Darkwinged Fungus Gnats, Bradysia spp., In Florida Greenhouses

Most species of darkwinged fungus gnats (Sciaridae) feed on fungi and decaying organic matter and are not considered economic problems. A few species, however, attack healthy tissue of such economic plants as potatoes, wheat, red clover, alfalfa, cultivated mushrooms, pine seedlings, and various ornamentals, including tulip bulbs, ferns, begonias, coleus, geraniums, cacti, young orchids, areca palm, and dracaenas. In recent years there has been an increasing number of complaints about sciarids being a problem in Florida greenhouses, mostly concerning injury to plants but also large numbers of flying gnats being an occasional nuisance to workers. Some growers have had difficulty achieving adequate control of these fungus gnats, and more information is needed on effective insecticides, dosage rates, methods of application, and possible phytotoxicity.