Fungus Gnats

• Fungus gnats look very much like mosquitoes and can be found flying near plants, according to the University of California. Adult fungus gnats cause little damage to the plant itself. But their larvae, live off of your plant's roots. Because female gnats can lay up to 120 eggs, your fungus gnat larvae problem can skyrocket within weeks. Problems are at their worst during the winter and spring months, according to Colorado State University. It is extremely important to recognize fungus gnat damage before your pest problem seriously harms your plants.
  
  

Damage

• Fungus gnat larvae damage root systems, which causes stunted growth. Gardeners may notice their plants stop growing during the growing season. Also, the wounds they leave in the roots raises the risk of the plant contracting diseases such as root rot. Larvae are also particularly damaging to the roots of seedlings or young plants, according to the University of Florida. Young seedlings are not mature enough to tolerate wounds made into their roots.
  
  

Insecticide

• Spraying adult fungus gnats will not quickly remedy you problem, because it is likely that they have already laid their eggs in the soil. Biological insecticide that contains bacillus thuringiensis var. israelensis effectively controls fungus larvae, according to Colorado State University. Bacillus thuringiensis var. israelensis kills larvae by infecting them with a bacterial pathogen. This insecticide type is used as a soil drench. Apply the soil drench to the potting medium according to the directions.
  
  

Cultural Control

• Avoid over watering your plants. Standing water attracts fungus gnats. When watering potted plants, apply water until it drains from the draining holes at the bottom of the container. Allow the surface of the potting soil or soil in your garden to dry out before the next watering. Remove their favorite breeding areas from around your plants such as mulch, grass clippings and compost, as suggested by the University of California. Rake up any leaves laying around ornamental plants, especially if they have fungus gnat problems.