Beyond Pesticides/National Coalition Against the Misuse of Pesticides
701 E Street, SE, Washington DC 20003
202-543-5450 (voice), 202-543-4791 (fax)
[email protected] www.beyondpesticides.org

Beyond Pesticides/National Coalition Against the Misuse of Pesticides

Beyond Pesticides/National Coalition Against the Misuse of Pesticides (NCAMP) is a national environmental organization, based in Washington, DC, with members all 50 states, which advocates for public protection from pesticides and promotes safer pest management practices.

As local spraying for adult mosquitoes begins throughout the Eastern U.S. for West Nile Virus (WNV), it must be recognized that these spray programs are of limited efficacy. That is, spraying does not appear to be an effective way to prevent death or illness associated with insect-borne West Nile Virus. A large part of this has to do with understanding the life cycle of mosquitoes and their biology. Another large part of this has to do with the inability, especially in an urban environment, to hit target insects with typical ground spraying from trucks or by aerial application.

While recognizing the public health threat of WNV and given limited pesticide spray efficacy, it becomes even more important to recognize the public health hazards associated with widespread pesticide exposure. Synthetic pyrethroids, used widely by across the country, are neurotoxic and have been linked to cancer. Children with respiratory problems, such as asthma, are particularly vulnerable to these pesticides and will suffer disproportionately from exposure.

While the many communities have moved in the right direction and in many cases resisted spraying upon finding dead infected birds, communities must reassess the real efficacy of spraying for adult mosquito control in the context of pesticide risks, especially for children whose respiratory systems are already weakened.


The Centers of Disease Control and Prevention (CDC) state that spraying adulticides, pesticides intended to kill adult mosquitoes, is usually the least efficient mosquito control technique. Aside from adverse health effects posed to humans, adulticiding may actually increase the number of mosquitoes by destroying their natural predators . Additionally, mosquitoes that survive the spraying may become resistant, longer-lived, more aggressive, and have an increased prevalence of the virus within their bodies . Despite these problems, adulticides are often used in the battle to control mosquitoes.

Synthetic Pyrethroids

Synthetic pyrethroids, which include resmethrin (Scourge) and sumithrin (Anvil), are adulticides patterned after pyrethrum, an extract from the chrysanthemum flower. While similar to pyrethrum, synthetic pyrethroids have been chemically engineered to have greater toxicity and longer breakdown times . Additionally, almost all synthetic pyrethroid mosquito products are combined with synergists, which increase potency and compromise the human body's ability to detoxify the pesticide. Symptoms of exposure include: dermatitis and asthma-like reactions, nasal stuffiness, headache, nausea, incoordination, tremors, convulsions, facial flushing and swelling, and burning and itching sensations . Synthetic pyrethroids are endocrine disruptors and have been linked to breast cancer . Deaths due to exposure have resulted from to respiratory failure. People with asthma and pollen allergies should be especially cautious. Breakdown times range from a few hours in direct sunlight, to several months in damp, dark environments.


Organophosphates, which include malathion (Fyfanon), naled (Dibrom) and chlorpyrifos (Mosquitomist), are a highly toxic class of pesticides that affect the central nervous, cardiovascular and respiratory systems. Symptoms of exposure include: numbness, tingling sensations, headache, dizziness, tremors, nausea, abdominal cramps, sweating, incoordination, blurred vision, difficulty breathing, slow heartbeat, unconsciousness, incontinence, convulsions and fatality . Some organophosphates have been linked to birth defects and cancer. Breakdown times range from a few days in direct sunlight, to several months in damp, dark environments.


Communities must aggressively deliver the following message:

  • Habitiat Modification - To get rid of mosquitoes, get rid of their breeding sites. Because mosquitoes do not travel far from where they hatch, you can continue to have a dramatic impact on local mosquito populations throughout the biting season by cleaning up standing water on your property. Get rid of unnecessary debris on your property; empty water from toys, buckets, birdbaths, swimming pool covers and any other areas water may be collecting; drill holes in the bottom of recycling bins and other containers that must be kept outside; and, clean out rain gutters and make sure that they are draining properly.
  • Avoiding the Bite - First, wear more clothes in the evening when mosquitoes are most active. If you are going outside, put on a hat and wear long sleeves and pants. If you choose to use insect repellents, use should avoid products that contain DEET (N,N-diethyl-meta-toluamide), especially when choosing a product for children. Several cases of DEET poisonings have been reported by EPA, including three fatalities. Products containing geraniol (MosquitoSafe), citronella (Natrapel), or a combination of soybean, geranium and coconut oils (Bite Blocker) are safer, effective mosquito repellents, but may need to be reapplied throughout the day.

The following programs must be put in place in order to protect public health.

  • Public Education - West Nile virus prevention begins with a strong public education program. Community officials must educate the public on how to reduce the chance of mosquito bites through the elimination of breeding habitats and the proper use of repellents (see above).
  • Surveillance - Tracking larval and adult mosquito populations, species types, breeding locations and virus outbreaks is an essential part of any mosquito management program. Knowing when and where the virus is likely strike allows for precise, targeted control techniques.
  • Habitat Modification - As on personal property, community land should be cleared of all standing water that could serve as potential breeding habitat (see above).
  • Larviciding - Because not all breeding sites can be eliminated, it is a good idea to use larvicides, particularly products containing B.t.i. (Bacillus thuringiensis var. israelensis), in places such as storm drains and sewer treatment plants. B.t.i. is proven to be effective and is virtually non-toxic to humans. Methoprene (Altosid) is an endocrine disruptor, has been linked to wildlife deformities and should not be used. Aside from traditional larvicides, biological controls, like mosquito-feeding fish of the Gambia genus, have been used nationwide with great success. To avoid ecological problems, these fish should only be used in enclosed bodies of water.

Precautionary Measures

Communities have a duty to warn the public about the dangers of pesticides, while providing information on ways to minimize exposure to dangerous pesticides. Communities should embrace and utilize the following guidelines:

  • Notify public at least 72 hours in advance. Utilize the media and/or send notices to every household, school, hospital, and business in the community to tell them when the spraying will occur so they will have ample time to protect themselves. Alert the public that pesticides are not safe.
  • Provide public with precautionary measures. Everyone should receive guidelines on how to reduce exposure to pesticides.
  • Monitor public for adverse health effects. Set up a hotline for receiving reports, collecting hospital records, and requiring physician reporting of incidents.
  • Monitor pesticide levels in the environment. Use wipe tests of outdoor and indoor surfaces, check air conditioner filters, evaluate water samples, and conduct soil and food residue tests from gardens and farms.
  • Advise hospitals and schools. Also notify other buildings with especially vulnerable populations to take extra precautionary measures to prevent pesticides from entering buildings.

Communities should notify the public of ways to "Protect Yourself from Pesticide Exposure!"

Leave the area (Infants, children, pregnant women, the elderly, and individuals with compromised immune systems should take extra care to avoid pesticide exposure.)

  • Close the windows
  • Turn off air intake on air conditioners
  • Take toys and lawn furniture inside
  • Remove shoes before entering homes to avoid tracking in residues
  • Cover swimming pools
  • Do not let children play near or behind truck-mounted applicators

The critical point that continues to be lost on city officials in the management of West Nile Virus is that pesticides are poisons. Because they are poisons, officials are charged with ensuring that laws, specifically intended to protect the public and the environment, are not violated.

We understand that people are concerned about the West Nile Virus. We also know that people are concerned about the widescale spraying of pesticides and the associated public health and environmental hazards. It makes no sense to spray for adult mosquitoes if the spray program does not offer adequate controls and the use of the pesticides presents a greater risk than the target disease.

Thank you.

Mosquito Life Cycle

In the United States, West Nile Virus (WNV) is primarily associated with the Culex mosquitoes. Within this genus, three species, namely C. pipiens, C. restuans, and C. salinarius make up the majority of those mosquitoes found to be infected with WNV. Only female mosquitoes take blood meals, the male's only purpose is to provide sperm and they usually die one or two days after emerging as adults. In contrast, the adult females may live 2-4 weeks or more, depending on climate, species, predation, and a host of other factors.

All mosquitoes go through a complicated life cycle called "complete metamorphosis." Complete metamorphosis involves four distinct stages - egg, larva, pupa, and adult. The length of time that each stage lasts depends on a number of variables with temperature having the greatest impact.

Eggs are laid in "rafts" on standing bodies of water. The eggs require one to two days in water before hatching into 1st instar larvae.

Larvae, or wigglers, develop as four instars. They molt three times during ten to twelve days before pupating.

Pupae, or tumblers, metamorphose over one to two days into adults.

Adults emerge from their pupal cases approximately twelve to sixteen days after being laid as eggs by their mother.

After mating, the female requires a blood meal in order to produce over 250 eggs. It takes her three to four days to digest the blood and produce the eggs. Females transmit diseases when they live long enough to spread infection from the first blood meal victim to the second blood meal victim. Only a very small percentage of females live this long. Culex mosquitoes are generally weak fliers and do not move far from their larval habitat, although they have been known to fly up to two miles.