Neem Oil vs. Mycorrhizae

[Agent 47]

After doing some research I felt like Neem Oil would be a great product to fend off insects in ones outdoor garden. However, If one were to pride themselves on their mycorrhizal relationships, would they have to worry about using Neem oil?

I don't know if it's just for marketing reasons, but the product claims to also be a fungicide, which would be bad in an organic garden. I've read mixed reviews as to whether or not it is even a fungicide, let alone bad for the mycorrhizae. Could it also possibly affect your beneficial microbes?

That being said, if one wasn't concerned for their friendly fungi, would spraying the surface of the soil with diluted Neem oil be sufficient in deterring or stopping non-airborne insects like ants or caterpillars?


It's been making me think, one sure would hate to kill their myc in a war on insects. What do you guys think?

 

[VerdantGreen]

ive found it hard to find any definitive answers about neem used as a soil drench.

does it get absorbed by the roots and have a systemic effect? - would be good if it did but im not sure. as an oil i personally cant see how it could.

does it harm soil microbes or indeed mycorrhizae?
again some answers would be good...

anyone??

 

[Clackamas Coot]

ive found it hard to find any definitive answers about neem used as a soil drench.

does it get absorbed by the roots and have a systemic effect? - would be good if it did but im not sure. as an oil i personally cant see how it could.

does it harm soil microbes or indeed mycorrhizae?
again some answers would be good...

anyone??

VerdantGreen

In the 2nd edition of 'Teaming With Microbes' there is a chapter on mycorrhizae fungi. The photos used were supplied by Mycorrhizal Applications in Southern Oregon. They supply a number of companies with their raw product - Fox Farms, Roots Organic, et al.

I sent them an email a couple of hours ago asking this question. Obviously it will be early next week before I get a response. I'll post their answer when it arrives.

I went to the scientific search engine, Scirus, and entered the terms 'mycorrhizae' and 'neem' as well as the name of the active ingredient, 'Azadirachtin'

Nothing of substance came up other than 3 independent studies conducted in India on the use of mycorrhizae on neem trees. And results were pretty spectacular as far as the increase in oil levels as well as higher amounts of the myriad of other agents found in neem seeds.

Cornell University in NY has been a major center of studying horticulture in the US for over 75 years. Almost all of the potting soils manufactured are based on the 'Cornell Mix' - at any rate here's a review of neem seed products from Cornell University that you might find helpful and/or interesting.

CC

 

[Dignan]

How does he DO that? ^^^^

Coot rawks.

 

[Dr. D]

Neem oil is a fungicide thats why its so good at getting rid of athletes foot and other fungal infections...i cant see that it would affect your mycho system but i also wouldnt really use it as a drench, it is an oil after all..

 

[VerdantGreen]

thanks CC - ill check those out.

yes dig, the CC man rocks! - i wish we had a UK version of CC so i could take advantage of all the good cheep products he recommends

my interest in neem and soil is more general as i dont use myco on my indoor grows, i simply want to know if applying it to soil will compromise the herd and if it can have a systemic effect with the plants from being absorbed by roots.

VG

 

[mad librettist]

VG, you know the precautionary principle... Neem oil is a powerful fungicide, but at what dose? Also if it does not totally eradicate fungi, does it select for one or more types, thus creating potential for imbalance?

Kudos Clack for your diligence. Can't wait to hear back.

I agree with VG that systemic control via root absorption makes no sense. It's a plant not a sponge. If there is a bit of systemic control, it will probably come from foliar application. On the other hand I have used it as a soil drench and noticed no adverse effects.

 

[VerdantGreen]

being able to water your flowering plants with neem for mite control during flower (without having to spray the buds) would be priceless.

VG

 

[guest2012y]

I made a pretty severe neem oil solution the other day using roughly 2 tablespoons per gallon of water with a bit of silicone as a emulsifier. I drenched my problem plant that came to me loaded with root aphids and fungus gnats. The plant is fine and the population of pests has dropped. Not gone,but definitely diminished.

I have done this before with good results,experimenting on test plants to see if a high dose would kill them. On one that I tried to kill,it turned horribly yellow but recovered within a week nicely.
I suspect that if there is an effect on the fungi and micro organisms,that it isn't a total wipeout and they have enough strength in numbers to make a comeback in a relatively short period of time.

As far as it being a method of control against PM,mites and fungus gnats in my garden,it has been incredibly effective applied as a foliar spray at the rate of 1/4 to 1/2 teaspoon per quart with the silicone emulsifier added at equal amounts. Mr. Coot turned me on to this and I have come to trust his judgement. If I doubt things or peoples advice...I don't do it.
However,the root aphid thing is something unlike gnats,mites,or PM...they seem to shrug off whatever neem application I apply,recovering as well as the plant that was drenched.

 

[Clackamas Coot]

i also wouldnt really use it as a drench, it is an oil after all..

The use of neem seed oil, per se, is pretty much a western phenomenon. Neem oil is pressed primarily for HABA products, medicines (including birth control), food manufacturing, etc.

It's the neem seed meal (aka neem cake) that is used as a fertilizer and has been for several centuries. The neem seed cake is also used to make a soil drench to apply Azadirachtal to the root zone.

Neem extracts (not neem tinctures) are also sold for human and animal consumption. Neem extracts can be mixed with water an applied either as a soil soak or as a foliar application.

Most of the retail products contain Azadirachtal at 1,500 PPM. Many of the extracts are as high as 6,500 PPM so caution needs to be used when figuring out a mixing ratio.

As a fertilizer, neem cake is a very solid soil amendment. It's N-P-K is 5-1-1 and while the potassium level seems a bit low, it's the micro nutrients and trace elements that the cake/meal contains that is the important part.

To do some solid research on neem and to avoid blogs and idiotic prepositions like 'Well, we just can't be sure yet! Not just yet!' (translation: 'I'm too f*cking lazy to actually find out') - search engines like Organic ePrints and Scirus will bury a real researcher with peer-reviewed studies conducted around the world by scientists - not stoners.

Don't think that neem products are effective against PM? Fine - then show me the data that it is not effective. And don't send me to someone's blog like "ImGrowinDank.com" or the idiot in Vancouver, B.C. with the goofy videos either.

That's too stupid to do even for the pure entertainment value it often provides.

CC

 

[guest2012y]

On another note,the seed meal mix I acquired from a local fellow (neem seed meal included in the mix) that I incorporated in my soil mix of my last rotation are not problem pots.

 

[Clackamas Coot]

Heh.......................

There's also a solid level of crustacean meal in that mix (chitin) that is equally helpful for microbial life in a soil for a number of reasons.

 

[guest2012y]

Heh.......................

There's also a solid level of crustacean meal in that mix (chitin) that is equally helpful for microbial life in a soil for a number of reasons.

I'm thinking this is a win win situation for my mix and I need some more......I wonder if it's available for purchase soon?

 

[Clackamas Coot]

No - but it is available as a gift with the obligatory dim sum lunch at Wong Kings in SE Portland.

I don't charge for my fertilizer mixes. It costs me less than $.70 per lb. to mix up regardless. A free lunch is much more fair.

CC

 

[VerdantGreen]

capt. - for your root aphids how about carefully immersing the whole pot in water (+ neem perhaps) for like an hour or something - not enough to drown the plant but maybe enough to drown the aphids. maybe every 2 - 3 days for a week or so???

just a theory but you never know,

alternatively take a cutting or two and sling the plant - you dont want it spreading to the rest of the garden - especially as you like recycling your soil....

 

[guest2012y]

LMAO CC...you got it.

Sunday August 1st 2010 21:00 hours...I'll be driving a blue Cadillac Escalade license # DUM 1.
I'll be wearing a Chinese red and silver dragon jacket with dark Burt Reynolds type sunglasses,White Nike sweat pants with blue stripes,and reeking of neem and cannabis.

Blond hair,red eyes........pinhole burns in jacket.

 

[guest2012y]

capt. - for your root aphids how about carefully immersing the whole pot in water (+ neem perhaps) for like an hour or something - not enough to drown the plant but maybe enough to drown the aphids. maybe every 2 - 3 days for a week or so???

just a theory but you never know,

alternatively take a cutting or two and sling the plant - you dont want it spreading to the rest of the garden - especially as you like recycling your soil....

Good idea VG...I've been thinking along those lines for sure. I do not want to use the infected plants soil again. The spreading issue is a concern. I'm pretty on the ball with my neem spray schedule,and when I see an area with a couple aphids in it,I dose the region with a quart!

 

[VerdantGreen]

cool, the best i can find for systemic neem is this - appears that it might work

http://www.nysaes.cornell.edu/pp/resourceguide/mfs/08neem.php

Active neem constituents can be absorbed through plant roots and systemically move upward through the plant through xylem tissues (Gill and Lewis 1971, Larew 1988, Nisbet, et al. 1993, Osman and Port 1990). This works best when sufficient quantities are applied to the root zone. Systemic effects are much less apparent from foliar sprays. Different plant species also differ widely in their ability to have systemic effects from neem. Neem constituents last much longer within the plant than when sprayed on the leaves. However, over time they will be diluted by growth.

Neem’s systemic properties suggest that applying it to transplants just before planting to the field could be an effective and inexpensive way to control certain pests. Similarly, applying neem with relatively large amounts of water, in directed sprays over the rows of small seedlings, could be a very efficient method of application. In one study, neem applied through a drip irrigation system significantly reduced lettuce aphids on romaine by over 50% (Palumbo et al. 2001).

here is the original study but i can only get an abstract
http://www.springerlink.com/content/l264t5065w4m5r91/

Gill, J. S. and C. T. Lewis. 1971. Systemic action of an insect feeding deterrent.

VG

 

[guest2012y]

Thanks VG and CC for the goodies...got some reading to do.

 

[feral]

Neem oil is a fungicide thats why its so good at getting rid of athletes foot and other fungal infections...i cant see that it would affect your mycho system but i also wouldnt really use it as a drench, it is an oil after all..

seriously? I work in animal shelters where at times ringworm is present. This would be better than walking around putting athletes foot cream on your body to get rid of it.