Daily News Archive

Mosquito Spraying Continues Despite Health Hazards and Ineffectiveness
(Beyond Pesticides, July 6, 2004)
San Bernadino County, in southern California has been spraying pesticides in the hopes of combating West Nile Virus. Last week, workers sprayed pesticides aimed at killing adult mosquitoes in a neighborhood where a few contracted the virus, according to ABC news. Jackie Rigby said she believes that she and her sons contracted the virus during a Mother's Day camping trip in a neighboring county. "I don't think my neighborhood is the problem, but I don't know," she said. "I can't even recall seeing any mosquitoes here recently."

Although West Nile Virus is a public health threat, the spraying of pesticides is also a potential health hazard. Moreover, mosquito spraying is also not very effective. A raft of evidence shows that adulticiding (killing mosquitoes in their adult stage) is not effective for controlling mosquito populations, and that the risks to human health, wildlife and water quality posed by exposure to pesticides likely outweigh the potential benefits of such a spray program.

Beyond Pesticides has been working on this issue since 1999, and has just come out with The Truth About Mosquitoes, Pesticides and West Nile virus, a Beyond Pesticides factsheet. Along with over 20 other groups, the organization formed the National Alliance for Informed Mosquito Management (AIMM). The mission of AIMM is to protect the public and the environment from unnecessary exposure to hazardous pesticides used in the attempt to control mosquito-borne diseases. By working with communities, experts, and public officials, the Alliance informs the public about the hazards of mosquito pesticides and calls for the adoption of safer, least-toxic methods of managing mosquitoes and the threat of West Nile virus (WNV).

The Centers for Disease Control and Prevention (CDC) states that spraying adulticides is usually the least efficient mosquito control technique. There are a few main reasons that adulticiding is not effective. First, mosquitoes are tiny, and fogging neighborhoods or spraying pesticides out of planes is an extremely inefficient way to kill them. According to Dr. David Pimentel, an entomologist at Cornell University, 0.1% of sprayed pesticides actually hit the target pest. Second, adulticiding programs target mosquitoes at the wrong stage. Such programs do not get at the mosquitoes until after they have matured and are biting, and do not restrict mosquitoes from continuing to breed. After Hurricane Andrew caused a surge in mosquito populations in Florida, state officials took bite counts before and after widespread aerial spraying, and found that mosquito populations surged back to pre-spray levels within three days of the treatment.

Adult WNV-carrying mosquitoes can also develop resistance to insecticides. Furthermore, broad-spectrum insecticides will kill all flying insects they contact, including mosquito predators such as dragonflies, leaving populations with fewer natural controls. While traditional adulticide methods look like action, in actuality they accomplish very little.

Moreover, these pesticides pose unacceptable health risks. According to the New York City Department of Health, in 2000, more people were reported to have gotten sick from pesticide spraying than from exposure to West Nile Virus: 157 people reported illness as a result of exposure to pesticides used for mosquito control, while only 19 people were hospitalized for WNV. The pesticides most commonly used across the country are neurotoxic and have been linked to cancer and other illnesses. People with compromised immune systems, chemically sensitive people, pregnant women, and children with respiratory problems such as asthma are particularly vulnerable to these pesticides and will suffer disproportionately from exposure.

Fortunately, there are more effective alternatives available for mosquito control. Many communities around the US have moved away from broadcast spraying of adulticides to find more effective mosquito management practices that pose fewer risks to human health, wildlife, and water quality. These communities are adopting preventive strategies that manage mosquito breeding areas and educate people to use non-toxic insect repellents. The City of Lyndhurst, Ohio, a suburb of Cleveland, passed a landmark ordinance last season prohibiting the spraying of pesticides “in an effort to help control the spread of the West Nile virus.” (Daily News) Other communities, such as Ft. Worth, Texas, and Washington, DC also have no-spray policies.

One of the main approaches to combating West Nile Virus without the use of pesticides is targeting mosquitoes in the larval stage. Larval control of mosquitoes is the most effective means of controlling mosquito populations according to the CDC and other mosquito control experts and can be done a number of ways without the broadcast use of pesticides that may endanger wildlife.

Take Action: Contact your local officials or your local newspapers about the hazards of pesticides, and urge them to investigate options other than pesticide spraying for combating West Nile Virus in your community. Click here for sample letters to the editor and letters to policy makers, and to learn about alternatives to pesticide spraying.