Monday, August 13, 7:00 am
Why Aerial Spraying for Mosquitos is a Terrible Plan - by Gene Helmick-Richardson
As a licensed pest control operator in the metroplex for over 20 years and with a PhD in Entomology I think I can speak with some authority and knowledge on the proposed aerial spraying for mosquitoes to halt the spread of West Nile Virus in Dallas. For those of you who don't want to wade through the boring facts presented below, I oppose any widespread spraying of adulticides for mosquito control because it simply doesn't work. It is a waste of time and resources when we should be focused on scientifically proven strategies to control this problem. Now for the boring details.
First the problem.The CDC fact sheet on WNV ( CDC: West Nile Virus - What You Need To Know) explains that only 1 in 150 people who contract the disease develop serious illness and 4 out of 5 have no symptoms at all. Many reading this have been exposed already and don't even know it. Deaths are extremely rare and almost always are complicated by some underlying health problems. This is not a serious problem. Enough hysteria, please.
"Well, its not a problem unless you or your loved ones get this disease." True. It gets very personal. I don't want to get WNV either because I'm in one of those vulnerable groups (over 65). I demand that the government "Do something!" about this problem. But, what should they do?
As a taxpayer I want the biggest bang for my hard-earned buck. Since the days of DDT, the answer for any pest problem has been toxic chemicals. Many will remember the old hand-pumped sprayer that grandma sprayed around the house to kill mosquitoes. Now it is the aerosol cans from the grocery store. Targeted spraying for personal control is a personal choice, but follow directions and don't use them around me.
The real problem with dependence on toxic mosquito adulticides is that they treat only the symptom, not the problem. Dr. David Pimentel addresses this problem in his research in New York. He has an excellent article at: http:// www.stopwestnilesprayingnow.org /WNv&mosqctrl.pdf
So why then are our county officials and even the county medical society recommending this outmoded and unscientific approach? I really don't know. You see, they had a closed meeting and then came out to announce they were going to use aerial spraying. I would love to see or hear what went on there. (Continued below the link.)
Zach Thompson and his hard working crew had been going by the book to closely monitor WNV pools. They had been targeting hot spot neighborhoods with the traditional and largely ineffective use of Ultra Low Volume (ULV) truck mounted sprayers. He had been demanding proof that aerial spraying works in metropolitan areas to control WNV without endangering the population. Seems like a reasonable request for the man ultimately charged with keeping us healthy and safe.
Somewhat surprisingly, there are virtually no research studies on the actual efficacy of spraying adulticides for WNV control. The lone exception is the study done in Sacramento, California.
http://wwwnc.cdc.gov/eid/article/14/5/07-1347_article.htm This is the study that I assume the Dallas County Medical Association mentioned in their recommendation to start aerial spraying.
Both Dr. Pimentel and I have some serious questions concerning the conduct, analysis, and conclusions of this study. Some have even called it "fatally flawed". As an initial effort to justify the expense and risks of aerial spraying for control of WNV, it is a much needed and absolutely necessary first step. However, it is a very shaky justification for exposing us all to dangerous pesticides.
There are other things to consider when we talk of aerial spraying. Besides the proven ineffectiveness in solving the problem, the effect on honey bees, butterflies, and even beneficial predators like dragon flies is well documented. Dr. Pimentel states that to control a mosquito population you should have 90% control. Reports of control range from 42% to 93% depending on a number of factors. If you fail to get 90% control, then the remaining 10%+ of survivors can quickly rebuild the population to original levels. Sometimes, due to the absence of beneficial predators, you may get a resurgence to even higher levels.
So, what do we do? Politicians are charged to "do something" and fortunately the correct thing to do is well documented. It starts with controlling the breeding sites. All stagnant water pools in the area should be located and either drained, treated with larvacides, or populated with mosquito fish. Educational programs like NY's Fight the Bite program and similar out reach programs have proven effective in preventing exposure and limiting populations of mosquitoes.
The manpower and expense involved in such programs, which include stricter code enforcement, free distribution of larvacides, and even door-to-door visits by volunteers or trained staff are not very high when compared to the cost of aerial pesticide application. And besides, they actually work.
Finally, and much more seriously, we are facing the potential for much more deadly threats of tropical diseases. If you fear WNV, you will be terrified of dengue fever and other serious mosquito borne diseases that are headed our way. If we empty our quiver on this mild threat we will be unarmed when a real threat arrives. Pesticide resistance is well-studied in mosquito populations. We will be creating "super mosquitoes" resistant to current pesticides.
For these and other reasons I feel that the use of aerial spraying in the Dallas metroplex is an unwise, ineffective, potentially dangerous, politically motivated over-reaction to a very mild threat. The decision was based on faulty research and may be counter productive at worst and a waste of limited resources at best.
Tell your government officials to stop now, before they poison your back yard.
Update
Dr. Gene Helmick-Richardson interview with ABC.
