Bohart and Washino's 1978 Mosquitoes of California includes several maps
showing that in the course of 15 years (from 1960 to 1975) mosquito
resistance to organophosphates spread enormously in California's Central
Valley.
It is hard for an exterminated insect population to evolve pesticide
resistance. It is easy to evolve resistance in most other cases.
As for Sacrameto-Yolo West Nile spraying:
The Sacramento-Yolo Mosquito Abatement District carefully avoided a
public discussion of their spraying in Davis, the home of UCDavis, until
after their very dubious spraying strategy was already decided. When
they did attempt to conduct a no-public-discussion "informational"
meeting to a room full of scientists, they were met with a good deal of
scorn. Very little serious epidemiological work has gone into the
spraying plans.
Patrick Foley
[EMAIL PROTECTED]
Paul Cherubini wrote:
> Last year Sacramento, California county health officials
> conducted repeated aerial spraying over parts
> of the city and suburbs to substantially reduce the population
> of West Nile Virus vectoring mosquitoes:
> http://i85.photobucket.com/albums/k75/4af/wn.jpg The article
> says the officials even planned the aerial spraying two years in
> advance because they know that alternatives to chemical
> insecticide spraying are only marginally effective at controlling
> mosquitoes.
>
> Citizen groups http://www.stopwestnilesprayingnow.org/
> protested the spraying using they types of arguments we have
> heard from the anti-DDT camp. Example: they said:
> http://www.stopwestnilesprayingnow.org/Risk.htm one
> ingredient in the spray, piperonyl butoxide, "has been shown
> to induce DNA damage in several different assays for genotoxicity
> and also to function as an endocrine disruptor."
>
> Nevertheless, Sacramento public health officials determined
> the public health benefits of the aerial spraying far outweighed
> the public health risks from exposure to chemical spray.
> Sacramento officials have also said they are prepared to
> aerial spray chemical insecticides again over Sacramento this
> summer if necessary.
>
> In less affluent, tropical nations where malaria is prevalent,
> aerial spraying with pyrethroid insecticides is not an
> affordable option. The other limitation of pyrethroids is
> that indoor wall treatments are only fractionally as effective
> as DDT at killing and repelling mosquitoes for long
> stretches of time (6-12 months).
>
> The amount of DDT necessary to treat the interior walls of
> a huge number of homes is many orders of magnitude smaller
> than amount needed to treat a large acreage of crops. So, for
> example, if criminals or corrupt regulatory officials diverted
> a shipment of DDT wettable powder that was intended to
> treat 450,000 homes and potentially save many thousands
> of lives, it would only be enough DDT to treat 1000 acres
> (1.4 square miles) of a crop like cotton. Thus, there could
> not be any serious envionmental consequences if some
> of the DDT that was manufactured for home use was
> occasionally diverted for crop use. Also, among the
> countries that have already started using DDT indoors
> again, I have not heard of any reports of widespread
> criminal activity or corruption with regard to it's use.
>
> With regard to the argument "what happens when the
> mosquitoes become resistant", well resistance has not
> been a major problem in structural pest control. For example,
> food processing plants and food storage warehouses
> in the USA have been using fogging machines to create
> a San Francisco like fog inside their buildings once every week
> or month for several consecutive decades using the same
> chemical (pyrethroid or organophosphate) insecticides
> without serious resistance problems:
>
> Example of a California grocery distribution center
> warehouse:
> http://i85.photobucket.com/albums/k75/4af/groca.jpg
> http://i85.photobucket.com/albums/k75/4af/grob.jpg
>
> Paul Cherubini
> El Dorado, Calif.
>
>
