Mosquito abatement

Kamron Farnsworth, a drone pilot hired by Bannock County, demonstrates how the county’s new drone uses a pesticide to combat mosquitoes in an effort to prevent the spread of West Nile virus.

POCATELLO — Bannock County can now kill mosquito larva and eradicate noxious weeds in places that were previously inaccessible, thanks to a new drone designed to spray herbicide and pesticide.

Last year, Bannock became the first county in the U.S. to use a drone to target either weeds or mosquitoes, using a small drone that sprayed only liquid products. Idaho’s Madison County followed suit a short time later.

“I guess you can call it pretty cutting edge here,” said Dave Herter, who supervises both the county weeds and mosquito abatement programs.

This year, Bannock County’s noxious weed and mosquito abatement programs split the cost of buying a $32,000 drone, which also has an attachment for applying a dry larvicide — a bacteria found naturally in soil that is toxic only to mosquito and black fly larva.

The new drone made its 101st flight on Wednesday, treating the Portneuf Wellness Complex pond.

“With a lot of our other equipment, it would take us a long time to get into areas or we couldn’t even get into those areas,” Herter said. “Because of access with the drone, we’re able to fly in and take care of that issue.”

Herter hired Stephen Harker, who graduated from Idaho State University’s drone program in May, to pilot the new drone.

Harker explained the drone often follows an automated flight plan, spraying treatments according to a preprogrammed prescription map.

“If we’re doing an area that has a lot of slope and terrain and a lot of trees, or is close to power lines and poles, I will fly it manually,” Harker said.

Herter’s other approach to treating mosquitoes involves spraying water bodies from banks, often far removed from the major problem area. His conventional equipment also has a hard time in marshes, as it would sink into the muck. With the drone, he can spray from above into precise target areas, also saving on chemical costs through improved efficiency. With weeds, Herter can easily access steep and rocky hillsides that would be too tough to reach by staff hauling spray packs or riding four-wheelers.

“We can go in with this and do acres in a matter of minutes where it would take guys two or three days with a backpack,” Herter said, adding the drone also doesn’t leave a footprint on the ground. “I think we have dramatically stepped up our program.”

Herter relies primarily on word of mouth to find pockets of noxious weeds to spray. The drone has been used heavily thus far in spraying dyer’s woad on steep hillsides between Inkom and McCammon.

His staff members set out mosquito traps and collect water samples, testing them for larva, to determine where to attack mosquitoes.

Deb Hahn is tasked with analyzing mosquito samples to determine the species composition of populations and if any individual bugs are positive for West Nile virus.

“Once we identify an area, then we really concentrate on that area,” Hahn said.

No mosquitoes have tested positive for West Nile yet this year, though Hahn has found several samples of Culex pipiens and Culex tarsalis mosquitoes, which are primary carriers of the virus.

In 2006, Idaho led the nation in the prevalence of West Nile. Bannock County had no confirmed West Nile samples last year but had to declare an emergency for West Nile during the prior year, when 11 mosquitoes tested positive, Hahn said.

The county’s annual mosquito abatement budget is about $200,000. The county invests between $300,000 and $350,000 per year on controlling noxious weeds, Herter said.