Mosquitoes are by far one of the most difficult insects to control. Large populations, rapid reproduction, and the wide variety of species and habitat requirements are just a few of the issues we face.
One of the most important aspects of control is understanding how pesticides work to repel these disease-harboring insects. If you offer mosquito services, it’s very likely you’ve heard the question, “If you sprayed a repellent insecticide in my yard, why do we still see mosquitoes?” The answer lies in the word repellent. What the industry now generally refers to as repellent insecticides are not true repellents; they are instead classified as excitorepellents.
True repellents are chemicals that prevent insect damage to plants or animals by rendering them unattractive, unpalatable or offensive. Insects detect vapor produced by true repellents without physical contact, and it is this vapor that drives insects away from the source. An example of true repellents are essential oil pesticides. Insects detect them in the vapor phase and make oriented movements away from the source.
By contrast, excitorepellents affect insects only after their tarsi or other body parts contact treated surfaces and then accumulate enough of the pesticide residual from the surface to result in neurological disturbances and death. In other words, mosquitoes must come into the treated zone and touch plants or areas that have been treated for excitorepellents to be effective.
As a final note, when you’re performing a mosquito service, you can help protect our pollinators by remembering that weeds have flowers, too.