Midge Fly Fact Sheet
Midge flies are a food source for other aquatic insects, such as dragon fly nymphs and several varieties of fish, so the goal is not to completely eliminate them, but to keep them in proper balance within the ecosystem. Midge fly populations grow exponentially in water that is high in nutrients and bottom muck, and low in oxygen, environments that don’t support fish.
- Swarms tend to be worse in the spring and early fall
- At night they are attracted to lights around houses and businesses
- Outdoor activity can be difficult as swarming midges can be inhaled
into the mouth and nose and get into eyes and ears
- Swarms fly to cool shady areas & stain paint, stucco, roofs, cars, etc.
- Small & large pond and lakes, whether natural or man-made
- Larvae live on and in the lake bottom making them more difficult to
control and to detect imminent adult swarming
What can be done about them?
Shorter term control with fast results includes applying larvacides to the lake to prevent midge flies from developing into flying adults.
For longer term control, you need to improve the lakes water quality. As lakes age many develop layers of organic bottom muck that dramatically lowers dissolved oxygen levels favoring growth of midge fly larvae while preventing fish and other insect predators from feeding on them. Infested lakes can easily support populations of 2,000 larvae/square meter.
Lakes low in oxygen and high in nutrients, pollution and algae are a perfect habitat for midges. The most effective long term remedy for midge flies may be installing a Vertex diffused air aeration system to raise oxygen levels and improve overall water quality.