(Beyond Pesticides, January 21, 2011) Further proof of the ineffectiveness of chemical pest control has emerged in the form of a study from The Ohio State University documenting the growing resistance of bed bugs to pesticide treatments. The study shows that modern bed bugs have developed the ability to defend themselves against pyrethroid pesticides, due in part to the widespread use of such treatment methods. These findings highlight the need for widespread adoption of alternative, non-chemical methods for controlling bed bugs and other insect pests. The study, which was published in the journal PLoS ONE, is entitled “Transcriptomics of the Bed Bug (Cimex lectularius).”
The researchers found that the bugs developed the ability to produce certain enzymes, which can break down toxic chemicals, at higher levels of than previous generations. These enzymes allow the chemicals to be easily excreted by the insects without being harmed. When comparing modern bugs to a colony that has existed in isolation for several decades — without any exposure to pesticides — the team found strong evidence of resistance. Bugs from the isolated colony were readily killed when exposed to even small amounts of pyrethroids. However, the modern bugs, which have been exposed to pesticide treatments for decades, required a dosage of as much as 1,000 times the amount that should normally be lethal.
Pest resistance is essentially “nothing more than sped-up evolution,” according to toxicologist John Clark, Ph.D., who was quoted in the Wall Street Journal. When chemicals are applied as a pest control, there are often at least a small number of organisms that survive the treatment due to stronger immune systems or some other genetic abnormality. Since these bugs are the only ones left to procreate, their offspring will also inherit these genes, and the process will continue, until the entire population has evolved to resist the effects of a certain chemical. This process is sped up even further when pesticides are applied over and over in large quantities, as pyrethroids have been in attempts to eradicate bed bugs.
Bed bugs have had a resurgence in the U.S. in recent years, which is believed to be caused in part by increasingly widespread pesticide resistance. This has led to public anxiety about the pests and drastic attempts to stem their spread through various means, often including the use of highly toxic and harmful chemicals. For example, the State of Ohio, dealing with infestation in several major cities in 2009, petitioned the U.S. Environmental Protection Agency (EPA) to approve the indoor use of the pesticide propoxur. The agency considers propoxur to be a probable carcinogen and, due to concerns posed to children, banned it for in-home use in 2007. About 25 other states supported Ohio’s request for an emergency exemption. In comments to the agency objecting to the petition for propoxur, Beyond Pesticides and other environmental and public health advocates urged the agency to reject the request, citing numerous serious public health threats associated with the chemical, as well as the availability of alternatives. EPA rejected Ohio’s petition in June.
Pyrethroids, some of the most common chemicals used in attempts to treat bed bug infestations, are a class of pesticides that are synthetic versions of pyrethrin, a natural insecticide found in certain species of chrysanthemum. They were initially introduced on the market as ”˜safer’ alternatives to the heavily regulated and highly toxic organophosphates such as chlorpyrifos and diazinon, which were banned for residential use in 2001 and 2004, respectively. Despite the fact that there are plenty of effective pest control methods that are not nearly as toxic, pyrethroids are now some of the most popular household pesticides. They are cause for concern to consumers because of their link to serious chronic health problems. Synthetic pyrethroids are suspected endocrine disruptors, and have been found lingering in the dust at daycare centers.
Not only are chemical treatments often more harmful than bed bugs, they are also not actually necessary, as these pests can be effectively controlled with non-toxic approaches. An Integrative Pest Management (IPM) approach, which includes methods such as vacuuming, steaming, and exposing the bugs to high heat can control an infestation without dangerous side effects. This approach, as well as taking steps such as sealing cracks and crevices, reducing clutter and encasing mattresses can also help to prevent an infestation in the first place. Beyond Pesticides has put together a bed bug web page which includes a detailed fact sheet discussing bed bugs, the problems with pesticide treatments, and alternative control methods.
In less than two weeks, on February 1-2, 2011, EPA will be holding its Second National Bedbug Summit in Washington, DC. The aim of the summit is to gain input from scientists, medical professionals, pest control operators, and the general public as to how best to confront the growing bed bug problem. More information on the summit, which is free to attend, is available on EPA’s website.
Additionally, alternative solutions to problems associated with the use of pesticides, including insect resistance will be among many topics covered at Beyond Pesticides’ 29th annual National Pesticide Forum to be held in Denver, CO in April, 2011. Sustainable Community: Practical solutions for health and the environment is hosted by Beyond Pesticides, the Colorado School of Public Health — Department of Environmental and Occupational Health, Mountain and Plains Education and Research Center, and the Denver Beekeeping Association. The conference will focus on the links between pesticides, health and the environment and will include sessions on the latest pesticide science and links to specific diseases, impacts on pollinators, organic food and farming, pesticide-free land care and much more. Read about the keynote speakers and find other information, including how to register, at www.beyondpesticides.org/forum.