no known organic treatment.

Prevention

Flies feed on pollen and nectar, particularly that of cow parsley. When cow parsley flowers the first generation of root fly are at large and preventative protection should already be in place. Putting collars around plant stems will stop the female root fly laying her eggs close enough to the plants for the maggots to reach. Alternatively; using a fine mesh over plants and beds will stop flies getting close to crops as well as providing an excellent barrier for many other crops.