Washington, D.C. does not spray adulticides.

    Officials in our nation's capital decided not to spray adulticides “for many reasons.” These include scientific research that demonstrates that adulticiding is not effective, as well as concerns over health risks to people.  We quote from the plan for 2004:

“Adulticiding only kills mosquitoes that are flying and remains effective for only a few hours.  The efficacy of adulticiding is open for debate and is not considered an effective tool for mosquito management or control through only one application, or, over time, as shown through scientific research.  Reapplications of adulticide may compound negative health effects of pesticide usage.”   (Emphasis ours)

“Washington, DC has the highest asthma rate in the country (2.5 times the national average).  Aerosolized pesticides can trigger asthma and aggravate respiratory conditions . . .  Broadcast aerosol applications of pesticides, even at night, will elicit a negative public response.”  (Emphasis ours)

    Are people, particularly those responsible for spraying pesticides, aware of the fact that the California Department Of Health Services estimated the number of people in 2003 in Yolo County with asthma at 23,000 (17,000 adults and 6,000 children), for example?  If even a small percentage of these people were negatively impacted by adulticides it would be a significant number.  Again, from the D.C. plan:

“The District does not expect to spray for mosquitoes because of low efficacy; kills of non-target species and potential health risks to a high population of persons affected with respiratory problems and compromised immune systems.”

“When we find West Nile present in mosquito pools here in Washington, D.C., we don't spray,” said Peggy Keller, chief of the Bureau of Community Hygiene and Animal Disease Prevention in the D.C. Department of Health.

“We've learned that the best way to protect the public from both the virus and the pesticides is to intensify our larval program and distribute outreach and education information that emphasizes prevention and protection techniques to the public in the surrounding area.

    Read more about the District's model in achieving a positive community response and protecting all citizens.  Also, a July 30, 2007, article from the Washington Post reports that in that area: "Five years ago, West Nile virus seemed like a major public health threat to the Washington region, with nearly 100 human cases and 11 deaths. But the disease has receded rapidly here since then, even as it remains a problem elsewhere in the United States.  Health experts credit the region's relatively low toll since then to a well-coordinated response from local agencies that included raising public awareness about prevention and applying larvicide to storm drains and other target areas."  The virus is receding into chronic endemicity: "the virus seems to be stabilized . . . it is endemic in our area."

    When we pointed out the great D.C. success in controlling WNv with larvacides, water management, and public education, without spraying adulticides, District Manager David Brown inexplicably changed his position on which mosquito species demanded that we spray in this region and argued that D.C. officials have an easier time of things, whereas exactly the opposite is true -- according to our entomologist we lack several potent vectors that the East coast has to contend with such as Aedes solicitans, that are much more likely to transmit to people than either of the main suspected vectors here, Culex tarsalis or Culex pipiens.  But more importantly, our climate is hostile to the transmission of this arbovirus where the more humid climate of D.C. promotes it.  This has to do with the relatively low survivorship of mosquitoes in arid and semi-arid habitats such as ours, and the length of time required for the incubation of the virus in the mosquitoes. Only one in a thousand will live long enough to transmit the disease in our climatic conditions.