The Cabbage Fly, Delia radicum, also known as the Cabbage Root Fly, is a known pest to crops[1]. The larvae of the cabbage root fly are sometimes known as the cabbage maggot. The adult flies are approximately 1 cm long and are grey in colour but otherwise resemble the common house fly.[2]
The flies can be found all over Europe.[3] After over-wintering as pupae in the soil, the flies hatch in spring, feed on nectar and lay eggs close to plants of the genusBrassica[3]. The eggs are white and about 1 milimetre in diameter.[3] They hatch into white maggots after about six days and the larvae feed for about three weeks on the roots and stems of the cabbage plants.[3] After this, the larvae are typically 0.9 to 1 cm in length and form reddish brown pupae which hatch into adult flies after around 20 days.[3] Around three generations of eggs can be laid in each year, with the generations overlapping, providing a constant presence of adult flies throughout the summer months. [3]
