Articles on Holistic Orcharding

Pure Neem Oil

by Michael Phillips

The cold-pressed oil of
neem seeds contains over
100 active constituents.
Photo courtesy of
Plasma Power.

A whole plant medicine works in many synergistic ways precisely because of the wide range of compounds to be found in any herb. The nutrient rich seed oil pressed from the seeds of the Azadirachta indica tree (common throughout most of Africa and India) offers three areas of holistic intrigue for fruit tree growers:

• Secondary plant metabolites in neem stimulate an immune response to ward off fungal disease in the fruit tree.
• Azadirachtin compounds inhibit molting cycles of pest insects found on the tree.
• Fatty acid chains serve as "fungal food" for the soil food web and the oft-overlooked arboreal food web. A foliar nutritional boost accompanies as well.

Quality Aspects of Neem

The raw seed oil tastes bitter and smells garlicky, if not nutty at its freshest. More to the point, this herbal remedy contains vitamin E, essential amino acids, and secondary plant metabolites called terpenoids and isoflavanoids. The fatty compounds in neem (derived from palmitic, stearic, linoleic, and oleic acids primarily) contribute considerably to overall plant health, which in turn help the fruit tree to be that much more able to resist disease.

Most of neem's insect control properties are attributed solely to a single constituent. Azadirachtin interferes with ecdysone (the key insect molting hormone) and therefore prevents larvae and pupae from completing the molting process. Unlike chemical insecticides, azadirachtin works on the insect's hormonal system, not on the digestive or nervous system, and does not lead to development of resistance in future generations. Azadirachtin by itself has impact but better results can be obtained by using all the liminoid compounds in the whole plant medicine. A kind of synergistic effect is obtained whereby one component strengthens and increases the working of another. The azadirachtin content in pure neem oil should average 1800 parts per million (0.18%) when tested.

Stimulating the immune response of the
tree itself prevents fungal spores from
getting a devastating foothold.

Corporate Dilution

The neem-derived insecticides on the commercial marketplace (like Neemix and AzaDirect) are basically an alcohol extraction of azadirachtin. Emulsifiers, activators, and stabilizers are added to make the final product easier to apply and store. The oil fraction left behind by this process demonstrates a limited effect against disease, from whence come the so-called hydrophobic neem fungicides. These clarified oil products (like Trilogy) basically work due to the smothering effect of any oil formulation.

Fair Trade Source

Plasma Power in India buys neem seeds from dedicated sources in India that provide quality seed. The harvesters are paid a fair wage for work they can depend on year after year. The Ahimsa Alternative in Minnesota imports the cold-pressed neem oil for use in agriculture and herbal medicine. Arun is the brother in India who works with his sister Usha in Minnesota. . . I recommend this family highly for their commitment to fair trade practices for farmers on both sides of the transaction.

Pure neem oil works on three fronts, checking
disease and pest insects while at the same time
boosting plant health.

Suggested Use

I apply pure neem oil along with liquid fish at the week of quarter-inch green, pink, petal fall, and 7 to 10 days after that. This early season program addresses many orchard health fronts including the primary infection period of fungal diseases like scab and rust. The pace of the weather AND the overlap with other materials (like Surround kaolin clay) determine exact timing. I continue to use neem through the summer (but now with certain fermented herbal teas rather than liquid fish) on a 10 to 14 day schedule, again coinciding with any other specific spray needs. A late August spray on the later varieties finishes up the use of neem oil for the season here in northern New Hampshire.

Rates

All foliar neem applications are made at a 0.5% concentration. It's easy to overdo a hand wand application and then see leaf damage and perhaps some fruit russeting. Certain varieties seem extra-sensitive, particularly pears, particularly on hot days (above 80°F). A half-gallon of neem oil mixed with a quarter cup plus of soap emulsifier mixed into 100 gallons of water achieves a 0.5% concentration.

Neem can go on at a higher concentration when the ground beneath the tree and the trunk and branch structure are the primary recipient of the spray application. Times for this are early spring, during borer oviposition at the soil line, and fall. Little leaf tissue shows prior to quarter-inch green and it's generally quite cool, thus risk of phytotoxicity is low. Similarly, once leaves start to drop and bud scales again become exposed, the fall holistic spray won't damage foliar tissue. One gallon of neem oil mixed with a half cup of soap emulsifier mixed into 100 gallons of water achieves a 1% concentration.

Spray Pointers

Raw neem seed oil will be anything but easy to spray unless you know the tricks of the trade. Due to its high levels of natural vegetable fats, unadulterated neem becomes as thick as butter at temperatures below 60°F. Planning ahead is a must when it comes time to spray: Place the container in a warm room (but not directly in sunlight) for a day or two until the consistency reverts to a homogenous liquid. Placing semi-thawed neem into a pot of warm water on cool mornings may be a necessary as a final step the day of spraying. An emulsifying agent can be any biodegradable soap. This must first be mixed directly into the neem oil; on the order of one tablespoon of emulsifier per 6 oz. of neem oil. Pour this oil/soap blend into warm water in a five-gallon bucket and stir vigorously before adding this mixture to the spray tank and its full volume of cooler water. Applications made every 10-14 days should prove entirely helpful. Be sure to clean your sprayer lines immediately afterwards.

Cost

Keep the multi-purpose aspects of neem in mind when evaluating what sprays are most justified in your budget. An acre of fruit trees treated under the full holistic program (through the summer months) can require as much as 6-8 gallons of pure neem oil per season. The "four spring sprays" along with that decisive fall application require a minimum of 3 gallons of neem oil per acre per season. All depends on the array of challenges faced at individual sites!

The neem tree shares its gift of
health with our orchard trees.
Pretty cool, eh?

Supposition Alerts. . .
What Fun!

Supporting the arboreal food web and enhancing tree immune function involves more than just neem oil but this whole plant medicine is certainly at the center of the action. Scab control is impressive, and only using the absolute minimum applications of sulfur when primary infection risk is "beyond obvious" is downright healthy for the orchard ecosystem. And some years, given helpful weather patterns, it may not be necessary to use mineral fungicides at all to back up the holistic approach!

Neem applications made to the bark in early spring act somewhat like dormant oil in inhibiting egg hatch of soft-bodied insects like aphids and mites. Overwintering moth species in the larval and/or pupal stages are affected by these same trunk/ground sprays. Second generation moths are both repelled and suppressed by summer use of neem oil. Ground absorption, resulting from spraying to the point of runoff in a season long program, likely affects the larval and pupal stages of EAS, PC, and AMF as well. Population pressures are dropping in Lost Nation Orchard as a result of the ongoing use of pure neem.

Organic Orcharding Articles

• An Intelligent Paradigm
• My Apple Orchard by Laura Ingalls Wilder
• Holistic Core Values
• The Fungal Curve
• Priming the Pump
• Holistic Orchard Management  
• Holistic Spray Ingredients
• Pure Neem Oil
• The Kaolin Clay Strategy
• The Lepidoptera Complex
• Borer Insights
• Curculio Riffs
• Ramial Wood Chip Primer
• Pruning Precepts
• Seasonal Checklist for the Holistic Orchard
• Apple Grower Network Research Pages