Davis Community Pushes Back on West Nile Spraying, Council Subcommittee to Study Issue

wnv-sprayingThe Davis community spent about a half hour overwhelmingly expressing their concerns about the aerial spraying for West Nile virus, the impact of the spraying, its effectiveness and need, as well as the impact on the environment and the native insect population.

Councilmember Brett Lee stated, “I think there is a reasonable concern about the agents that are used… I don’t think you can make a blanket statement that these are safe, these will not cause harmful effects to the residents of Davis.”

The response from Chris Barker, the Davis representative to the vector control agency was, “I wouldn’t dismiss concerns about harmful effects. I just don’t think there is any evidence to show that they have caused autism, for example. I think the study authors would agree with that assessment.”

Councilmember Lee then made a motion, “I would like to make a motion that we have a subcommittee that works with Gary Goodman at the vector control district and concerned parties in the community to come up with some possible improvements to the vector control district program – some improvements for Davis or perhaps the entire district.”

Councilmember Lee saw this as an effort to work together to help improve the situation. The subcommittee would be Brett Lee and Robb Davis and would report back to the council and the community.

Robb Davis said he saw this as a way “to improve local efforts at vector control, I think that’s really the intent. Find ways to do that at a community based level. I think that’s a good thing.”

Mayor Dan Wolk thanked the public for “the absolute valid concerns that were brought to us.” He added, “I definitely share those concerns.”

Mayor Wolk also addressed concerns expressed by members of the public who commented that the council truncated public comments down to two minutes and did not have a parallel presentation by those in the community with expertise and alternative views.

Mayor Wolk stated that unfortunately these are the limitations of having this discussion at the council level. “I do think if we have a future discussion on this, I think maybe more of a workshop format or even if it’s a community discussion about it, it would be helpful.”

The city council would adopt the discussion unanimously.

Watch the video below for the public comments on this topic:

—David M. Greenwald reporting

About The Author

David Greenwald is the founder, editor, and executive director of the Davis Vanguard. He founded the Vanguard in 2006. David Greenwald moved to Davis in 1996 to attend Graduate School at UC Davis in Political Science. He lives in South Davis with his wife Cecilia Escamilla Greenwald and three children.

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  1. Don Strong

    Three important areas to explore: 1. How effective is spraying at reducing the particular mosquitoes that carry the virus? 2. What are the collateral effects of the spraying? 3. How effective would alternative control strategies be? All three are difficult questions that are expensive to answer.

    1. Don Shor

      Your first question is easy to answer, since they monitor traps. For the second, there’s plenty of literature on impacts on beneficial insects and other non-target organisms. As to impacts on people, it will be hard to separate the science from the myths. Alternative control strategies are significantly more expensive.
      Key questions for me would be what metric triggers the aerial spraying, and how independent experts assess the efficacy.

        1. Don Shor

          Something I’ve been curious about is whether West Nile is now just considered endemic in the corvid population. And, for that matter, in the human population (ie, what percentage of Davis residents would now test positive for WNV).

          1. Robb Davis

            It is a question I have too Don. It was on my list to ask last evening but time ran short. I want to raise this, along with some questions about WNV morbidity. I think we will be able to deal with these and other questions as we move forward with the sub-committee’s work.

        2. Rich RifkinWDE 73

          FRANK: “We would also need to include the collateral effects of not spraying… the loss of birds and the potential risk for citizens to contract West Nile.”

          I am quite saddened by the nearly total wipe out of the Central Valley Magpie population by WNV. These yellow-beaked birds, related to crows, are disappearing.

          Regarding harm to bees: My understanding is that a far bigger threat to bees from WNV spraying is the use of neonicotinoid pesticides. Those chemicals are thought to be wiping out entire bee colonies.

          By contrast, the class of chemicals used to kill WNV mosquitos, while also very toxic to bees, can largely not harm bee populations if they are used correctly, based on the time of day bees tend to be active.

          Here is a warning from Trumpet EC:

          “This product is highly toxic to bees exposed to direct treatment on blooming crops or weeds. To minimize hazard to bees, it is recommended that the product is not applied more than two hours after sunrise or two hours before sunset, limiting application to times when bees are least active. Do not apply this product or allow it to drift to blooming crops or weeds while bees are visiting the treatment area, except when applications are made to prevent or control a threat to public and/or animal health determined by a state, tribal or local health or vector control agency on the basis of documented evidence of disease causing agents in vector mosquitoes or the occurrence of mosquito-borne disease in animal or human populations, or if specifically approved by the state or the tribe during a natural disaster recovery effort.”

          1. Don Shor

            Those chemicals are thought to be wiping out entire bee colonies.

            The impact of neonics on European honeybees is much more ambiguous, actually. Impact on other beneficials is another big issue. As to WNV spraying, as you note the bees are in bed when it happens.
            Here’s a detailed article on the impact of WNV on birds in California: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892874/

          2. Rich RifkinWDE 73

            Thanks for that link, Don. It confirms what I have witnessed the last several years: our local magpie population is way down. By contrast, crow populations dipped several years ago, after WNV first showed up here, but they have rebounded, and it seems like they are effectively replacing the magpies.

            The other local bird which that study mentions has been harmed badly by WNV is the scrub jay. I have also noticed its decline in our region. However, a friend of mine who lives up in the foothills of the Sierra Nevadas tells me scrub jays are now much more common up there. He said that he had heard that climate change caused them to move up to the foothills. I don’t know if that is true or not. But I can imagine climate change somewhat affecting the food/drink source for scrub jays.

          3. Don Shor

            Just anecdotally, magpies have barely nested on my property for years, and they were much more numerous before WNV. Now they pass through in small numbers. It used to be weeks and weeks of raucous behavior through nesting season. I heard one today; usually there would be a dozen or more screaming for much of the day. It was like having drunken parrots carousing in my trees all day long.
            As to the scrub jays, they are quite abundant on my property, as well as being resident at my nursery in town. I haven’t noticed any decline, especially as the walnuts get harvested. They follow the food sources.

  2. Tia Will


    I am not sure of your intent with this statement. In any area of science that is not firmly established, this is how the process works. Studies are made, reported, criticized sometimes by the authors themselves if being honest, sometimes by others.
    In areas of ongoing investigation, lack of questioning and inquiry would mean lack of progress even if that progress is frequently messy and frustrating especially in determining optimal public policy with limited and conflicting information.

  3. Anon

    Vector control attempts to use every means possible short of aerial spraying to rid our district (Sac and Yolo County) of the mosquito larvae. When the number of mosquitoes and birds testing positive for West Nile reaches a certain threshold despite all more benign efforts, that is when Vector Control makes the decision to aerial spray. Currently, Yolo County and all of CA are seeing a resurgence of West Nile, despite the drought. Vector Control thinks the drought may actually worsen the situation, as both birds and mosquitoes congregate more at the few remaining water sites. The compromise solution reached by the City Council was to invite all the citizens who are upset about the aerial spraying to become volunteers to try to eradicate the mosquito larvae so that aerial spraying would not be necessary. Should be an interesting experiment. But if the volunteers cannot address the problem, the state will address it with aerial spraying for public health safety reasons. West Nile is a very serious and debilitating disease, and two new species of mosquitoes have invaded CA, that carry dengue and some other disease I cannot remember the name of (chikangoyou?).

    1. Don Shor

      Another question I have, in case either of the subcommittee members are reading this (I’d be happy to help develop a list of questions), is whether the ‘hot spots’ for larvae development are primarily in agricultural or residential areas. Are the traps in sufficient numbers, and appropriately distributed, to assess where the mosquitoes are primarily coming from? If it’s ag land, sloughs, irrigation ditches, stock ponds, etc., then that’s where the resources should be directed. If it’s residential areas, then education and volunteer monitoring may be effective.

      1. Robb Davis

        Don – I will be taking you up on your offer. The answer, without going into detail is that there are important breeding areas in both agricultural and residential areas. I have more to learn about the specifics of breeding of the two (I believe) mosquito species in question but it appears that they can lay eggs in very small bodies of water like might be found in backyards. This makes environmental control a challenge at the larval stage.

        I should note that I think the work of the sub-committee and a community-based program in Davis has several outcomes: 1) learning more about what exactly we are up against in terms of vector control. This is all the more important because other species of mosquitos, carrying other debilitating diseases (yellow fever, chikungunya (sp?) and dengue), are now found in CA and we need to be vigilant to assure they do not get established here. 2) extending public education, via “peer” educators/neighbors on home-based vector control and personal protection and 3) extending vector control district staff efforts, be they breeding site identification, actual control efforts (placing larvacide, fish, etc.) or data collection.

      2. Anon

        To Don: Vector Control addresses both residential and agricultural breeding grounds for mosquitoes. Obviously open fields with trenches of water for irrigating will invite mosquitoes, as will wetlands habitat. Those are taken care of with larval pesticides and fish that eat the larvae, among other techniques. Residential ponds are also treated much the same way. However, the problem comes in with folks who leave standing water in back yards, from irrigating their lawns and shrubbery, pet water dishes, kiddie pools, etc. They need to be educated to empty the standing water regularly, and if possible not have it out at all. This is where the “volunteers” may come in – to knock on doors, and perhaps remind people to not leave standing water out for mosquitoes to breed in.

  4. DurantFan

    Why have the organic gardening, farming, and produce communities been so silent on the impacts of the spraying on their products? The lack of response or concern from the Co-op, Farmers Market, and the Buy Local(ly) folks (among others) seem to indicate that the label “organic” may be based more of rhetoric than result.

    1. BrianRiley429

      Is that true? Do they have carte blanche to spray over any farmer’s field whatsoever — including those fields that grow certified organic (CCOF) produce? I have a hard time believing that they could do that.

    1. Frankly

      I know this will drift a bit off topic, but I think it is still connected.

      Wheat intolerance and Celiac Disease has increased 400 percent in the last 30-40 years. And this number is controlled for changes in diagnostic techniques, so it is pretty reliable. I have it. 25% of my employees have it.

      Current science is pointing to hybridization as being the culprit. Not GMO per say, but the old methods of natural cross-breading and those using chemical mutation devices that caused shorter-stocked plants with huge heads of bug and fungus-resistant grain.

      In addition to changes in the gluten protein molecule, there is a ubiquitous little chemical in wheat known as ‘wheat germ agglutinin’ (WGA) which is largely responsible for many of wheat’s pervasive ill effects. Researchers are now discovering that WGA in modern wheat is very different from the per-hybridization grains. The WGA issue is a larger “lectin problem”. It remains almost entirely obscured. Lectins, though found in all grains, seeds, legumes, dairy and even the tomato and potato, are rarely discussed in connection with health or illness, even when their presence in our diet may greatly reduce both the quality and length of our lives. Lectins have changed as we have modified our farmed food away from their heirloom character.

      In addition, there are new theories and discoveries linking viruses and bacteria to other human diseases like cancer. For example, a food born bacteria that causes a temporary digestive malady might also be the source of future cancer of the digestive system… or colitis or other serious inflammatory bowel disease.

      Lastly, as we have seen lately with the EV-D68 virus weeping the Midwest, the Ebola outbreak in Africa… and thousands of other viral diseases that can explode… West Nile is not something to dismiss.

      The point I am making here is that the concern over very mild and small doses of aerial pesticide spraying should be considered in the larger picture of what are a large array of risks to our health that connect to our food supply and our insect supply.

      1. Robin W.

        I am not following your logic. There is a serious Ebola outbreak in Africa, so therefore we should be very concerned about West Nile virus?

        The problem with the scorched earth approach of the Vector Control District is that they do not feel any need to do a balancing test where they would look at the potential long-term harms to the local population (human and, to a lesser degree, animal) due to West Nile Virus and balance them against the long- term potential harms to the local population (human and, to a lesser degree, animal) due to spraying with these toxins. The harms that need to be considered include toxic run-off in water and due to seepage into the food supply. Harm to children, the elderly and people at special risk (eg, with allergies or respiratory problems) needs to be considered.

        The only thing that Vector Control ever seems to consider is the incidence of the West Nile Virus itself – often only in animals, as my understanding is that we have had no human cases in Yolo this year – rather than looking at the incidence of morbidity caused by the virus, and without ever looking at the potential long- term harms due to the spraying. No balancing test done at all.

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