Spices Used for
May Be Used As Potential Pesticides
shown at right, from the June 30, 1947 issue of Time magazine, became
an anachronistic artifact after publication of Rachel Carson's Silent
Spring, which documented the eco- and human health dangers of DDT.
While DDT has been banned in the U.S. and most developed countries,
it remains a critical ally against malaria in many afflicted countries,
where public health experts defend limited household use as the lesser
of two evils.
But few believe that it's wise to use potently toxic synthetic pesticides
unless they're proven essential to save lives or feed hungry people
... especially when effective alternatives are available.
(This, among other reasons, is why we favor organically grown fare
over conventional crops.)
Fortunately, new evidence review indicates that extracts from common
kitchen seasonings - and plant essences used in aromatherapy -could
become a serious alternative ally against insect pests.
Plant extracts as safer preservatives and pesticides
Its well-proven that extracts of herbs like rosemary, oregano,
and clove possess potent antibacterial powers against meat-spoilage
and food-poisoning bacteria (Fu Y et al. 2007; López P et al.
2007; Burt S. 2004).
And in two presentations at the recent American Chemical Society National
Meeting, scientists from Canada reported that their evidence review
supports the practicality ? within limits ? of using herb and spice
extracts as safe, eco-friendly alternatives to conventional petrochemical
pesticides (Isman MB 2009).
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, Ph.D., of the University of British
Columbia. (Sampson MT 2009)
(Rather than fats, the constituents of the misnamed extracts called
essential oils are pungent, non-oily compounds such as
ketones and aldehydes.)
The new pesticides blend tiny amounts of two to four different spice
extracts, diluted in water. Some kill insects outright, while others
Over the past decade, Isman and his colleagues have tested many plant
essential oils and found that they attack a broad range of agricultural
Some spiced-based commercial products now being used by farmers have
already shown success in protecting organic strawberry, s
pinach, and tomato crops against aphids and mites.
These products expand the limited arsenal of organic growers
to combat pests, explains Isman. Theyre still only
a small piece of the insecticide market, but theyre growing
and gaining momentum. (Sampson MT 2009)
The natural advantages
Unlike conventional pesticides, these are derived from foods already
approved as safe, and are readily available.
And pests are less likely to evolve resistance to these natural toxins,
thanks to the presence of diverse chemicals in each extract, versus
the single molecule found in most synthetic pesticides.
In fact, plants produce these chemicals to protect themselves against
insects, fungi, and bacteria.
Theyre also safer for farm workers, who are at high risk for
pesticide exposure and injury.
The natural disadvantages
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.
The greatest promise is seen for first-world organic farms, and for
farms in poor countries where regulatory burdens are lower.
Natural pesticides can be toxic. For example, rotenone is an approved
plant-derived pesticide used on many organic farms, although it kills
fish readily and can make people who ingest it sick.
But rotenone is much more toxic than most of the herb-spice extracts
under review, which are short-lived and do not harm birds, mammals,
or humans unless ingested in concentrations far higher than would
be encountered on crops.
And these natural pesticides are generally less potent than conventional
pesticides, so they also must be applied in higher concentrations.
Dr. Ismans team says that they and other researchers are seeking
ways to make the natural pesticides stronger against insects, and
more durable, to reduce the quantities needed and the number of applications.
Theyre not a panacea for pest control, cautions
Isman. But at the end of the day, it comes down to whats
good for the environment and whats good for human health.
(Sampson MT 2009)
Consumer uses for spice extracts
Some plant extracts show promise as eco-friendly home repellents against
mosquitoes, flies, and roaches.
Unlike conventional bug sprays, which have a harsh odor, these natural
pesticides tend to have a pleasant aroma, since many contain the same
oils used in aromatherapy products, such as cinnamon and peppermint.
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
? such as rosemary extract ? for use on fruits and vegetables to destroy
food poisoning microbes such as E. coli and Salmonella.
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.
While funding for this study was provided by EcoSMART®, a botanical
pesticide company, much of the research its authors reviewed was largely
funded by government or non-commercial grants.
consider organic whole foods from both plant and animal kingdoms
to be a major key to superior health. We also think it's terribly
important to eat fish at least twice a week to get the essential
fatty acids. Here at our house, we only eat wild Alaskan salmon
and other wild seafoods from our friends at Vital Choice. Click
here to visit Vital Choice Seafood.
Y, Isman MB, Paduraru PM, Nagabandi S, Nair R, Plettner E. Screening
of dialkoxybenzenes and disubstituted cyclopentene derivatives against
the cabbage looper, Trichoplusia ni, for the discovery of new feeding
and oviposition deterrents. J Agric Food Chem. 2007 Dec 12;55(25):10323-30.
Epub 2007 Nov 20.
*Burt S. Essential oils: their antibacterial properties and potential
applications in foods--a review. Int J Food Microbiol. 2004 Aug
*Fu Y, Zu Y, Chen L, Shi X, Wang Z, Sun S, Efferth T. Antimicrobial
activity of clove and rosemary essential oils alone and in combination.
Phytother Res. 2007 Oct;21(10):989-94.
*Isman MB. AGRO 24 Plant essential oils as repellents and/or deterrents
to agricultural pests. Sunday, August 16, 2009. The 238th ACS National
Meeting, Washington, DC. Accessed at http://oasys2.confex.com/acs/238nm/techprogram/P1287760.HTM
*Isman MB. AGRO 8 Opportunities for the use of plant essential oil-based
insecticides in organic agriculture. Sunday, August 16, 2009. The
238th ACS National Meeting, Washington, DC. Accessed at http://oasys2.confex.com/acs/238nm/techprogram/P1287760.HTM
*Isman MB. Botanical insecticides, deterrents, and repellents in
modern agriculture and an increasingly regulated world. Annu Rev
Entomol. 2006;51:45-66. Review.
*Isman MB. Botanical insecticides: for richer, for poorer. Pest
Manag Sci. 2008 Jan;64(1):8-11.
*López P, Sanchez C, Batlle R, Nerín C. Vapor-phase
activities of cinnamon, thyme, and oregano essential oils and key
constituents against foodborne microorganisms. J Agric Food Chem.
2007 May 30;55(11):4348-56. Epub 2007 May 8.
*Miresmailli S, Isman MB. Efficacy and persistence of rosemary oil
as an acaricide against twospotted spider mite (Acari: Tetranychidae)
on greenhouse tomato. J Econ Entomol. 2006 Dec;99(6):2015-23.
*Sampson MT. Killer spices provide eco-friendly pesticides
for organic fruits and veggies. August 16, 2009. The American Chemical
Society. Accessed at http://portal.acs.org/portal/PublicWebSite/pressroom/newsreleases/CNBP_022744
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