December Pest of the Month: Fungus gnats

Tuesday, 8 December 2020

Fungus gnat larva. Note the distinctive black head capsule.

Name: Fungus gnats – Bradysia spp.

Larvae feed on organic matter and roots, stripping root hairs especially of seedlings and young plants. Tunnel into stems at and below the soil line causing collapse of tissue. Larvae can ingest fungal spores such as Pythium and Fusarium and spread them in both the larval and adult stages. Adults can spread foliar diseases like Botrytis.

Egg: Very small, laid in cracks and crevices of soil surface. Immatures: White, semi-transparent and maggot-like, with distinctive black head. Pupates in soil or potting media. Adult: Small, slender black or dark brown fly with long dangling legs and long antennae. Often found running over soil surface or leaves, weak fliers. Y-shaped vein at tip of wing.

For further information, please refer to the Pest ID Tool at: