'Killer spices' provide eco-friendly pesticides for organic fruits and veggiesAugust 17, 2009
In a study presented here today 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, the researcher says.
"We are exploring the potential use of natural pesticides based on plant essential oils - commonly used in foods and beverages as flavorings," says study presenter Murray Isman, Ph.D., 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, the researcher says.
"These products expand the limited arsenal of organic growers to combat pests," explains Isman. "They're still only a small piece of the insecticide market, but they're growing and gaining momentum."
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 - Isman says. They're also safer for farm workers, who are at high risk for pesticide exposure, he notes.
But 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, Isman says. Researchers are now seeking ways of making the natural pesticides longer-lasting and more potent, he notes.
"They're not a panacea for pest control," cautions Isman. Conventional pesticides are still the most effective way to control caterpillars, grasshoppers, beetles and other large insects on commercial food crops, he 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."
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. Unlike 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, Isman notes.
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.
Other scientists are currently exploring the insect-fighting potential of lavender, basil, bergamot, patchouli oil, and at least a dozen other oils from exotic plant sources in China. Funding for this study was provided by EcoSMART®, a botanical pesticide company based in Alpharetta, Ga.
American Chemical Society
Related Pesticides Current Events and Pesticides News Articles
Banana plant fights off crop's invisible nemesis: roundworms
The banana variety Yangambi km5 produces toxic substances that kill the nematode Radopholus similis, a roundworm that infects the root tissue of banana plants - to the frustration of farmers worldwide.
Entomologists update definitions to tackle resistance to biotech crops and pesticides
Resistance to pesticides has now been recorded in nearly a thousand pest species, including more than 500 insects, 218 weeds, and 190 fungi that attack plants.
Researchers trap moths with plant-produced sex pheromone
A collaborative experiment involving a Kansas State University biochemist may mark the beginning of an effective, environmentally friendly plant-based method of insect control.
Characterization of stink bug saliva proteins opens door to controlling pests
Brown marmorated stink bugs cause millions of dollars in crop losses across the United States because of the damage their saliva does to plant tissues.
Toxic injection with elastic band
Bacteria have developed many different ways of smuggling their toxic cargo into cells.
How safe is the enemy of a citrus-threatening pest?
The Asian citrus psyllid (ACP) can spread the lethal and incurable citrus disease known as huanglongbing (HLB) or citrus greening that threatens the multi-billion dollar global citrus industry.
Tighter economic regulation needed to reverse obesity epidemic -- study
Governments could slow - and even reverse - the growing epidemic of obesity by taking measures to counter fast food consumption, according to a study published in the Bulletin of the World Health Organization today.
Common crop pesticides kill honeybee larvae in the hive
Four pesticides commonly used on crops to kill insects and fungi also kill honeybee larvae within their hives, according to Penn State and University of Florida researchers.
Exposure to pesticides results in smaller worker bees
Exposure to a widely used pesticide causes worker bumblebees to grow less and then hatch out at a smaller size, according to a new study by Royal Holloway University of London.
Loss of biodiversity limits toxin degradation
You might not think of microbes when you consider biodiversity, but it turns out that even a moderate loss of less than 5% of soil microbes may compromise some key ecosystem functions and could lead to lower degradation of toxins in the environment.
More Pesticides Current Events and Pesticides News Articles