Biology of gall midges (a natural enemy of field crop pests)

There are 620 species of gall midges (Family: Cecidomyiidae) in the UK. Some of these are used as biocontrol in protected crops such as strawberries.

Members of the midge family can be distinguished by their broad, round, often fringed wings. They are minute to tiny (0.5–3 mm) and hard to identify.

Two to three generations per year are typical. Adults only feed on nectar or honeydew. Overwintering occurs in the soil.

The pest midge species and those that form galls are more commonly known; however, the larvae of at least five species feed on aphids, while others predate mites.

Of the aphidophagous species, each female can lay 50–150 eggs close to the aphid colony; each larva can consume up to 80 aphids.

Adults of some species are also predatory.

Unknown.

Field margins with diverse flowering shrubs and herbaceous plants provide a source of nectar for adults.

A few species are reared and released for biocontrol programmes in protected crops, strawberries and ornamentals; for example, Aphidoletes aphidimyza for aphid control and Feltiella acarisuga for spider mite control.