MSU Extension logo

Michigan State University Extension
Home Maintenance And Repair - 01500547
06/24/03

Nuisance Aquatic Insects, Caddisflies, Stoneflies, and Mayflies



The adults of several types of aquatic insects will frequently emerge in large numbers, causing concern among homeowners. Three types of aquatic insects frequently encountered around homes are caddisflies (Trichoptera), stoneflies (Plecoptera) and mayflies (Ephemeroptera).

Caddisflies are distinct from the other two groups by the hair-covered wings which are held roof-like over the back when at rest. Mayflies have large forewings, small hindwings that are held together at rest over the body. There are also 2 (rarely 3) caudal filaments which are equal to or greater than the length of the body. Stoneflies have a hindwing which is larger than the forewing, and the wings are held flat over the back. There are two caudal filaments, but they are generally shorter (less than half the length of the body). The adults of these insects are generally short lived, especially in the case of the mayflies, and they generally do not feed. Even though homes near aquatic habitats may be covered with resting insects during mass emergences, expensive chemical controls are seldom necessary.

The insects can be allowed to disperse naturally, or they can be removed by sweeping or vacuuming. Those insects which get indoors can be subdued with an aerosol flying insect spray containing pyrethrin, and then removed. An ordinary aerosol hair spray will also subdue flying insects by stiffening their wings and allowing their removal.

These aquatic insects are attracted to lights, and when they are active it may be necessary to reduce outside lighting or switch to yellow light bulbs. These insects are least responsive to the yellow light.

For a complete listing of suggested control options for all home, yard and garden insect pests contact your local Extension Service, found under local government in the phone book.

Read and follow instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health risk.

References

Tom Ellis, M.S., Department of Entomology.

Return to main page

This information is for educational purposes only. References to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned. This information becomes public property upon publication and may be printed verbatim with credit to MSU Extension. Reprinting cannot be used to endorse or advertise a commercial product or company.

MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

This information.was reviewed as of June 2008.  For more information about the contents please contact costner@msu.edu for webpage problems strausc@msu.edu .