Scientific Name:Diptera
Length:1mm - 13mm
Spreads Disease?No
Risk Factors: Swelling, spreading of parasites, damage to plants

How to get rid of this?

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What Do Gnats Look Like?

Most gnats are much smaller than other large species of flies. A gnat’s body is divided into three parts: The head, thorax, and abdomen. They have two large antennae on their small head and a pair of large wings. Gnats can appear in various colours, such as black, brown, grey, and sometimes even yellow. 

Fungus gnats look a bit differently than the usual gnat; they have distinctly elongated coxae that connect their legs to their thorax. 

Habitat, Diet, and Lifecycle 


Gnats can be found all over the world, but they mostly frequent greenhouses, sod farms, and nurseries. Some species of gnats prefer to be near overwatered/fungi-ridden plants to mate and feed. Other gnat species stay close to places with running water, such as rivers and streams with fast-flowing streams.


The diet of gnats can vary, depending on the species and gender. For example, female gnats prefer to feed on blood from humans, pets, and livestock, while male gnats feed on nectar. 

Fungus gnats feed on various plants, but their larvae feed on the fungi that grow on overwatered vegetation or decaying organic matter. 


Gnats hatch from eggs as larvae, develop into pupae, and emerge as adults. Female gnats can lay up to 500 eggs in their lifetime. However, the presence of moisture helps the offspring mature into adults. For example, most gnats will lay their eggs in rivers or streams by attaching them to nearby vegetation or rocks.

Once the larvae emerge, they also attach themselves to vegetation and rocks. From there, they filter-feed on the vegetation in the water until they reach pupation. The pupation process occurs underwater in silk cocoons where the adults eventually emerge in air bubbles. 

In addition, fungus gnat eggs and larvae mature in moist soil. Many people may notice plant damage before a swarm of gnats appear. Why? It’s due to the developing larvae feeding on organic mulch, leaf mould, grass clippings, compost, roots, and fungi.  

Why Do I Have Gnats?

With over 600 species of gnats in North America, the most common are fungus gnats and dark-winged fungus gnats. These insects often frequent buildings with overwatered, fungi-ridden plants, making greenhouses and sod farms some of the most typical places for gnats to reside. Gnats remain present as long as fungi on overwatered vegetation and decaying organic matter are accessible.  

How Worried Should I Be About Gnats?

Female gnats bite humans, mammals, and other animals to get their blood meal. While the bite won’t transmit diseases, it can cause severe swelling. 

Some species have been known to transmit parasitic nematodes, which can cause onchocerciasis or river blindness. An overabundance of fungus gnats can cause significant damage to potted, ornamental, or greenhouse plants. Crops of vegetation can suffer if larvae attack the fungi. 

How Can I Prevent Gants?

The best way to avoid gnats is to do the following:

  • Avoid overwatering plants. 
  • Ensure proper drainage and aeration. 
  • Remove any standing water or infested soil/vegetation. 
  • Seal cracks in foundations. 
  • Fix broken doors and windows.

Contact Gilles Lambert Pest Control to get rid of your gnat problems.