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Anti-West Nile effort enlists mosquitofish to gobble larvae

While the puddle created by a leaky pipe in Jeff Hadden's backyard never got deeper than an inch or so, it spawned a mosquito population so thick, he said, that "it looked like a black cloud over the water."

Unfortunately for the mosquitoes, Hadden is the owner of Natural Pest Control and raises mosquitofish in his backyard. All he had to do was pick up a few fish, put them in the trench, and let them work their magic.

"In two days, all the mosquitoes were gone," he said.

Mosquitoes have long been an annoyance, especially in the hot summer breeding months. Now, the pests are moving beyond nuisance. Fear of mosquito-spread West Nile virus, which can be fatal, has forced local governments to take drastic steps, including approving a plan to drop insecticide north of the American River for three nights beginning Monday, and in populated areas of southern Sacramento County as soon as Thursday.

Area mosquito officials say the spraying is needed because the rate of mosquitoes infected with the virus is exceptionally high and they want to prevent an epidemic.

David Brown, general manager of the Sacramento-Yolo Mosquito and Vector Control District, said Saturday that spraying will start Monday between 8 p.m. and 8:45 p.m. - "when it starts to get dark and mosquitoes are active and when meteorological conditions are correct."

In an e-mail in response to Bee questions, Brown also said that, at the concentrations the district is using, animals and pets "should not be affected, but if people are concerned, they should bring them inside."

Along with spraying, mosquitofish are on the front line of defense against West Nile virus. The mosquito and vector control district makes them available for free for homeowners.

Armed with a map of known mosquito-breeding locations, employees of the Sacramento-Yolo Mosquito and Vector Control District head out with mosquitofish and larvacide trying to negate the problem.

And the silver-and-olive fish, known for their thick skins and healthy appetites, are up to the task.

"The fish are hearty and eat everything," Hadden said. "I've never sold to a person twice. Without predators, the fish will be there until the pond dries up."

According to Woody Schon, the senior fish culturist at the Sacramento-Yolo Mosquito and Vector Control District, recent trends in home landscaping have escalated an already-dangerous problem.

"Since 9/11, everyone has this back-to-the-yard mentality," he said. "Everybody and their brother has a backyard pond. But most people are oblivious to the potential of those ponds breeding mosquitoes."

Schon said most mosquitoes are found in suburban locations, not the uninhabited backwoods of yesteryear. The shift poses new dangers now that the vector control district has found that one in 10 local mosquitoes are infected with the West Nile virus.

"I've never heard of a higher infection rate," Schon said.

Despite its small size, the mosquitofish's appetite allows it to decimate mosquito populations. The large lower jaw gives the mosquitofish an upturned mouth, and the fish voraciously attacks anything on the surface, especially mosquito larvae.

For the tiny fish, no job is too small. From small plots of standing water to large ponds, they're capable of cleaning out anything that finds it way to the water's surface.


Local vector control districts have plenty of mosquitofish available. To obtain free mosquitofish, or for answers to questions about how to prevent mosquitoes from breeding in your neighborhood, call:

* Sacramento-Yolo Mosquito and Vector Control District: (916) 685-1022 or (800) 429-1022.

* Placer Mosquito Abatement District: (916) 435-2140.


Concerned about mosquitoes? Here are some easy tips to make your home safer.

* Make sure your window screens fit properly - it doesn't take much of an opening for a mosquito to make an entrance. Mosquitoes are drawn to the carbon dioxide we exhale, so they're actively looking to find their way toward you.

* Watch your watering. Even an inch of water in a flower pot can produce dozens of mosquitoes. In particular, large plants in pots can become centers for standing water.

* Be vigilant about standing water. Everything can become a potential breeding ground - such as a large water dish for a pet or a poorly cleaned gutter. Clean these spots out when they're not in use and track them for larvae.

* Maintain your backyard. It's easy to let ponds and pools fall into disrepair during the scorching summer heat. But these can make great spots for breeding mosquitoes. If you've got a pond, make sure you add some mosquitofish to avoid problems with the insects.

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