Midges are tiny, flying insects often mistaken for gnats or mosquitoes. They quickly become a significant nuisance due to their sheer numbers, emerging from moist environments in massive swarms and disrupting outdoor activities. Biting species, often called “no-see-ums,” cause itchy, painful welts. Non-biting types are primarily an annoyance, frequently attracted to light sources after sunset. Controlling a midge problem requires a multi-pronged strategy focused on eliminating breeding sites, using physical barriers, and applying targeted chemical treatments.
Removing the Source of Infestation
The most effective long-term approach to controlling midges is eliminating the aquatic or moist environments where they lay eggs. Midge larvae, sometimes called “bloodworms,” thrive in standing water, moist soil, and water bodies rich in decaying organic matter. Larval densities in nutrient-rich water can exceed 4,000 per square foot, emphasizing the importance of source reduction.
Homeowners should inspect their property for sources of stagnant water, including clogged gutters, unmaintained birdbaths, or potted plant trays. Managing moist soil around the foundation is also necessary, as this supports the larval development of certain midge species. Trimming back excessive vegetation and organic debris near water features or structures can help reduce adult resting sites.
For larger water sources that cannot be drained, such as retention ponds or ornamental lakes, biological controls are an effective and target-specific solution. Bacillus thuringiensis israelensis (Bti) is a naturally occurring bacterium that produces protein crystals toxic only to the larvae of midges, mosquitoes, and black flies when ingested. Bti is typically applied directly to the water, killing the larvae before they mature into swarming adults.
Physical Barriers and Exclusion Techniques
Once the breeding source is addressed, physical barriers prevent adult midges from entering living spaces. Standard window screens (typically 18×16 mesh count) are often insufficient to block the smallest midges, frequently called “no-see-ums.” To effectively exclude these tiny insects, a tighter mesh, such as a 20×20 count, is required and often marketed as “No-See-Um” screening.
Securing all windows and doors with this finer mesh is the first step, along with patching any tears or gaps in existing screens. For outdoor areas like porches or decks, high-speed oscillating fans offer an immediate, non-chemical defense. Midges are weak flyers and struggle to navigate air currents exceeding 5 miles per hour. The directional airflow physically prevents them from landing and disperses the plumes of carbon dioxide and body heat that attract them to humans.
Non-toxic sticky traps can be used as a supplementary tool, though they are generally more effective for monitoring or localized control than for managing a large infestation. Yellow sticky traps placed near entry points can capture individual midges attempting to enter the home. When spending time outdoors, wearing light-colored clothing with long sleeves and pants can reduce the exposed skin available to biting species.
Repellent and Insecticide Treatments
For immediate relief from high populations of adult midges, targeted chemical treatments provide a fast knockdown. Personal repellents contain active ingredients that interfere with a midge’s ability to locate a host. Repellents containing DEET (N,N-diethyl-m-toluamide) or Picaridin are considered highly effective against biting flies, with concentrations between 10% and 30% DEET providing protection for several hours.
Picaridin is often favored because it is less likely to damage plastics and synthetic materials than DEET. Oil of Lemon Eucalyptus (OLE) also offers a plant-based alternative with comparable protection to low-concentration DEET products. When applying any repellent, limit it to exposed skin and clothing, avoiding application beneath clothing where skin absorption is increased.
Area treatments utilize insecticides to immediately kill adult swarms or leave a lasting residue on surfaces. Thermal foggers, which generate a dense mist of insecticide, offer a rapid knockdown of adult midges, clearing the air in a localized area. For a longer-lasting effect, residual insecticides containing pyrethroids like Bifenthrin or Deltamethrin can be applied to vegetation, building exteriors, and other resting surfaces. Midges landing on the treated surfaces pick up a lethal dose, with the residual effect lasting for several weeks.