Dorsett encourages town to change mosquito control program

A test conducted after aerial spraying in 2017 revealed just one of 161 dead insects was a mosquito.

MEEKER | Dr. Bob Dorsett has been trying to convince Meeker’s board of trustees that the annual aerial spraying of pesticides before Range Call is not the best way to control the pesky insects. This year he pointed out a new reason for the town to consider rethinking its mosquito control program: the algae overgrowth problem in the river.
Aquatic macro-invertebrates like caddisflies “graze” on algae and help limit its growth. Pesticides like the ones used in Meeker’s aerial spraying are extremely toxic to those aquatic insects, and could be a contributing factor in the algae problem in the White River.
“Insects are the ‘canaries in the coal mine’ for the health of the river. Insect populations drop dramatically below Sleepy Cat,” Dorsett said.
A local citizens’ group, the White River Alliance, has formed to reach out to property owners upriver to address the potential human causes for the algae overgrowth. Several upriver landowners, including Elk Creek, have agreed not to spray for mosquitoes this summer and are “looking to change to other methods.”

Mosquitos aren’t on anyone’s “favorite insect” list. Besides being annoying, the county has had two confirmed cases of West Nile Virus since 2016, according to Rio Blanco County Public Health. Whether the individuals contracted the disease from homegrown mosquitos cannot be confirmed. Recent outbreaks of other mosquito-borne illnesses have further increased concerns

Research conducted by Dorsett indicates spraying may not accomplish the desired effect: killing mosquitos, and is instead killing beneficial insects like bees (see chart).
The insecticides used now are “adulticides,” meaning they only “knock down” adult flying insects.
“Three or four days later you’re back to where you were. Larvicides take down an entire generation,” Dorsett said.
Larvicides cost a little more (10-15 percent) and have to be reapplied during the season.
The town has $5,000 budgeted for weed and pest control. According to Dorsett, the pest control portion kills a minuscule percentage of adult mosquitos for a few days.
The Centers for Disease Control recommend a multi-pronged approach to mosquito control, of which aerial spraying is only one aspect.

Aerial spraying of malathion/permethrin comprises less than 1 percent of spraying for mosquitos, according to the EPA, there are recommendations for people who may be sensitive to aerial spraying including staying indoors with the windows closed, covering and washing outdoor items like children’s toys and pet food dishes and contacting Poison Control in case of a reaction. (800-222-1222)

The Gunnison River has faced similar algae challenges recently.
“We are essentially duplicating the story on the Gunnison from six or seven years ago,” Dorsett said.
Gunnison changed their spraying program to eliminate aerial spraying of permethrin (which accumulates in sediment) and have seen a reduction in algal bloom. No one can say for sure if that’s the magic cure.