Fungus gnats (Diptera: Tephritidae) are common pests of flowers, crops, and trees in many parts of the world. They are among the most common insects found on plants. The most common species are the European red mite (Panonychus ulmi), the American red mite (Panonychus citri), and the Asian citrus psyllid (Diaphorina citri).
These three species are considered to be the most important insect pests of citrus fruit. All species of fungus gnats are blood-sucking parasites of living plants. Females lay their eggs in the soil or on decaying organic matter near plant roots, and larvae emerge as adults in two to four weeks. Adults feed on a variety of plants, including trees, fruit, and vegetables. They can be difficult to control because they are often very abundant in infested areas and will breed rapidly under favorable conditions. A wide range of pesticides may be used to control these pests. Commonly used products include insecticides such as organophosphates, carbamates, pyrethroids, and chlorinated hydrocarbons.