From the pages of
Sublette Examiner
Volume 8, Number 17 - July 17, 2008
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Ineffective Mosquito Spray Has People ‘MAD’

by Derek Farr

They didn’t die like they should have.

On July 3 the weather was ideal. The evening was perfectly calm and dry. But something happened. The mosquitoes didn’t die.

Those circumstances are the topic of an 8 p.m. meeting hosted by Sublette County Mosquito Abatement District (MAD) #2 tonight (Thursday) at Big Piney Library.

On July 3, the district used a new pesticide for the first time.

“It’s a greener chemical if you will,” Jeannie Robinson, MAD#2 clerk, said. “It’s better for the environment.”

The new chemical, Aquahalt, is a water-based, synthetic insecticide derived from chrysanthemum flowers. It is applied as an ultra-low volume spray dispensing fine aerosol droplets that stay aloft and kill adult mosquitoes on contact.

Aquahalt’s application is precisely the reason July 3 was such a good day to spray. Not a drop of rain in the air and calm winds should have equaled a massive kill, but the results weren’t encouraging.

“The (mosquito) counts were just outrageous around the Green River,” Robinson said. “Post-spray they were way up. I think we had over 2,000 in one night.”

The counts are done using mosquito traps. Before the spray, Robinson estimates amosquito count of 550 from the Green River trap.

Throughout the 30,000-acre MAD #2, which comprises Big Piney, the Big Piney cemetery district, Marbleton, Wild Horse Subdivision and the Sublette County Fairgrounds, the results were virtually the same Aquahalt didn’t work.

“The only positive comment that I had is they didn’t have to keep their windows closed two days after spraying so their house wouldn’t smell like bug spray,” Robinson said. “That was the only positive comment I’ve had.”

The chemical’s performance was disappointing and expensive.

Aquahalt sells for $180 a gallon. It requires about 350 gallons to spray MAD #2 twice. That equals $69,300 in mosquito-control chemicals, which so far haven’t worked.

The decision to use Aquahalt came about for several reasons. First the chemical is safer for the environment. An application of Aquahalt requires 3/4 of a teaspoon per acre. Malathion, the chemical MAD #2 has been using for 10 years, requires 3 ounces, roughly two shot glasses’ worth, of chemical per acre.

Another reason for the change is resistance.

“After you use Malathion for so many years, it efficacy is not as good as when you first started using it,” Robinson said.

But perhaps the most compelling reason to change was Aquahalt’s success elsewhere. Montpelier, Idaho, Uinta County and JacksonHole have had luck with the chemical.

So why didn’t it work in MAD #2?

On Thursday MAD #2 is bringing in two top executives from Clarke Mosquito Control, the makers of Aquahalt, to answer some questions.

“We are going to spend all day Friday going over the terrain, the type of climate we have, how the chemical was stored, all the different variables that could affect this,” Robinson said. “I don’t know if we need humidity, don’t need humidity; I don’t know what those parameters are. That’s why they are coming in.”

Friday night, MAD #2 is scheduled to spray the rest of its Aquahalt for its second spraying of the year.

Robinson wants dead mosquitoes. She doesn’t want a refund; she wants her money’s worth. “If it takes two more sprayings I expect them to do something along those lines,” she said. “After spending that kind of money for a chemical it needs to work. I want to see that the people’s money is spent wisely. That’s why we have the big guys coming in to let us know about their product. I want to know what went wrong and why it went wrong.”

While some questions will be answered at Thursday night’s meeting, the real test will come when Robinson checks the Green River mosquito trap after the spraying.

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