If the local agency charged with combating the West Nile virus is holding out for a breeze-free evening to resume its aerial assault on mosquitoes, it may be waiting for some time, weather watchers say.
For the third consecutive night Sunday, breezes exceeding 10 mph prompted Sacramento-Yolo Mosquito and Vector Control District officials to call off plans to blanket up to 66,000 acres of southern Sacramento County with insecticide. Thursday night's spraying was cut short by wind.
"We just wanted to make sure the weather is working in our favor, and it's not," said Jennifer Benito, spokeswoman for the agency. "If wind is above 10 mph we don't go up."
Officials said they made the decision not to fly at 5 p.m. so residents could be notified.
Health officials say the spraying is needed to combat the West Nile virus, which is spread through infected mosquitoes. The virus has killed one local man, resulted in 36 confirmed human cases within Sacramento County and killed more than 12,000 birds within the county.
Officials said the three days of spraying EverGreen Crop Protection EC 60-6 over northern Sacramento County was effective, resulting in mosquito kill rates of between 40 percent and 80 percent, depending on the location.
But efforts to treat Sacramento County south of the American River have been harder to get off the ground.
National Weather Service meteorologist Robert Baruffaldi said he expected Sunday night winds of between 15 and 20 mph, only slightly less than the 20 to 25 mph winds Friday and Saturday evenings.
Benito said she wasn't prepared to answer what happens if Sacramento's summer cooling system - the Delta breeze - continues to kick up nightly.
"It looks like (the Delta breeze) is generally going to stay in the same range for the next few days," Baruffaldi said.
"I don't know about it spraywise, but it has kept our temperatures in the low-to mid-80s, which has been a nice break from the 100-degree temperatures," he said.
In an interview earlier this weekend, David Brown, manager of the vector control district, said he was "extremely concerned" that the delays could allow mosquitoes to continue to thrive and spread the virus.
The delays in aerial spraying also make it harder for the public to remain aware of the situation.
Officials said residents in the spray zone are not at risk and need not take any precautions, but those seeking to limit their exposure are encouraged to stay inside and keep doors and windows closed between 8 p.m. and midnight, turn off air-conditioning and ventilation systems and bring in or hose off patio furniture, toys or other items left outside.
While many have raised concerns about the spraying and some initially sought to halt the plan before the first plane got off the ground, others are not so worried. Sacramento resident Misty Devoll said most people are regularly exposed to far more dangerous substances.
"I think they totally should do it," said Devoll, interviewed Sunday in Hollywood Park.
Because she believed the chemical used - a pyrethrin, extracted from chrysanthemum flowers - was safe, she said, she didn't plan to take any precautions and was not inconvenienced by the wind delays.
WHAT TO DO IN SPRAY ZONES
Officials say residents in the spray zone are not at risk and do not need to take precautions for themselves, pets or livestock. For those who remain concerned, they're suggesting ways to reduce exposure:
* Stay inside and keep doors and windows closed between 8 p.m. and midnight. The mist stays in the air up to 90 minutes after release.
* Turn off air conditioning or ventilation systems during spraying.
* Bring patio furniture, toys and pets indoors for the evening. Cover items left outside.
* Remove shoes before coming inside until spraying ends.
* Wash outdoor furniture and other items people might touch. But don't create pools of water that could become mosquito breeding grounds.
* Fruits, vegetables and herbs from gardens should be washed but will be safe to eat.
* Swimming pools do not need to be covered and will be safe after the applications.
For more information, call (800) 429-1022 or check www.fightthebite.net.
About the writer:
- The Bee's Ed Fletcher can be reached at (916) 321-1269 or email@example.com.