Insect Identification

Fungus Gnats

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® II controls all stages of fungus gnats, eliminating damage and preventing reinfestation. The Enstar® II fungus gnat program for light to moderate infestations involves applying one 5-ounce bottle of Enstar® II per 100 gallons of water two to three times every seven days. To control heavy infestations, two 5-ounce bottles of Enstar® II per 100 gallons of water should be applied two to three times every seven days.

For the best fungus gnat larval and adult control, add 3 teaspoons of Enstar® II to 5 gallons of water and spray 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® II prevents the larvae from becoming adult thereby eliminating future generating.

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