'Killer Spices' Help Organic Farmers Achieve Natural Pest Control

Murray Isman Plant Pesticides photo
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Murray Isman, Ph.D., of the University of British Columbia, is developing essential oil pesticides to offer better pest control on organic farms. Photo by Martin Dee, University of British Columbia, via the American Chemical Society.

Some delicious herbs and spices may be the key to natural pest control on organic farms, according to researchers at the University of British Columbia in Vancouver, Canada.

Dubbed "killer spices" and "essential oil pesticides" by researchers, the essential oils of clove, mint, rosemary and thyme can be mixed together several different ways and diluted in water to create a spray that either detracts or kills pest insects, but is safe for farmers to handle and consumers to ingest. The study, presented by Murray Isman, PhD, last week at the American Chemical Society's 238th National Meeting, is the culmination of a decade of research, that has led to the successful development of some products, according to a EurekaAlert release. Spice-based products are already being used on organic strawberry, spinach and tomato crops, says Isman, adding:

These products expand the limited arsenal of organic growers to combat pests. They're still only a small piece of the insecticide market, but they're growing and gaining momentum.

'Killer Spices' Are Safer For Your Health
Aside from keeping chemicals out of the soil, these "essential oil pesticides" offer several benefits. They're all-natural and made with edible plants, so they're safer to work with than chemical pesticides and consumers won't be ingesting chemicals (though there's no word on whether it harms other vulnerable wildlife, such as frogs). Only a very small amount of the oils are used and the raw materials are readily available or easy to grow, so it's not a drain on precious resources. Another significant benefit, says Isman, is these essential oil pesticides won't lose their effectiveness like chemical pesticides tend to.
Another big plus of this research, says Isman, is it can be applied to natural insect repellent formulas for humans. Instead of dousing yourself in foul-smelling bug spray (many of which contain DEET), these oils offer a natural insect repellent alternative that smells wonderful.

There's really only one drawback at the moment: The essential oils don't last very long. Not only do they evaporate quickly, they also degrade in the sun, so they need to be reapplied often to be effective, which is inefficient and a drain on precious water resources. This problem has researchers working on the next step--finding a way to make these alternatives long-lasting.