Neem Tree
I have always said that gardening is an exciting profession
and this week has been no exception. I have found out about a product called
neem oil. The oil comes from the Indian native Margosa Tree and is nicknamed
the “plant with a promise”. It promises to make my gardening more ‘underground’
as the product has been banned in all European countries and Canada. That
sounds a bit too exciting so to clarify, you can buy need oil in aromatherapy
shops but under no circumstances can it be sold or marketed as a gardening
product. So everything you read from now on is top secret and just between you
and me…OK?
The oil can be bought in America as a product and has 6%
neem content in the bottle. The other 94% are “other products” so it’s best to
get the 100% cold pressed type from India which is what I did.
About Neem
In ancient Vedas, the neem tree is referred to “Sarva Roga
Nirvarini” – one capable of curing every illness and ailments. Neem has been
used in India since thousands of years and is used extensively in many Ayurveda
medicines for its disease fighting properties.
Every part of the tree, branch, leaves, barks, fruits,
flowers and root are extremely beneficial as they contain azadirachtin compound
which gives neem its anti-bacterial, anti-fungal and anti-parasitic properties.
Besides its several health benefits, it
is also used in a variety of household products. Neem oil contains fatty acids
like oleic acid and linoleic acid which are beneficial for the skin. People eat
neem leaves to cleanse the blood and in India it is a very spiritual tree and worshipped.
About the Oil
Neem oil is a vegetable oil extracted from the fruits and
seeds of neem tree. The oil is light to dark brown in colour depending upon its
method of processing. It is very bitter in taste mainly because of its
triglycerides and triterpenoid compounds. It is used for several purposes: There are claims that neem can treat Eczema,
fungal infections, removes skin dryness, acne, aging, healthy hair, dandruff, lice,
dogs fleas, making medicines, diabetes, arthritis, digestive, cosmetics, insect
repellent, prevents mosquitos breeding, treating minor wounds, cleaning,
cleaning teeth with the sticks and of course the thing I can’t mention as it’s
banned… a pesticide.
In the G***en
How does it work as a pesticide? Neem oil has many complex
active ingredients. Rather than being simple poisons, those ingredients are
similar to the hormones that insects produce. Insects take up the neem oil
ingredients just like natural hormones. Neem enters the system and blocks the
real hormones from working properly. Insects "forget" to eat, to
mate, or they stop laying eggs. Some forget that they can fly. If eggs are
produced they don't hatch, or the larvae don't moult.
Insects that are too confused to eat or breed will not
survive. The population eventually plummets, and they disappear. The cycle is
broken. How precisely it works is difficult for scientists to find out. There
are too many different active substances in neem oil, and every insect species
reacts differently to neem insecticide. Only chewing and sucking insects are
affected.
Takes its time
But this is not something that happens overnight. People
spray neem oil as insecticide, and expect everything to die instantly, because
that's what they are used to from chemical poisons. Apparently it needs time to
work. It's a much smarter way to deal with insect pests than to just kill
everything. But it is also the presence, the mere hint of a smell of neem oil is
said to be enough to keep leaf eating insects away.
The subtlety of the hormonal effects, and the fact that they
may take days or weeks to manifest, makes people overlook them. If it’s instant
affects you are looking for you will be disappointed!
Neem oil breaks down very quickly, too. It is especially
susceptible to UV light. But neem oil is also a systemic insecticide. That
means you can pour it on the soil (not pure neem oil of course, you use a
dilution or extract) and the plants absorb it. They take it up into their
tissue, and it works from the inside.
Like real hormones, neem oil insecticide works at very low
concentrations, in the parts per million ranges. A little neem oil goes a long
way. This might be one of the reasons for it being banned as it can be overused
and the hormones could be disruptive to humans. There could be more political
reasons about the ban though.
Other Reasons?
Neem has been very lucrative and successful for the
pesticide industry. The European patent office granted a patent for antifungal
products in the US department of agriculture and a multinational agrochemical
corporation. The Indian government challenged this saying that the product has
been used in India for over 2 millennia. In 2000 the European Patent office
ruled in India’s favour and the subsequent appeal by the big corporation in
2005 where they tried to claim they found new ways to extract the oil. The tree
is now free from patent restriction which maybe a reason for why it's not more
widely used as one company couldn't control the production and products. It’s a
hard item to categorize as the tree has so many different parts to use and as a
garden pesticide, and household, medicinal ingredient, it will need treating
with care and consideration.
Application
In any country where it’s not banned it’s bees to spray early
in the morning, or late afternoon /evening. Once the spray has dried it does
not harm your bees, ladybirds, lacewings, predatory mites and wasps etc.
Remember though, you didn’t hear it from me…
