Aquatic Insects: Mayflies, Caddisflies, flies, water

Certain species of aquatic insects reach tremendous numbers in population. Many molt into winged adults and some become pests in and around nearby buildings. Chemical control of these pests at their source is generally are not permissible because of environmental risks to their aquatic habitats, which are too sensitive to introduce pesticides.
The non-chemical control methods mentioned in this article will help in control of Mayflies (also known as Shadflies, Lakeflies), Caddisflies and Stoneflies, but can help in elimination or reduction in populations of many flying insect pests.

If flying insects are a problem when large numbers fly into warehouses or other such building,
professional fly zappers can sometimes be used to reduce numbers trying to enter buildings.

Mayflies, caddisflies and stoneflies may become pests when they swarm to lights around homes, restaurants, marinas, outdoor swimming pools, campgrounds, RV areas or any brightly lit sites.
Four factors determine the number of insects flying to a particular light.

Brightness: A 100-watt bulb will attract more insects than a 75-watt bulb.

Ultraviolet Output (UV): Different lights put out different amounts of UV light; mercury-vapor lamps and fluorescent lights have high UV outputs and are very attractive to insects.

Heat Output (infrared energy): High-powered incandescent lights put out a lot of heat. This attracts certain insects.

Competition: If the only light in the neighborhood is over a loading dock door, insects in the area will zero in on that light.

Non-Chemical Control Summary: The following recommendations for outdoor lighting can make a difference in certain flying pest populations.

Replace incandescent floodlights or standard bulbs with dichrom yellow lights.

Install UV output of bulbs with refractors or filters.

Install decoy lights to draw insects away from the building. One recommendation (from the National Pest Control Association) is to use 100-watt, clear mercury-vapo lamps, spaced 100 feet apart and set 200 feet from the building to be protected.

Chemical Control Measures
If caddisflies or stoneflies rest on the sides of buildings in great numbers, a surface spray such as Cynoff WP can be used for a quick knock-down and 1 to 4 weeks limited residual or long term control. This treatment is sometimes necessary for commercial buildings (drive-in restaurants, etc.) which have a great deal of exterior lighting which attracts flying insect pests. Flying pests can be unappealing for customers in these cases.