Meeker’s celebratory Fourth of July spraying has resumed. I have fresh data on the results of that spraying but no new conclusions. I might as well recycle the report from 2017—or from 2002 or any of the intervening years.
With my wife’s help, I sampled insects knocked down by aerial spraying ahead of the Fourth. We’re not directly on the flight path, but insecticide drifts to us on the breeze from the flight paths along the river and Sulfur Creek. We counted insects that fell on a two-meter square sheet, spread on the ground under vegetation for half an hour. That’s a standard collection method.
A control sample before spraying found 15 leaf hoppers, five gnats, and one mosquito, all alive. The sample immediately after aerial spraying found 34 gnats, 14 dipterids, four beetles, two weevils, two plant bugs, two leaf hoppers, one brachonid wasp, one lady bug larva, one halictid bee and one andrenid bee. All dead.
There were no mosquitoes in the after-spray collection. They came out the following evening, though. I counted two bites in a 10-minute exposure, six bites in the evening two days after the spray.
Just a few thoughts for the obituaries. Brachonid wasps prey on aphids and other garden pests. So do lady bugs. The two little bees you wouldn’t notice unless you’re looking close. But they’re among the critical pollinators for our wildflowers. And they’re endangered by habitat loss and competition with commercial bees. Against Univar Chemical Corp., they don’t stand a chance.
Scale this count up to the numbers of dead insects all along the spray paths through town. As a minimum estimate, we knocked down four million beneficial or otherwise harmless insects. Certainly the spray killed some adult mosquitoes, just not at our sample site. As in years past, aerial spray with adulticides kills very few target insects (mosquitoes and other pests) in comparison with the slaughter of harmless and beneficial insects. And, as usual, the mosquito population bounces right back, within a day or two, with the next larva hatch. Just like in years past.
Town and County need to adopt a sensible and effective insect pest management program. The present plan is neither. It causes far more harm than benefit, and it does not control the mosquito population (even assuming that population is more than just a nuisance). In the interval until our local governments adopt an integrated pest management plan, and as an essential component of that plan if it ever occurs, individuals can protect themselves with some basic measures. Drain or frequently change standing water around the home, e.g. in ponds, bird baths, dog bowls, old tires, etc, where mosquito larvae develop. Apply Bti pellets to standing water that can’t be drained. (Bti is a larvacide specific to mosquitoes and harmless to other organisms.) Wear long pants and long sleeves, especially in the evening when mosquitoes are most active. Apply insect repellant containing DEET if you’re out and the critters are a bother. (Other repellants are available, too, but not as effective.)
If you get bit, swat the critter, and keep a tally for the records. See if human reflexes can do a better job controlling mosquitoes than the celebratory chemical mist.
Bob Dorsett, MD