Thursday, July 2, 2015

Neem in the G**den






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…

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