The issue of mosquito fogging has hit the public consciousness with the recent fogging in Longmont.

I'm a strong believer in the sanctity of private property, and last year a judge in Delta County ruled that mosquito fogging violated the private-property rights of my clients, and created a trespass. The court issued a permanent injunction to prohibit any pesticide from drifting onto my clients' property. It's the first decision of its kind in Colorado, and one of the few in the country, holding that pesticide drift can pose a trespass.

My clients were organic farmers in Hotchkiss, an important area for organic farming. One of my clients also had leukemia. His next-door neighbor was part of a group of guys who fogged Hotchkiss for mosquitoes on a weekly basis during the West Nile virus influx in the mid-2000s. Ironically, this neighbor's wife contracted West Nile virus in 2006.

Communities that fog the most have a disproportionate amount of West Nile virus. Why? Mosquitoes develop pesticide resistance. This is recognized by the CDC. They are also killing the dragonflies and other insects that take a huge chunk out of the mosquito population.

Also, mosquito spraying, called adulticiding, is absurdly ineffective. You have to hit the mosquito with the droplet. The pesticide will go through the screen door into the house, but it's not going to kill the mosquito behind the house. That's why the kill rate with an adulticide is a paltry 50 percent. The horse is already out of the barn if you have to fog for mosquitoes.


By contrast, smart communities larvacide and only larvacide, using a scientific trapping and sampling protocol before the mosquitoes have hatched. One drop of BTI kills millions of eggs and mosquito larvae. And most importantly, you're not exposing your population to a likely human carcinogen, permethrin, and its sister in the Longmont formulation, BPO, a possible human carcinogen. Some in Longmont were quoted in the paper as saying permethrin is safe. That's not what the literature shows. Kids exposed to pyrethroids like permethrin were three times more likely to experience developmental delays, according to a study in the February 2011 issue of Pediatrics. It's also a hormone disrupter, mimicking estrogen and causing the sex organs of female lab animals to grow and male sex organs to shrink. I kid you not.

Maybe this spraying would be worth considering if there was an epidemic. While 2012 had an unexpected uptick in West Nile virus fatalities, 286, comparable to the number of a decade ago when the virus was at its worse, this pales in comparison to the 36,000 deaths per year from influenza. In 2013 there have only been 23 cases (no deaths) in the entire U.S., and only one in Colorado, on the Western Slope.

The alarmist attitude toward mosquitoes makes us, and our kids, afraid to go outside. And the pesticide fogging is killing our butterflies, dragonflies and bees. The WNV numbers simply don't justify our alienation from nature in this way.

Randall M. Weiner runs a three-person environmental law firm based in Boulder.