City of Powell Sanitation Department workers deployed its airborne insecticide Biomist for the fifth and possibly final time Sept. 7, after a mosquito fogging year that began later than normal. 

“Mosquito spraying ends late August early September depending on our trap counts,” said Sanitation Superintendent Allen Griffin. “Most years (Sept. 7) would be the last time of the year. If trap counts warrant we could still fog again.”

He said they will usually leave the traps out until around Sept. 15, although with school starting and people having less time out at night before it gets dark, they receive few complaints about mosquitoes this time of year. 

He said it’s been an average mosquito season in town and the department has fogged five times, the first on July 26. Often fogging begins in June. Griffin said the results of fogging are immediate, as the insecticide is meant to kill mosquitoes in flight when they come in contact with the airborne droplets.  

Staff has also put larvicides in storm drains twice, a process which impedes the development of mosquitoes in their prime hatching grounds around standing water. 

The department had much more funding for this year’s work as compared to last year, as it received a $9,650 grant from the Wyoming Department of Agriculture to help control West Nile virus. 

That funds fogging, larvicide and trapping mosquitoes to get a count that determines when the process begins each summer. 

Last year, the grant provided $3,750, which Griffin said earlier in the year was was a low year for funding. 

According to the Wyoming Department of Health, West Nile virus has been identified in all Wyoming counties, although less than 1% of infected people develop a serious, sometimes fatal, neurologic illness. Since 2012, there have been two fatal cases in the state, including one in Park County in 2013. 

Permethrin, the active ingredient in Biomist, affects the nervous system in insects, causing muscle spasms, paralysis and death. Biomist is manufactured by Clarke Mosquito Control. More information about the spray is available at international.clarkemosquito.com.

Weather permitting, spraying begins at dusk and takes about four hours.

If you do not want your property to be sprayed, call the city at 754-5106 to be put on the no-spray list. For more information about the City of Powell’s mosquito-control program, contact the Sanitation Department at 307-754-6941.