Delia radicum

    Description

    The adult flies are approximately 6.5 mm long and are grey-brown in colour with a darker stripe along the back of the abdomen.

    Identification difficulty
    Recording advice

    This species has a red ID rating and unless identified by a known expert you must provide a satisfactory explanation of how it was identified for the record to be accepted.

    Habitat

    Gardens and cultivated fields, or in meadows and hedgerows, nectaring on flowers such as Dandelions.

    When to see it

    Found from spring and throughout the summer until September.

    Life History

    After overwintering as pupae in the soil, the flies hatch in spring, feed on nectar and lay eggs close to plants of the Cruciferae family. The eggs are white and about 1 mm in diameter. 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, turnips etc. 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. 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.

    UK Status

    Fairly frequent and widespread in Britain though poorly recorded.

    VC55 Status

    Fairly frequent in Leicestershire and Rutland.

    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

    UK Map