Do Fungus Gnats Kill Plants?

Tiny and delicate, adult fungus gnats can be a nuisance when they infest one of your plants. The adults do not bite and are not harmful. When the gnats are in the larval stage, however, they can be a harmful threat to your plants.

Damage

Fungus gnats are a threat to plants when they are in the larval stage. While developing in moist soils, larvae feed on plant roots. If there are sufficient numbers of larvae feeding on roots, they can damage or kill a plant.

Control

Fungus gnats can be killed using chemical controls. Insecticides like pyrethrin sprays will kill eliminate the gnats, according to Ohio State University. You can use diazinon, another insecticide, to target the larvae directly to stop them from doing further damage to the plant's roots.

Prevention

You can prevent fungus gnats from damaging and killing plants by preventing them from infesting soil. Always inspect new soil to be sure it is larvae free. Avoid over watering plants, because they thrive in wet soil, according to Texas A&M University.

References

• Texas A&M University: Fungus Gnats
• Ohio State University: Fungus Gnats