Description
There are over 50 species of sciarid fly in Aotearoa New Zealand. They are small, dark coloured, mosquito-like insects. Adults grow between 2 and 3 millimetres long and can be seen flying around plants during watering or crawling on the soil surface. Their larvae are tiny transparent maggots about 3 to 5 millimetres long with black heads. Larvae live in damp soil or growing media rich in organic matter. They are usually found within the top 50 millimetres of soil or growing media. Larvae can cause significant damage by chewing the roots of seedlings and containerised plants.
Common native plant hosts
Broad range of native plant hosts.
Symptoms and damage
- Larvae transmit soil borne fungal diseases which can cause damping off in seedlings.
- Larvae tunnel into the roots or stems of seedlings causing them to collapse.
- Leaf yellowing.
- Plants can collapse from soil level.
- Plants lack vigour.
- Presence of large numbers of small mosquito-like insects.
- Small brown scars on roots, root hairs eaten off.
- Weak or dead plants
Prevention and control tips
- Avoid overwatering and waterlogging.
- Biological control organisms.
- Chemical insecticides.
- Commercially available predatory mites and nematodes.
- Use sterile growing media.
- Yellow sticky traps to monitor the adult population.