Aquatic Midges, also known as “Blind Mosquitoes”
Blind mosquitoes are a type of freshwater midge. This particular type of midge does not bite, suck blood, or carry diseases. However, blind mosquitoes can still be a nuisance and their populations are often extremely difficult to manage. Read on to learn more about blind mosquitoes and the most effective ways to control their numbers.
Blind mosquitoes are one of the most common organisms in both natural and artificial water systems. There are four stages in their life cycle: egg, larva, pupa, and adult. Part of midges’ life cycle is aquatic, and part is terrestrial. Large populations of freshwater midges are often indicative of a system that is abundant in nutrients and contains high counts of algae. When midges emerge from their habitat, they come off in swarms, which can be a nuisance. You can find midge larvae in numerous systems such as:
- Small and large natural lakes
- Wastewater channels
- Sewage oxidation and settling ponds
- Residential and recreational lakes
Why They Are Problematic
According to P.G. Kohler, over the past 20-30 years, blind mosquitoes have become more of a nuisance due to:
- New midge-producing habitats constructed near residences
- Deteriorating water quality which helps midge populations thrive
- Increasing desire of homeowners to live close to lakes and rivers
Between April and November when midge populations are highest blind mosquitoes can be an extreme nuisance, especially to residents living in breeding areas. Midges prefer cool, shady areas during the day and are attracted to the lights surrounding houses and businesses at night. When the population of blind mosquitoes is high, they often cause home and business owners grief by staining paint, stucco, and other wall finishes. They can also damage the headlights, windshield, and paint of automobiles due to their bodies becoming mashed onto the car from driving. Blind mosquitoes will fly inside of residences and cause indoor issues such as ruined laundry and stained indoor walls, ceilings, draperies, and other furnishings.
Spiders are natural predators of midges. Dead midges and spider webs force residents and business owners to frequently wash and maintain their homes and businesses. This is because dead midges have a similar smell to rotting fish as they decay.
Controlling Freshwater Midge Populations
It is impossible to completely control blind mosquitoes and partial control is often too expensive or too complicated to be practical. The use of insecticides on adult midges is only a short-term fix and can even be counter-productive if it also kills the natural predators of midges such as spiders.
Blind mosquitoes can be more populous in polluted water. Waste from food-processing plants, septic tanks, sewage treatment plants, and leaching of fertilizers from lawns and agriculture around lakes provide the nutrients needed to produce the food that allows freshwater midges to thrive. As pollution continues to increase, so do blind mosquito populations.
University of Florida IFAS researchers (UF/IFAS) has developed a Freshwater Aquatic Midge Integrated Pest Management Plan to aid in controlling the blind mosquito problem in stormwater ponds and man-made stormwater lakes.
The plan to help reduce the population of these pests has four steps:
- Controlling algae count by treating private or man-made ponds with algaecides
- Using insectivorous fish to biologically control blind mosquito populations
- Implementing light traps to trap and kill midges
- Using insect growth regulators (IGRs) to prevent larvae from developing into the adult stage, in private or man-made ponds
If your freshwater midge issue involves one of Polk County’s natural lakes, please note that Step #3 is the only part of this plan which can be used by residents. Residents are not allowed to use any chemical treatments in natural freshwater lakes without an approved permit from Florida Fish and Wildlife Conservation Commission. Please see below for additional recommendations.
Recommendations for the Waterfront Resident
Because light attracts blind mosquitos, reducing the use of unnecessary home lighting at night will help prevent blind mosquitoes.
A “light trap” can be used in an unoccupied corner of the yard to attract blind mosquitos away from the home. This can be accomplished using any bright light. The best way to trap the midges is to shine the light on a lightly colored wall or surface, such as a white fence. The light should come on at dusk and stay on an hour past sunset.
For the best results:
- Convert all outdoor lighting that shines on the house (like porch lights) to motion-activated lights and keep the brightness lower than the light trap (if in use). Motion activated lighting should reduce the attractiveness of your home to the midges, who tend to gather near lighted areas.
- Prevent additional nutrients being added to ponds and lakes by reducing fertilizer use in the landscape, creating a 10-foot no-maintenance zone (also known as a buffer strip) of un-mown, un-fertilized landscaping, and keeping grass clippings out of the water. Learn more, by reading about Florida-Friendly Landscaping, here: https://ffl.ifas.ufl.edu/ffl/protecting-waterfront.html
More Recommendations, by water type
For natural lakefronts and areas where planting is allowed: consider planting aquatic plants that improve the waterfront such as pickerelweed, soft rush, duck potato and others. Aquatic plants can help remove excess nutrients that midge larvae feed on from the submerged sediments in which they live. This process, although slow, will also help to improve overall lake health and wildlife habitat.
For pond owners: consider stocking your pond with insectivorous (insect-eating) fish and bottom-feeding fish, such as catfish. These types of fish will help control midge populations by feeding on their larvae that live in pond sediments and the water column.
For decorative ponds, the University of Florida/Institute of Food and Agricultural Sciences (UF/IFAS) has compiled a list of freshwater fish recommended for midge control.
For more information on freshwater midge population control, please visit UF/IFAS EDIS’ document:
This blog post was written by Natural Resources Extension Program Intern, Ms. Paxton Evans, under supervision by Natural Resources and Conservation Extension Agent, Mrs. Shannon Carnevale.
If you have a question that is not answered here or in the existing comment section, please contact your local extension office for more information. If you live in Polk County, please send Mrs. Carnevale an email with your additional questions: firstname.lastname@example.org