(Beyond Pesticides, April 21, 2011) Citing consumer’s growing aversion to the toxic chemical DEET and other harmful pesticides, researchers at the Centers for Disease Control and Prevention (CDC) are pushing to develop a new natural repellent and insecticide from the chemical nootkatone, found in grapefruits. Nootkatone is derived from the essential oils of plants, including grapefruit, vetiver grass and Alaskan yellow cedar. As an essential oil, it is highly volatile and evaporates quickly. This means that it doesn’t last very long and may need to be applied frequently. As a result, researchers are seeking ways to make it longer-lasting.
In one cooperative project by the CDC and the U.S. Department of Agriculture’s (USDA) Agricultural Research Service (ARS), entomologists Kirby Stafford, PhD and Robert Behle, PhD use lignin to encapsulate nootkatone in order to extend the chemical’s residual activity. The study, “Lignin + Nootkatone = Dead Ticks” published in the January 2011 issue of Agricultural Research magazine.
Researcher Marc Dolan, PhD of the CDC’s vector-borne infectious diseases laboratory in Fort Collins, Colorado stresses nootkatone’s safety: “If you’ve had a grapefruit, you’ve consumed some nootkatone,” he said to NPR’s Morning Edition.
“Essential oils [such as nootkatone] kill bugs and then break down and are no longer active,” Dr. Dolan told Morning Edition. “So you don’t get a lot of soil contamination. We don’t see groundwater contamination. And we don’t have a high impact on other nontarget insects that may come into the sprayed area, such as bees and butterflies.”
Whether new derivatives of nootkatone will actually be “safe” remains to be seen, however. Since researchers hope that nootkatone will be formulated to last longer, it will no longer be able to claim the benefits of having low-environmental persistence. Furthermore, this same argument for safety has been made for other “natural” chemicals, such as permethrin and its very toxic chemically synthesized derivative counterparts, synthetic pyrethroids.
Though nootkatone and its future synthetic counterpart may be considered to be less toxic than most synthetic pesticides, it is important to remember that as a chemical with insecticidal properties, there is still a potential to cause harm to human and environmental health. The best way to combat a pest problem is through an Integrated Pest Management (IPM) approach that focuses on prevention, monitoring, and control to eliminate or drastically reduce the use of only least-toxic pesticides. IPM does this by utilizing a variety of methods and techniques, including cultural, biological and structural strategies to control a multitude of pest problems. For more information on safer methods to protect yourself from insects and other pests, please visit Beyond Pesticides’ Alternative Fact Sheets page and Mosquito Management program page.