Close up of a fungus gnat landed on a perch with a purple background.

fungus gnat

Lay up to 300 eggs in batches of 2-30

INFESTATION SIGNS: wilting, yellowing, poor growth and foliage loss

Adults live for up to 7-10 days and repeatedly reproduce

Found either on the plant or within the soil, fungus gnats fly up whenever plants are disturbed. Measuring about an eighth-inch long, adult fungus gnats are slender, dark-colored, mosquito-like flies with long legs, antennae and one pair of wings. Larvae or maggot fungus gnats cause the most plant damage. These transparent-white larvae, which have black heads, not only feed on fungi and decaying organic matter, but also on living plant tissue - predominantly root hairs and small feeder roots. Brown scars often appear on chewed roots. In sufficient numbers, larvae can severely weaken and kill plants. Several symptoms of fungus gnat infestation include wilting, yellowing, poor growth and foliage loss.

Primarily infesting potted plants, fungus gnats cause the most damage during the early stages of plant development. They continuously reproduce in greenhouses where warm temperatures are maintained. Adults live for 7 to 10 days and deposit eggs on soil surfaces or in soil cracks. Females lay up to 300 eggs in batches of 2 to 30. Barely visible to the naked eye, the eggs are shiny-white and semi-transparent.

Enstar® AQ product controls larval stages of fungus gnats, eliminating damage and preventing reinfestation. The Enstar® AQ product fungus gnat program for light to moderate infestations involves applying one 16-ounce bottle of Enstar® AQ product per 100 gallons of water as a drench. To control heavy infestations, two 16-ounce bottles of Enstar® AQ product per 100 gallons of water. Make 2 applications 7 to 10 days apart.

For the best fungus gnat larval control, add 5 teaspoons of Enstar® AQ product to 5 gallons of water (per 1000ft2) and apply the product as a drench to soil. The adult gnats will not die because they live out the current stage of their life cycle. Enstar® AQ product prevents the larvae from becoming adults thereby eliminating future generating.

To control adults, Mavrik Aquaflow® insecticide may be applied to foliage at the lower rate.