Pest Control: Fungus Gnats


Fungus gnats (Sciarids), which are also called dark-winged fungus gnats, are small, dark, delicate-looking flies that infest soil, potting mixes, container media and sources of organic decomposition.

Adult fungus gnats have light gray to clear wings and slender legs with segmented antennae that are longer than their head. Females lay tiny eggs in moist organic debris or potting soil.


Adult fungus gnats don’t damage plants; however, their larvae can damage roots and stunt plant growth. Significant root damage can cause plant death. Serious fungus gnat damage is more common in greenhouses and nurseries than in open fields.


There are specific natural enemies for fungus gnats. The primary beneficial insects that are natural enemies of fungus gnats are as follows.

Click the name of the beneficial insect for additional information. 

BioStratiolaelaps - (Stratiolaelaps scimitus) is a soil-dwelling predatory mite whose nymphs and adults feed on fungus gnat larva, thrips pupae and other small invertebrates. These predatory mites stay at the base of plant stems and on the soil, rarely transferring onto the plant itself.

BioAtheta - (Dalotia coriaria) is a fast-moving, soil dwelling rove beetle. A generalist predator, it feeds on a wide range of small insects and mites but is primarily an egg predator. BioAtheta is used in the control of fungus gnats, thrips pupae, shore flies, moth fly larvae, root mealybugs, springtails, and other small arthropods.

BioSf -An entomopathogenic nematode containing infective juveniles of Steinernema feltiae in an inert carrier. Nematodes invade through natural body openings and inject bacteria into the insect.