By Bev Johnson

Master Gardener

Have you gotten a colorful flier from a pest company promising to make your yard mosquito free? Sounds wonderful, doesn’t it? “Make outside fun again, and the only good mosquito is a dead mosquito,” “Kids love butterflies but not ticks,” and “Battle back to protect your kids and pets.” 

They claim that their spray only kills mosquitoes; they lie! They typically spray pyrethroids, a broad-spectrum insecticide applied at levels that not only kill mosquitos but also bees and butterfly caterpillars, according to a soon to be published study by the Xerces Society for Invertebrate Conservation. In some cases, the contamination levels of sprayed yards were higher than the known thresholds for killing honeybees, according to Aaron Anderson, a pesticide program specialist. 

Yard treatments affect fireflies, and many other insects that roost, nest, and eat vegetation targeted by sprayers. Because some of their formulations are long-lasting, they may continue to affect insects that come in contact with it for days or even weeks. Anderson cites an example of a leaf cutter bee lining her nest with pieces of leaves before laying her eggs and adding pollen. If those leaves have been sprayed with pyrethroid, the bee is exposed—along with the egg and the developing larvae are also exposed. Pollen and nectar may also be contaminated. 

What happens to a hummingbird who drinks the nectar? Can’t be good. 

“Mosquito spraying propaganda follows a well-worn playbook of false product marketing. 1. Name a target. 2. Spread myths about that target. 3.Invoke ‘guilt by association’ about other misunderstood targets (usually ants and spiders) and 4. Promise a paradisiacal existence once the targets are eliminated.” Ecologists say this reveals a basic misunderstanding of mosquito ecology. We know about the disease carrying species such as the genus Calex but there are over 100 genera of mosquitoes. Most of the world’s 3,500 mosquito species don’t even bite people, and believe it or not, some are even pollinators and some are prey. There are 200 species now in the U.S. and our territories. Only 12 carry pathogens. Spraying all adult mosquitoes can leave us with a few that will develop resistance to the poisons. 

According to Adrian Caper, a senior ecologist for the city of Boulder Colorado’s Climate Initiatives Department, “when multiple species are competing for food, egg laying sites and hosts, a healthy diverse thriving mosquito community is actually a defense against any one species – like West Nile virus vectoring mosquitoes becoming overly abundant.” It operates one of the nation’s most innovative mosquito management programs. He says it takes a million droplets of insecticide just to reach one adult mosquito. This destroys nature’s defenses as it kills the mosquitos predators too. His team only treats the true threats to public health by selectively targeting the 2 primary disease carrying larvae. They use B.T. They may apply a teaspoon of it to a 20 acre of marsh and, then, carefully monitor it. Carper says “we think that spraying pesticides for mosquitoes doesn’t outweigh the risk that they pose for both human health and the environment.” 

Direct quotes are from an article in the American Gardener magazine. The author of this article is Nancy Lawson.

So—don’t spray your yard. Instead, spray a long-sleeved shirt with repellent when you go out to work in the yard. Stay in at dawn and dusk. Don’t wear scents. And hope for the best.