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Neem Oil in Alaska
Neem oil is a broad spectrum botanical
insecticide, miticide and fungicide treatment derived from the
seeds of the neem tree (Azadirachta indica). Neem trees are
native to South East Asia, and is grown in many countries
throughout the world, including India, Burma (Myanmar) and
Australia. It is also grown in the United States, mostly in
Florida as an ornamental shade tree, though its commercial
production for neem products is increasing in the U.S. The neem
tree is a botanical relative of mahogany. Neem tree products are
associated with many agricultural and medicinal uses. It is widely
relied on for herbal medicine in its native countries and is used
in many cosmetic and pharmaceutical products as well as pest
control in homes and crops.
The neem tree produces a compound called
azadirachtin which protects it from damaging insects. A zadirachtin
is a tetranortriterpenoid compound which influences the hormonal
system, feeding activity, reproduction and flying ability of
insects. Azadirachtin has low mammalian toxicity, it degrades
rapidly in the environment, and has low side effects on non-target
species and beneficial insects. Seeds of the neem tree contain the
highest concentration of azadirachtin. There are several products
registered in Alaska containing azadirachtin, including Azatin
XL®, Bioneem®, and Ornazin®.
Neem seed oil (NSO) is composed
of a complex mixture of biologically active compounds. When the
natural neem oil is removed from the seeds and treated with
alcohol, virtually all of the azadirachtin and related substances
separate from the oil itself. The remaining oil - without the
azadirachtin - is called Clarified Hydrophobic Extract of Neem
Oil. Commercial products containing this extract, such as Trilogy ®,
Triact®, Rose Defense®, and Greenlight® Fruit, Nut & Vegetable
Spray do not contain measurable amounts of azadirachtin and
contain an emulsifying agent, so are not pure neem oil and may not
be suitable for use on certified organic crops. Instead, use
expeller expressed, cold pressed or virgin neem oil, sometimes
called "raw" neem or "crude" neem oil.
More than a hundred terpenoid
compounds have been identified from different parts of the neem
tree. Azidirachtin is the most active of these. Several different
kinds of azadirachtin have been isolated, the most abundant of
which is Azadirachtin-A. In most traditional preparations of neem
as pesticide or medicine, a mixture of neem chemicals are present
and provide the active principles.
Mode of Action: Neem has
many main modes of action with the primary role of disrupting an
insect's metamorphosis. The principle active ingredient,
azadirachtin, acts as an insect growth regulator (IGR) preventing
exoskeleton development and impeding the molting process. It is
most effective on younger stages of an insects development than
when they have reached their adult form. Best control is achieved
when insect populations are light to moderate. There are more than
25 other active compounds found in neem, including meliantriol,
vepol, and salannin. It has a garlic like
odor, and an extremely bitter taste. Its extremely bitter flavor
can make many insects stop feeding on the host plant. Neem oil can
also suffocate mites, whiteflies, aphids and other types of soft
bodied insects on contact. These multiple modes of action make it
unlikely that insects and plant pathogens can develop resistance
to neem compounds.
Neem has both contact and
systemic action in many plants. When it is applied to soil as a
drench, some plant species absorb it through their roots and will
translocate it through the plant tissue.
As a fungicide neem is mainly
used as a preventative and when disease is just starting to show.
It coats the leaf surface which in turn prevents the germination
of the fungal spores. Neem oil and clarified hydrophobic extracts
of neem oil is effective against rots, mildews, rusts, scab,
leafspot and blights.
Application and Use: Neem
is used in both ornamental and food crops. Raw neem seed oil (not
extracts of neem oil) can be used mixed with water and an
emulsifying agent such as pure castille soap. One general purpose
application rate is to use neem oil at a 1% ratio to water with an
emulsifying agent or non-ionic spray adjuvant. Some commercial
products containing clarified hydrophobic extract of neem oil
contain a surfactant that accomplishes this emulsifying process.
Use raw neem seed oil at a ratio of 0.5% to 2.0% depending upon
the targeted use. Apply it as a foliar spray keeping it agitated
during application to keep it well mixed. It must be used within 8
hours after mixing with water. For other commercially prepared
products containing neem oil (usually 70% clarified hydrophobic
extract of neem) follow the manufacturers label rates and
precautions.
Neem has been used with success in Alaska for
aphids, cutworms, fungus gnats, shore flies, leaf-miners, thrips,
powdery mildew and many others. Various products containing neem
oil, clarified hydrophobic extract of neem, azidirachtin, and
other neem compounds are registered for use in Alaska. Pure neem
seed oil containing all of the active liminoid compounds is also
readily available in Alaska, however some of these pure neem
compounds are not labeled for pesticide use. One product
containing 100% neem oil is often sold in garden centers next to
the insecticides and fungicides implying it is recommended for use
as a pesticide, but it is only advertised by the manufacturer as
an organic leaf polish.
Products containing extracts of neem oil are
registered pesticides, tested and approved by the EPA for use as a
pesticide. Remember, extracts of neem have had the active
compounds found in neem oil removed during the refining process,
and these products usually contain alcohol or phenol used in the
extraction process. These extracts of neem have an emulsifier
added to help it mix readily with water. Pure or "crude" neem seed
oil must be mixed with an emulsifying agent to accomplish this.
Pure castille soap can be used as an emulsifier when using pure
neem seed oil. Warm water should be used when using crude neem oil
since it becomes solid at low temperatures.
Neem oil has also been used for
insects other than those that feed on plants. Spiders,
cockroaches, grain weevils, and other pests of homes and stored
food are reputed to be repelled, or killed by neem oil compounds.
Neem has been used for thousands of years to protect grain in its
native countries. It is often formulated into shampoo, creams,
lotions, and even toothpaste. It is useful as a natural remedy for
head lice, scabies, and as a mosquito and biting fly repellent.
Ecological effects: It is non
toxic to humans, birds, earthworms or animals. Being an oil it can
affect some beneficial insects if it is actually sprayed on them
so it is recommended to use it prior to releasing beneficials or
to conduct a trial to observe its effects on the organism prior to
large scale use. Once the spray has dried it will not hurt most
beneficial organisms, including lady beetles, lacewings, orius
bugs, and predatory mites.
Sources:
The Neem Tree. Ed. Schmutterer. The
Neem Foundation.
Horticultural oils: New summer uses
on ornamental plant pests. The IPM Practitioner.
Neem; Mode of action of compounds
present in extracts and formulations of Azadirachta indica
seeds....Colorado State University.
Common Sense Pest Control. Chapter
7: Inorganics, organics and botanicals. Olkowski, et al.
Trilogy®, and Triact® are trademarks of Certis USA., Columbia, MD
Bioneem® is a trademark of Woodstream Corporation, Lititz, PA
AzatinXL® is a registered trademark of Olympic Horticultural
Products. Alpharetta, GA
Ornazin® is a trademark of SePro Corp. Carmen, ID
Rose Defense® and Greenlight® Fruit, Nut & Vegetable Spray is a
trademark of the Greenlight Company, San Antonio, TX
Neem America
makes no claims about neem and its uses. This article should
only be used for informational purposes. |
