Imagine acre upon acres of fragrant rosemary, thyme, clove, and mint; Rather than a fabulous dinner waiting to happen, these familiar spices are quickly becoming organic agriculture’s key weapons against insect pests as the industry tries to satisfy demands for fruits and vegetables among the growing portion of consumers seeking naturally grown produce.
An environmentally-friendly alternative to conventional pesticides–while also posing less risk to human and animal health, study presenter Murray Isman, Ph.D., of the University of British Columbia says, “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.” These new pesticides are generally a mixture of tiny amounts of two to four different spices diluted in water. Some kill insects outright, while others repel them.
Natural pesticides have several advantages.
- Unlike conventional pesticides, these “killer spices” do not require extensive regulatory approval and are readily available.
- Insects are less likely to evolve resistance — the ability to shrug off once-effective toxins.
- They’re safer for farm workers, who are at high risk for pesticide exposure.
However, the new pesticides also have shortcomings.
- Since essential oils tend to evaporate quickly and degrade rapidly in sunlight, farmers need to apply the spice-based pesticides to crops more frequently than conventional pesticides. (Some last only a few hours, compared to days or even months for conventional pesticides.)
- As these natural pesticides are generally less potent than conventional pesticides, they also must be applied in higher concentrations to achieve acceptable levels of pest control. Researchers are now seeking ways of making the natural pesticides longer-lasting and more potent.
The “killer spices” also show promise in the home as eco-friendly toxins and repellents against mosquitoes, flies, and roaches. Unlike conventional bug sprays, which have a harsh odor, these natural pesticides tend to have a pleasant aroma.
Manufacturers have already developed spice-based products that can repel ticks and fleas on dogs and cats without harming the animals. Researchers are now exploring the use of other spice-based products for use on fruits and vegetables to destroy microbes, such as E. coil and Salmonella.
Conventional pesticides are still the most effective way to control caterpillars, grasshoppers, beetles and other large insects on commercial food crops, Isman says. “But at the end of the day, it comes down to what’s good for the environment and what’s good for human health.”
American Chemical Society (2009, August 18). ‘Killer Spices’ Provide Eco-friendly Pesticides For Organic Fruits And Veggies. ScienceDaily.