Cabbage root fly

Definition

A small dipteran pest, Delia radicum (family Anthomyiidae), whose larvae mine the roots and hypocotyls of brassicaceous crops, causing stunting, wilting, or plant death. The adult is a drab grey fly ~6–8 mm long, resembling a diminutive house fly; the legless, tapered larvae are the destructive stage, feeding ectophytically on root cortical tissue and creating entry points for secondary pathogens. The species is holarctic and a major economic pest of cabbage, broccoli, turnip, radish, and oilseed rape, with management relying on crop rotation, resistant rootstock, insecticide-treated seed, or physical barriers such as insect-proof netting.

Etymology

From the host association (cabbage and related Brassica crops) and larval habitat (root zone).

Example

In autumn-sown oilseed rape, cabbage root fly larvae tunnel through the taproot, producing brown scarring that renders plants susceptible to wind-rock and Phoma stem canker infection.

Synonyms

• cabbage fly
• root fly
• turnip fly

Related Terms

• Delia radicum
• cabbage maggot
• root maggot
• Anthomyiidae
• brassica pest
• Integrated Pest Management
• insect-proof netting

Usage Notes

The name is often used interchangeably with 'cabbage fly,' though some specialists reserve 'cabbage fly' for the related Delia brassicae (now generally synonymized with D. radicum). Larvae are frequently called 'cabbage maggots' or 'root maggots' in agricultural literature. The term should not be confused with the cabbage whitefly (Aleyrodes proletella) or cabbage moth (Mamestra brassicae), which attack aerial plant parts.