TWIN FALLS — Three years ago, health officials predicted Idaho could be hit hard any time by the West Nile virus. Last week, three Twin Falls County commissioners began a process to control the mosquitoes that carry the virus.

On Wednesday, commissioners Tom Mikesell, Gary Grindstaff and Bill Brockman approved a resolution that allocates money for a natural larvicide that kills the eggs of virus-carrying mosquitoes.

As of Sept. 15, there have been 718 reported cases of West Nile in humans. Eighty percent of human cases are not reported because symptoms are either mild or nonexistent. Idaho leads the nation this year for the virus.

The commissionersÂ’ action is good news for organic producers and fish farmers, who have complained to commissioners they donÂ’t want chemicals spread throughout the county by airplane.

Buhl resident Theresa Strolberg, an organic producer, was jubilant on Wednesday when she heard the commissionersÂ’ decision.

“I think it is a wise decision,” Strolberg said. “I think aerial spraying should never be done because it is dangerous to everyone and everything.”

However, just because commissioners are choosing to go with a natural means for the time being, that doesnÂ’t mean they might not have to use more aggressive measures sometime in the future.

“It’s one step in what will be many steps,” Mikesell said. “Hopefully it will reduce the population of mosquitoes next year.”

On the east end of the county, Murtaugh resident Shala Hepworth is gathering signatures to ask voters in November, according to state law, to approve a mosquito abatement district. And on the west end, Jim DeKleinhans is gathering signatures in hopes that he can force commissioners to declare a state of emergency so aerial spraying of chemical insecticides can begin.

Under state law, county officials could declare an emergency to protect agricultural animals. With a killing frost due shortly, commissioners say they are going with the most conservative method because it will reduce the spring hatch in 2007, plus give county workers more time to locate the hot spots for the troublesome mosquitoes.

Grindstaff said if the county went with chemical spraying, some producers would have to wait 30 days, until residue had dissipated, to sell their crops. Also, studies have shown aerial applications of the chemicals used to kill mosquitoes will prevent weight gain in trout, the production of which accounts for a $100 million industry in western Magic Valley.

The active ingredient of the natural larvicide the commissioners chose is called Baccillus sphaericus, or Bti. The commercial name is VectoLex. People who have standing pools of water of any sort can get it for free at the county extension office, but they must fill out paperwork proving they have a need for the product, commissioners said.

Bti comes in briquettes that will dissolve in water over three to four weeks. Kali VanLeeuwen, Twin Falls County Weed and Pest Control supervisor, said she has discovered mosquitoes with West Nile on both the east and west ends of the county.

Though it is estimated that between 750 and 1,000 mosquitoes can hatch from a mud imprint of a cowÂ’s hoof with one-inch of standing water, she said so far she has not found any West Nile virus-bearing mosquitoes on or near any dairies.

“Even though mosquitoes like to lay eggs where there’s lots of organic matter, we haven’t found any near lagoons,” she said.

She speculated the compounds and swirling water in most lagoons repel the insects.

Bud Compher, Filer public works supervisor, said he has been using the larvicide since last fall in the storm drains throughout Filer. And since then, heÂ’s observed very few mosquitoes. VanLeeuwen said she has received virtually no complaints about mosquitoes this year from Filer residents.