Sciarid flies
Description
Also known as fungus gnats, these are greyish brown flies about 3-4mm long. The adults do not harm plants, but can be very annoying they fly around when disturbed.
Symptoms
The young are slender white maggots with black heads, about 6mm long, which live in the compost. They feed mainly on dead, decaying plant material and on soft plant growth, such as seedling roots and the base of soft cuttings.
