Encouraging long-legged flies as a biocontrol for field crop pests

There are 287 species of long-legged flies (Family: Dolichopodidae) in the UK, of which, six are important for biocontrol.

Adults are small, 1–9 mm long, with long slender legs. They tend to have metallic green bodies, although they can be yellow, brown or black. The wings are opaque or with dark areas towards the tips.

Larvae develop in the soil, on dead organic matter or in crevices on trees and are predatory or are leaf-miners. The number of generations per year is unknown. The adults are strong flyers.

Larvae may predate small, soil-inhabiting insect pests. Adults are very common in field margins and crops, predating small invertebrates, including pest aphids, midges, thrips and other fly larvae or adults, or only feed on floral resources. Six species are important for biocontrol.

Unknown.

Techniques to encourage long-legged flies include:

• Providing field margins with diverse flowering shrubs and herbaceous plants
• Avoiding cutting in the summer
• Preventing pesticide drift into margins