Rule Takes Bite Out of Anti-Mosquito Effort

One of summer’s most incessant pests has turned out to be a big beneficiary of a new policy protecting California’s waterways: the bloodsucking, disease-carrying mosquito.

Local agencies charged with hunting down and killing the insects say their never-ending battle suffered a severe blow last month when the state adopted restrictions on the use of aquatic pesticides--their best weapon against mosquito larvae.

No longer will officials be able to spray wetlands, lakes or other bodies of water--the most popular incubators for mosquitoes--without a state permit that requires a battery of costly water-quality testing.

The Sacramento-Yolo Mosquito and Vector Control District, one of the largest in the state, has suspended the use of some aquatic pesticides to avoid spending millions of dollars a year on testing, said David Brown, the agency’s executive officer.

“I have a huge problem, and I think it could seriously impact our ability to control mosquitoes,” said Brown, whose workers now use less-effective aerosol pesticides.

It’s a dilemma faced by officials throughout California.

Robert Sjogren, general manager of the Orange County Vector Control District, said the testing could cost his agency $1.5 million a year--gobbling up half his budget. The only way the agency could afford it would be to curtail spraying, or seek a tax increase, usually an unpopular option in conservative Orange County. More mosquitoes or higher taxes--those are the choices, he said.

“We are being included in a sweeping mandate at the public’s expense,” Sjogren said. “Our responsibility is to protect public health at the lowest possible cost. So where would the money come from?”

The new restrictions were adopted in July by the state Water Resources Control Board as part of its effort to enforce the federal Clean Water Act. The curbs also affect farmers and local water districts, since they use chemicals to keep waterways and reservoirs free of mosquitoes and algae.

The action was prompted by a federal appellate court ruling in March that held government agencies liable for damage caused by aquatic pesticides, even those approved by the Environmental Protection Agency.

Of all the parties affected, California’s local mosquito control agencies were among the hardest hit because they spray pesticides on hundreds, and in some cases thousands, of bodies of water each year.

The Greater Los Angeles County Vector Control District treats about 60,000 sites several times annually for mosquitoes, including wetlands, lakes, ponds, catch basins, puddles and even backyard pools, said Jack Hazelrig, the agency’s general manager. The Orange County agency treats as many as 30,000 sites, Sjogren said. And since the agencies are funded through taxes, any rate increase would require voter approval.

“If, because of a budget crunch, we have to lengthen the time between treatments, it means you’re going to have mosquitoes coming out of those sources,” Hazelrig said. “When that happens, you’re increasing the nuisance factor. And if those mosquitoes are infected with any of those diseases, you have an increased risk of infecting humans.”

The national Centers for Disease Control and Prevention estimates that 100 to 200 people in the country every year contract encephalitis or other diseases carried by mosquitoes, said Roger Nasci, a CDC research entomologist.

In California, such cases are rare. Not since 1997 has there been a reported case of a mosquito-borne illness, said Stan Husted, a biologist with the state Department of Health Services who believes abatement programs are largely the reason.

The use of aquatic pesticides in California became an issue after an Oregon irrigation district failed to follow label instructions when it used the herbicide Magnacide H to treat canals. Some of the herbicide seeped into a nearby river and killed thousands of fish.

An environmental group sued the district under the Clean Water Act, saying the agency should have obtained a pollution discharge permit before applying the agent to the canals. The court ruled for the district, saying that because the pesticide had been approved by the EPA, it did not require a permit. However, on appeal a federal court overturned the decision, saying the district should have obtained a permit regardless of the EPA’s approval.

California water board officials say its new permitting policy, which includes the controversial testing mandate, will protect the agencies from similar lawsuits. The state is leaving it up to regional water boards to grant exemptions.

The Santa Ana Regional Water Quality Control Board, which covers Orange, Riverside and San Bernardino counties, will review exemption requests on a case-by-case basis, said Gerard Thibeault, the executive officer. But vector control districts still must submit testing plans, he said.

“We’ll need to work with the districts to make sure they do enough testing, but don’t do any unnecessary work,” he said.