Fungus gnats can infest indoor or outdoor plants. The adult fungus gnat looks much like a small mosquito and can be seen flying close to infected plants. While adult gnats do no damage to plants, their larvae damages plant roots. Adult gnats lay hundreds of eggs in rich, organic soil. The eggs then hatch into larvae. Fortunately, the adult fungus gnat does not bite humans or carry harmful pathogens, according to the Agriculture and Natural Resources Department of the University of California.
Remove dead and fallen leaves from the soil around the infected plant. Look to see if any fungus gnat larvae are present. The larvae are white maggots with black heads.
Allow the soil in the plant to dry out as much as possible without harming the plant. The larvae needs damp soil to survive. The larvae will die in dry soil.
Lay down sticky tape traps near the plant to catch adult gnats. Monitoring the amount of adults on the paper will also show you if the infestation is improving.
Spray the area surrounding the plant with a pesticide. The pesticide should be labeled for flying insect control. Follow the manufacturer's instruction to see if the pesticide is safe to spray directly on the plant.