Spices like rosemary, thyme, clove, and mint can provide eco-friendly pesticides for organic fruits and vegetables, determine scientists in a new study.
As the industry tries to satisfy demands for fruits and veggies among the growing portion of consumers, well-known spices are now becoming organic agriculture's key weapons against insect pests.
In a study presented at the American Chemical Society's 238th National Meeting, scientists in Canada are reporting exciting new research on these so-called "essential oil pesticides" or "killer spices."
These substances represent a relatively new class of natural insecticides that show promise as an environmentally friendly alternative to conventional pesticides while also posing less risk to human and animal health.
"We are exploring the potential use of natural pesticides based on plant essential oils - commonly used in foods and beverages as flavorings," said study presenter Murray Isman, of the University of British Columbia.
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.
Over the past decade, Isman and colleagues tested many plant essential oils and found that they have a broad range of insecticidal activity against agricultural pests.
Some spiced-based commercial products now being used by farmers have already shown success in protecting organic strawberry, spinach, and tomato crops against destructive aphids and mites.
"These products expand the limited arsenal of organic growers to combat pests," explained Isman. "They're still only a small piece of the insecticide market, but they're growing and gaining momentum," he added.
The natural pesticides have several advantages.
Unlike conventional pesticides, these "killer spices" do not require extensive regulatory approval and are readily available.
An additional advantage is that insects are less likely to evolve resistance - the ability to shrug off once-effective toxins.
They are also safer for farm workers, who are at high risk for pesticide exposure.
The "killer spices" aren't just limited to agricultural use. Some show promise in the home as eco-friendly toxins and repellents against mosquitoes, flies, and roaches.
nlike conventional bug sprays, which have a harsh odor, these natural pesticides tend to have a pleasant, spicy aroma.
Many contain the same oils that are used in aromatherapy products, including cinnamon and peppermint, according to Isman.
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, which cause food poisoning.