Another common cause of infestations is bringing outdoor plants indoors . If you want to test a plant for fungus gnats before bringing it inside , you can use a potato slice to detect them . Insert ¼-inch slices into your growing medium and then turn them over to check for gnats after a few days . Fungus gnat larvae will be attracted to the potato to feed on it if they are present in the medium . If you adjust your watering practices and your infestation still doesn ’ t clear up after several weeks , it may be time to use an insecticide . If your fungus gnat population is large , you may need multiple applications to clear up the problem .
“ In order to control these pests , it is necessary to understand what causes infestations .”
How to Control Fungus Gnats
Pyrethroid-based insecticides that contain bifenthrin , cyfluthrin , permethrin , and lambda cyhalothrin are effective against fungus gnats . They work by disrupting their nervous systems and subsequently cause paralysis and death . Although generally safe if used properly , pyrethroids have been known to cause some damage to humans and the environment . If you decide to use these chemicals , make sure you follow the directions closely and take all necessary precautions to minimize these risks . This may include wearing protective gear like gloves and goggles , choosing pesticides with lower toxicity levels , using the correct dosage , staying out of the treated area for the required time listed on the label , and ventilating indoor areas . Bacillus thuringiensis var . Israelensis ( Bti ) is a bacterium found in soils that is commonly used as a pesticide by growers . Pesticides that contain this active ingredient can be used as a soil drench to kill fungus gnat larvae . It works by excreting toxic chemicals once it has been ingested by a pest , and is generally safe for humans . Apply Bti every three to seven days to control the population . Neem oil is a natural extract from the seeds of the neem tree that has a wide variety of uses , from beauty products to pesticides . It is one of the safer products to use for pest control in your garden and will not harm pollinators , although you will probably need multiple applications to eradicate your problem . It can be used as a soil drench for larvae , and as a spray to repel adult gnats . When choosing your neem oil product , be sure to choose a cold-pressed neem oil , which is less processed than clarified hydrophobic neem oil . Cold-pressed neem oil is the most natural and complete form of neem oil and still contains azadirachtin , which is a key ingredient to fighting pests . Azadirachtin acts as a poison to insects when they ingest it . It is also a growth regulator and prevents insects from transitioning into their next stage of development and laying eggs . Yellow sticky cards are helpful when controlling adult fungus gnat populations . They are attracted to the yellow color and will land on the card . Place the sticky cards under the canopy at the edge of your container . By trapping adult females , you ’ ll prevent them from laying their eggs and reduce their population . You can also add beneficial nematodes , such as Steinernema feltiae , or predatory mites to your garden to feed on the fungus gnats . These biological controls are most effective in the beginning of the growth cycle at planting , before fungus gnat populations get out of control . You ’ ll want to apply them two or three times , about a week apart . Predatory mites will last about six to eight weeks . Beneficial nematodes reproduce and can potentially last through harvest if their population is established early on .
Fungus gnats are annoying , but relatively easy to manage and control if you understand them . If you make sure not to overwater and use a few simple controls , you can keep them from calling your garden home .
72 Maximum Yield