Buckeye Yard and Garden onLine

Adult fungus gnats are about 1/8" to 1/10" (2.5 mm) long, grayish to black, slender, mosquito-like, and delicate with long legs, antennae and one pair of wings.  Identification can be made by the vein patterns in the wings.  Darkwinged fungus gnat adults have eyes that meet above the base of the antennae.  Eggs are hardly visible, oval, smooth, shiny white and semi-transparent. Larvae or maggots are legless, thread-like, white, shiny blackheaded, up to 1/4" (5.5 mm) long and transparent so food in the gut can be seen through the body wall.  Pupae occur in silk-like cocoons in the soil.

The fungus gnat is sometimes confused with another small dark-bodied fly called the shore fly.   Shore flies have more robust bodies than fungus gnats and their antennae are very short.  Their most distinguishing characteristic is the presence of five light-colored spots on each of their dark wings.  Shore flies are also stronger, faster fliers than fungus gnats.  In the larval stage shore flies can be distinguished by the opaque, tannish-brown color of the body and the absence of a head capsule.

Several insecticides are available to the commercial growers that will provide good control of these pests.  Chlorfenapyr (e.g. Pylon) is very effective in greenhouses.  Pyriproxyfen (e.g. Distance) is good outdoors.  Neonicotinoids also provide good chemical control.  For further information on this insect, including chemical controls, please refer to NCSU: ENT/ort-29, "Darkwinged Fungus Gnats"  below.

For more information, see: 

• Darkwinged Fungus Gnats