Aerial spraying for mosquitoes Thursday morning

Palo Alto Baylands treated by helicopter; another round next week

A helicopter assault against the summer salt-marsh mosquito in the Palo Alto Baylands began Thursday, Aug. 23, at about 7 a.m., the Santa Clara County Vector Control District has announced.

The district is trying to control breeding of the aggressive mosquitoes, which have plagued residents in Palo Alto and Menlo Park for several weeks.

Officials said spraying by helicopter is necessary because the areas where the insects breed are extensive and difficult to treat from the ground. The chemicals pose little danger to people, and there are no residences or businesses within the area to be treated, vector control officials said.

The mosquito -- Aedes dorsalis -- lays its eggs in the moist soil just above the water line. The eggs can lie dormant for a decade, even after repeated flooding. High tides and seasonal rains, together with the short days and cooler temperatures of winter, cause the eggs to hatch when they are submerged in water, according to officials.

The salt-marsh mosquito has not been shown to transmit West Nile Virus, but it is known to bite viciously during the day and can fly up to five miles from its breeding grounds to feed on humans and other mammals, officials said.

A broken tide wall in the Palo Alto Baylands has allowed water levels to rise and fall in the tidal basin, creating ideal conditions for mosquito breeding. Vector control officials have been closely monitoring the development of mosquito larvae, and current conditions are ideal for eggs to hatch.

Recent adult "fly-offs" have created considerable discomfort for residents and workers in nearby areas, according to officials.

Approximately 150-400 acres are being treated with environmentally safe products: methoprene, an insect growth regulator, and Bacillus thuringiensis var. israelensis (Bti). Bti is a natural bacteria that, when consumed by mosquito larvae, activates an insecticidal protein that kills the larvae.

These products act specifically on mosquitoes and are short-lived in the environment, officials said. The products control the immature (aquatic stage) mosquitoes but are not harmful to birds, fish, other insects, wildlife or humans.

Thursday's spraying is different from recent fogging operations that took place in Los Altos. Unlike the very low-volume aerosol that focused on adult mosquitoes, these applications are being applied at 10 gallons of water per acre, to thoroughly cover the marshes, officials said.

Access to the Baylands is restricted during the spraying, which could last until noon, but the area will open to the public immediately afterward, officials said.

Next week, the district will again take to the air but with a different, granular form of chemical. That form should be longer lasting and may obviate the need for weekly sprayings, said Russ Parman, Santa Clara County Vector Control acting district manager.

Santa Clara Valley Water District, which is in charge of the broken tidal gate, is awaiting permits and is preparing environmental documents prior to fixing the gate, spokesman Marty Grimes said. The district hopes to have a final permit from the state Regional Quality Control Board by the end of next week, he said.

But Sept. 4 would be the earliest that a temporary fix would be in place because repairs cannot be made until after the nesting season under the Migratory Bird Act.

"The good news is it will take one day to do a temporary fix," he said, adding the hole would be filled by pressure grouting.

Plans for a permanent fix are not yet in place but would likely involve digging out the old area and filling it in with concrete, he said.

Vector Control is encouraging residents to report places where mosquitoes are breeding and take steps to avoid getting bitten, such as wearing long-sleeved shirts and long pants and applying repellent when outdoors where mosquitoes are biting.

More information about mosquito prevention or the products used in spraying is available at Vector Control or by calling 408-918-4770.

Click here to view the map of the area being sprayed.


Posted by Mosquito Food, a resident of Duveneck/St. Francis
on Aug 22, 2012 at 6:37 pm


Posted by Sharon, a resident of Midtown
on Aug 22, 2012 at 6:47 pm

There is a massive plaque of West Nile Virus in Texas which is rapidly spreading to the West and will be here in late August-early September.

It is already here through human vectors who have visited Texas in the last 4 months

WNV causes chronic neurological diseases in 1 out of 150 of those infected.

AIDs, Cancer and transplant patients are dramatically more at risk

Bring back DDT-for home spray first-then for general spraying if needed.

Posted by Spray-Spray-Spray, a resident of Another Palo Alto neighborhood
on Aug 22, 2012 at 7:02 pm

It's about time that someone is doing something. If we had an honest City Council, they would have been demanding action much earlier. But this group is still secretly boosting HSR, and have no idea what is going on locally.

Wonder if anyone in the media will take the initiative to track down the chain of events that started with the break in the seawall, up to this aerial spraying. It would be really interesting to find out how long each of the intermediate events took before someone in the "chain of authority" actually took some action.

Calls into question how this bunch would provide public health services in a real crisis.

Posted by robit noops, a resident of Greenmeadow
on Aug 22, 2012 at 7:09 pm

yeah, that city council.....

want to know how quickly they will respond in the case of a zombie invasion.

Posted by Mark, a resident of Midtown
on Aug 22, 2012 at 7:10 pm

What about neighborhoods? People with standing water need to get rid of it. I think on Vector Controls website there is a bleach or something that will kill the larvae. Lets get these pesky buggers!!

Posted by Mosquito Food, a resident of Duveneck/St. Francis
on Aug 22, 2012 at 8:39 pm

@Sharon - 26 dead in Texas so far - given the panic monkey nature of media, I'm surprised it isn't a bigger story.

"The state has reported 586 West Nile infections and 25 deaths. Texas' public health director said during the briefing that at least four additional deaths were reported this week: one in Dallas, two in neighboring Tarrant County and one in nearby Collin County."

Web Link

Posted by always left out, a resident of Green Acres
on Aug 22, 2012 at 9:15 pm

Thanks palo alto online,

Once again you left out East Palo Alto, though the city is alot closer and live on the same side, than any city you mentioned on your article. I guess East Palo Alto nows how to combat the pest or mabe they have joined forces to bug their neigbors.

My guess is these flying stingers just fly over East Palo Alto, no good meat there.

Posted by allergic, a resident of Adobe-Meadows
on Aug 22, 2012 at 9:44 pm

"always left out" should learn how to spell (or at least know how to use spellcheck)

Posted by moi, a resident of Another Palo Alto neighborhood
on Aug 22, 2012 at 10:03 pm

Sharon ???? ---

You have outdone yourself:

DDT? Really?

Silent spring, anyone?

Posted by Red Itchy Bumps, a resident of Palo Verde
on Aug 23, 2012 at 6:45 am


Thank you. This infestation is the worst we've seen in 25 years. We are mauled the moment we step outside of our home. The kids complain continually of pain that these little blood sucking helicopters inflict.

On a side note....Why is there no information on repairing the Tide/Flood prevention walls? I can deal with a few hundred mosquito bites...but 24" of water in the living room would be ruinous.

How about some detailed reporting on why the failed wall was not detected prior to it giving way and what is being done to quickly repair it prior to the rainy season.

Posted by Ray, a resident of Professorville
on Aug 23, 2012 at 7:05 am

Precisely my thought. Attack the root cause instead of telling us the result. Mr. Khrushchev, build up that wall!

Posted by Penny, a resident of Greenmeadow
on Aug 23, 2012 at 9:08 am

A few questions:

1). What effect will this spray have on birds and other wildlife in the baylands?

2). What, if anything, is being done about repairing the broken tide wall which seems to be the root of the problem? What is the plan/timeline for making this repair?

3). Did a maintenance failure lead to this problem? Should we request assessment of other tide wall and levy maintenance? Is this failure a symptom of a bigger problem?

Posted by rational, a resident of Greater Miranda
on Aug 23, 2012 at 9:49 am

Better the birds than humans. Come on people.

Posted by Dan, a resident of Southgate
on Aug 23, 2012 at 10:03 am

Awesome! Will the helicopters be playing Ride of the Valkyries?

Posted by Red Itchy Bumps, a resident of Palo Verde
on Aug 23, 2012 at 10:34 am


From Wikipedia....

The Palo Alto Flood Basin was constructed in 1956 in order to prevent a repeat of the floods of 1955, when a high tide prevented the escape of heavy runoff from Matadero, Adobe, and Barron Creeks into the San Francisco Bay. The trapped runoff waters overflowed upstream creek banks and caused severe flooding in Palo Alto. In order to control the flow of water into the flood basin, a tidegate was placed at the confluence of Adobe Creek, Matadero Creek, and the San Francisco Bay, so that the flood basin could be maintained at approximately 2 feet below sea level, creating room to absorb floodwaters. The tidegate consists of several weirs and one operator-controlled sluice gate that enables tidal flows into the basin in order to improve water quality and for mosquito control. Three agencies oversee the tidegates: Santa Clara Valley Water District, City of Palo Alto, and Santa Clara County Vector Control.

Posted by Ronnie, a resident of Midtown
on Aug 23, 2012 at 11:06 am

Dan I was totally just thinking that!
I love the smell of "methoprene...and Bacillus thuringiensis var. israelensis (Bti)" in the morning!!

Posted by Ann Bilodeau, a resident of Community Center
on Aug 23, 2012 at 11:16 am

Palo Alto Weekly writers:
Please learn the difference between "lay" and "lie."
"The mosquito -- Aedes dorsalis -- lays its eggs in the moist soil just above the water line. The eggs can lay dormant for a decade . . ."
"The mosquito lays its eggs" is correct, but it should be "the eggs can lie dormant."

Posted by Tom, a resident of Midtown
on Aug 23, 2012 at 11:23 am

Sharon (and anyone else who may be under this misconception) -
West Nile Virus is not spread from person to person. See the CDC's FAQ on this at Web Link
The only exception I could find was a small number that probably occurred through blood transfusion and organ donation.

Also note (as reported in the story), this mosquito does not ("has not been shown to") carry WNV. I see other questions/comments that are also addressed directly in the story. Folks, please read before reacting.

Posted by musical, a resident of Palo Verde
on Aug 23, 2012 at 12:05 pm

Can a mosquito transfer WNV from person to person, or only from a bird to a person?

Posted by June Cleaver, a resident of South of Midtown
on Aug 23, 2012 at 1:30 pm

"Folks, please read before reacting."

Sharon, read before commenting? Surely you jest....

Sharon said "There is a massive plaque of West Nile Virus in Texas which is rapidly spreading to the West and will be here in late August-early September." Doesn't that sound like the Killer Bee invasion we heard so much about decades ago? Sharon and her ilk love the Fear, Inc. stories spread on Fox and the other fear monger websites.

Besides, Sharon, 'plaques' don't move very fast.....

Posted by OY!, a resident of Old Palo Alto
on Aug 23, 2012 at 3:05 pm

"the WNV plague is spreading west...." must be true cause I read it on the internet. The media stupidity of spreading misinformation has been outdone and outsourced by the new champion "The Internet" God Bless Ignorance!

Posted by College Terrace Mom, a resident of College Terrace
on Aug 23, 2012 at 6:16 pm

I am not debating the need for action, but as someone with respiratory disease, I would have appreciated advance notice allowing me to leave Palo Alto or stay inside with my doors and windows closed.

Posted by Resident, a resident of Another Palo Alto neighborhood
on Aug 23, 2012 at 6:30 pm

Advance Notice

I got email about this, I read about on Palo Alto Online, it was on one if not more of the local news stations last night and again this morning. I think it was on the radio too.

How much advance notice should we get?

Posted by Mr.Recycle, a resident of Duveneck/St. Francis
on Aug 23, 2012 at 11:49 pm

Are you really worried about spraying in the Baylands when you live in College Terrace? I'm sure the pollution from traffic on El Camino is about 100,000x more dangerous to you, and it isn't dangerous. Don't sweat it, and don't lock yourself and kids inside.

Posted by Ko, a resident of another community
on Aug 24, 2012 at 4:06 pm

When did the operation finish?
Around 8:00 am?

Posted by Brian Schmidt, a resident of Mountain View
on Aug 24, 2012 at 4:22 pm

I'm the Water District director for this area. Who has experienced really bad mosquitoes? I'd like to find out - I went out to the Basin itself and didn't find any, but it was somewhat breezy and maybe not the best place for them right now.

I agree with the comment above that the flood control aspect is the most important issue. The interim fix should take much less than a week to do, we can start in early September and will start as soon as allowed, and we don't start worrying about flooding until mid-October.

Posted by Flabbergasted, a resident of Old Palo Alto
on Aug 24, 2012 at 6:54 pm

We're getting nailed in Old Palo Alot, but since the spraying, I notice fewer mosquitos.

Mr. Schmidt.... mosquitos don't fly well in breezy conditions. And, I just do not believe it was reasonable for the responsible experts in this leak issue to have expected a leak would not get worse as indeed it did. If you want more taxes for your budget this November you and your colleagues have a lot of work to do starting with being 100% transparent by naming those who let this gross negligence happen and make them truly accountable. Otherwise, you look like a bunch of bumbling idiots I would not trust to put a straw into a glass of water without splashing it all over the place.

Posted by Brian Schmidt, a resident of Mountain View
on Aug 24, 2012 at 9:22 pm

My expectation is that the flood control issue will be resolved well before the rainy season. The public will be able to judge whether that's true in very short order.

The mosquito issue is an annoyance, and I'm sorry that the flood control basin, which has also served to reduce mosquito populations that would otherwise be here every single summer, isn't doing that for the last several weeks. I just went back to the area this evening - several bites over about a 5 minute period.

I'm checking with staff, but it seems the opportunity to fix this is between the end of migratory bird nesting season and the beginning of rainy season. The initial problem was found last November. I believe we were trying to reduce costs by figuring out what would be a permanent fix rather than immediately jumping to construct an interim fix as we now find that we need to do. Again, I'll check with staff to confirm.

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