How to Get Rid of Gnats Outside

Biting and Non-Biting Gnats

There is some disagreement surrounding what small flies should be referred to as gnats. To help clarify this issue, we will consider the most common indoors gnats to be non-biters and the most common outdoor gnats to the biting gnats. These biting gnats are not only nuisances, but create extreme discomfort and may cause medically-related problems because of their biting behaviors.

image of a gnat

Outside Control of Non-Biting Gnats

Usually, control of non-biting gnats involves the complete elimination of their developmental sites. The most common gnats in this group are fruit flies, fungus gnats, phorid flies and moth flies.

Eye Gnat Control - A non-biting gnat that is rarely a problem inside, but is a very troublesome nuisance gnat outdoors, is the eye gnat. Eye gnats are attracted to the moisture of the eyes and nose and are especially annoying in the spring and fall, but in some areas are year-round problems.

Female eye gnats lay their eggs in or on soils that are moist and contain organic matter. Generally eye gnats populations are something one may have to simply put up with since there are few, effective ways to even temporarily control them using insecticides or habitat elimination.

Outdoor control of the non-biting group of gnats is often needed since outside breeding and developmental sources are producing large populations of gnats that may eventually get inside our homes and businesses. Therefore, the reduction or elimination of their exterior developmental sites is very important and may include:

  • Dry Out Moist Areas - Eliminating moist outdoor sites that are rich in organic matter. Examples include outdoor potted plants, clogged roof gutters and downspouts, sites near downspouts that remain moist for extended periods, near air conditioners where condensation is allowed to pool or improperly drain, thick mulch, compost piles, accumulated piles of grass clippings, leaves and garden debris.
  • Fix Leaky Pipes - Repairing and eliminating exterior sites where plumbing leaks allow sewage or water to accumulate. This often is a serious problem when leaking plumbing allows the deposition of sewage and fresh water to accumulate on the soil in the home or other building’s crawlspace.
  • Sewer Maintenance - Properly maintaining sewage treatment facilities to ensure that moth flies do not become a nuisance to surrounding homes or buildings.
  • Clean Up - Not allowing fallen fruit to accumulate on the ground since fallen fruit is an ideal outside developmental source for fruit flies and is also likely to attract yellow jackets that feed on the fruit.
  • Exterior Lighting - Replacing standard exterior light bulbs with low voltage, bug light bulbs that are less attractive to flying insects.
  • Eliminate Moist Soil - Avoiding overwatering of outside plants and lawns.
  • Cover Garbage - Always keeping garbage cans and other trash containers clean and covered.

Biting Gnat Control

Gnats included in this group are those that are frequent nuisances and bite people and animals to consume blood. Biting gnats can cause medically related problems such as allergic reactions to their bites.

The more common biting gnats include biting midges also known as no-see-ums, punkies, sand flies, plus black flies that are also called buffalo gnats. There are many other biting flies such as horse flies, stable flies and deer flies, but those flies are not generally considered to be small flies and thus do not fit into the group of flies called gnats.

Biting midges affecting people generally develop and live in moist habitats, coastal marshes springtime pools of water and freshwater inlets along the coastal regions. Black flies usually develop in flowing streams and rivers with waters containing high oxygen content and have flight ranges up to several miles from their developmental sites to where they take a blood meal.

These habitats are generally large, variable and provide little access to anyone other than private or government mosquito abatement and control organizations. Therefore, biting midge and black fly control is very challenging, only marginally effective, and quite expensive for individual homeowners. However, there are a few things that can help prevent and control of biting midges. Some include:

  • Planning of Outdoor Activities - One of the more important ways to avoid or at least reduce the impact of these biting flies is to schedule outdoor activities when they are least likely to be a problem. For example, biting midges are the most active during the evening hours when there is very little or no wind. Being indoors or inside screened areas outdoors can aid in avoidance and protection from bites. Biting gnats are so small that standard window screening allows them to get inside, so using smaller sized mesh screens, sometimes called biting midge screening, is required.
  • Cover Up - Wearing Long Sleeves, Head Nets and Long Pants to reduce bodily exposure to biting gnats is helpful.
  • Repellents - Using insect repellents approved for biting gnat prevention is only marginally effective and usually is nowhere near as successful as when used to repel mosquitoes.
  • Fans - Since biting gnats are small, weak fliers, using ceiling and other fans are effective at keeping biting gnats away.
  • Small Scale Area Use of Insecticide Sprays -Using aerosol insecticide sprays have limited effectiveness even when properly used; therefore, the benefit of using this method for control may not be worth the effort. Before attempting the use of insecticides, ensure the product is approved for use against biting gnats and flies, plus closely adhere to the use instructions described on the product label.