Sonic mosquito repellers, first marketed in the 1970s, are devices that were designed to imitate the flight sound of a male mosquito. These devices work on the assumption that a mated female mosquito would avoid further contact with males. Other similar devices supposedly imitate the flight sounds of dragonflies. When tested in the laboratory and field these repellers have shown NO repellency of mosquitoes.
Ultrasonic mosquito repellers are devices that are supposed to mimic the sounds made by bats, which are known to be important mosquito predators. These devices have been tested in controlled experiments and were found to be INEFFECTIVE in reducing mosquito-biting rates. While some insects avoid bats, mosquitoes do not.
Find more information about pests in eXtensions Pest Management In and Around Structures Resource Area.