Tell me about Neem

What are its uses, how well does it work and can you use it on vegetables?
Any info appreciated.

hiya Cottage_Rose,

Where to start?

Neem is derived from the Neem tree that is a sacred plant in India, Pakistan and neighboring countries. One of the reasons most skeletons in anatomy classes around the world are Indian is because they normally have all of their teeth. The bark of the Neem tree is rubbed on the gums to prevent diseases of the gums and mouth. It has worked for centuries, and having a Neem tree on your property is a sign of wealth and good fortune.

Now for the pest control aspects. The compound extracted from the Neem tree seed is called Azadirachtin (the genus is Azadirachta). Azadirachtin has both insecticidal and fungicidal/ bacteriacidal activities when applied to plants. It is listed for a number of plants including edible crops when the correct formulation for edible crops is used. Azadirachtin also works as an insect repellant in that most visiting type insects (grasshoppers, beetles) can smell the material and know that it is harmful to them. It is hypothesized that there is some genetic alteration that happens to pest insects that come in contact with this material causing sterility or infertile eggs. Neem is listed for most ornamentals and has become rather a standard for rosarians recently. Neem is listed for activity and control of hundreds of insect pests as well as several common pathogenic fungi, namely mildews, rust, black spot.,etc...

This is an important botanical pesticide used by many gardeners/ farmers with an eye on the larger picture of the garden/ farm as an ecosystem onto itself instead of focusing on a single pest. There are volumes written on Neem and one need only to Google the word Neem and even more mundane literature than this treatise is available...lol.

I swear by this stuff, and so do most of the organic farmers I know.

Best to you in your research,
Don

Well! I guess that about covers it! LOL Thanks!
Thats Neem sounds too good to be true...kills bugs and fungal diseases?!
WOW!
How does it work on those #!$%&*bleeeepin Japanese Beetles?
Sure would love to hear testimonies from anybody here that uses it.

hiya Cottage_Rose,

I've used Neem for a variety of pests for decades on four continents. Use this link to see a simple listing of pests controlled by this material.

http://www.groworganic.com

I've used in on everything from cereal grains to fruits to vegetable crops to ornamentals.

COOL! Thanks Don! :))

Might want to shop around first; not all products claiming to be Neem have effective amounts of azadirachtin. Can you recommend any specifically, DrDon?

I have found that here in the states one of the best is the pure Neem oil sold by DynaGro.

I quickly found this link to a DynaGro retailer. You'll need to scroll down to get to the Neem.

http://www.nehydro.com/Dyna-Gro.html

best,
Don

Thanks that was my next question.

I ordered some from the NEhydro.
How often do you spray to prevent fungal diseases?
Also if you spray it on fruits or vegetables how long do you have to wait before you can eat it?
Can Neem be mixed with liquid fertilizers such as Miracle Grow or Seaweed-fish emulsion?

hiya Cottage_Rose.

If you are using Seaweed as a foliar spray...go ahead and mix it with Neem. I would be wary of mixing it with high N materials like MG (I can't even type the brand name...lol) or fish emulsion.

Spray according to the directions on the packaging and as you would normally apply a fungicide, in the morning. As far as frequency of application, try it first and see how it works for you. It can be applied every week if necessary, however, it would probably be enough to use it every two weeks to every month. And there's a very good chance only a few treatments during your growing season will be needed.

I'd be grateful to hear about your experience with this material.

best,
Don

I understood (mistakenly?) that using neem regularly could cause sensitivity in some plants, and that it should be used to address problems rather than as a blanket preventative. Wrong?

I hate conflicting info...but thanks for bringing that up Zeppy.

Sorry Don...didn't mean to use the "MG" word. ;-)

Zeppy's right, that's why I suggested that you see how it works for you and how long it takes for a return of your problems with fungi. As I said, it may only be needed a couple of times during your entire growing season. We use this stuff as a "Big Gun" in our organic pest management programs, and it is only used as a second to last resort. Pyrethrins for insects is the last resort. For fungi, have you tried dilute compost tea? It has known antifungal properties and is easy to make, blends well with most foliar fertilizers....even the blue crystals...arrrgh...lol.

If you are serious about going a little more natural with your rose care program, there are volumes of data on the topic. Also remember that your typical lime-sulphur fungicides are organic approved for the most part, as are some (not all) bordeaux mixtures.

The use of Neem, as Zeppy suggests, is for blowing away the competition, and it has, as I suggested earlier, some DNA reprocussions. Use with care and use sparingly. Over here, we are very strictly organic and only use pest/vector killers when our competitive organisms get too far behind. And then in a very gradual escalation.

best to you,
Don

Greeeat...I bought a giant jug of Neem concentrate which will probably last me a life time. ;-p
Don you will be happy to know I mainly use Espoma Rose Tone, Neptunes Harvest (fish and seaweed) or Saltwater Farms Sea Rose (fish/seaweed) and POOP.
I raise chickens and now as you know geese... "poop factories" :)
Now I have never heard of using compost tea as an antifungal!
Have you heard of the Cornell Formula (antifungal)?
Its baking soda, light horticulture oil, dash of dish soap.
Or how about spraying with milk?
I've tried them all but none seem that effective. But then again I probably don't spray enough.
We have horribley humid summers and blackspot & powdery mildew is a major problem, not to mention Rose Chafers and now the dreaded Japanese Beetles.
(I think I'm a glutton for punishment)

P.S.
good grief...what are the problems with too much Neem or sensitivity's/ DNA repercussions???

Oh, you know. Plants develop walking appendages, reactive brains, and start exacting revenge for our bad gardening decisions. :)

No, really, I'd like to know what the DNA business is too. I thought it was just a case of sensitivity in a given plant; didn't know it would carry on to the seeds.

I'm not so much worried about seeds vs. damage to the plant and what it does to edibles.

There are a few documented cases where excessive overuse of the Azadirachta has made for infertile or otherwise sterile seeds in some ornamentals. There are no documented cases of Neem being harmful to food crops where the kernels or immature seeds are what is harvested.

I've used the milk thing and the Cornell recipe with baking soda is very good also. Compost tea is so rich in hygienic micro organisms that they out compete and are actually known to consume the pathogenic organisms that are fungal diseases on occasion. The process/ system of 'Competitive Exclusion' is what is actually active in compost tea sprays. The good guys crowd out the bad ones and throw them under the bus.

rotf Zeppy.....sentient Celery, that's just what we need....lol. I would think that Rutabagas would be the first to gain consciousness if only to complain about why they are called Rutabagas. We grow some every year just so I can use the word in a sentence now and then....lol. Oh yeah, and the Beta Carotene.

Question; If two sentient Rhubarbs get into a fight in a bar, is it still called a Rhubarb? Or since humans get into Rhubarbs in bars would rhubarbs get into humans?

I'm not an expert but have been following this thread with interest because of my horrible bug infestation last year. You name it and I had it in my garden. I just ordered some neem oil to try this year and wanted to be sure it would be safe for pets and the plants. I did a lot of research today and feel pretty good about using it now.

Some pretty informative articles here:

http://www.ipmofalaska.com/files/neem.html

http://www.wisegeek.com/what-is-neem-oil.htm

Looks like it's completely safe for edibles, couldn't find anything at all regarding seeds. I'm sure drdon knows more.

hiya arachide,

Those are both fabulous links, thanks for sharing them. In many years of using this material I've yet to experience any case where residues caused damage to edibles or made them inedible. And I still haven't seen any broccoli playing baseball in the garden...lol.

You got me started on the whole research thing, drdon. Thanks. It was interesting and fun to do. "The essence of teaching is to make learning contagious. . ."

Wellllll, I'm relieved we're not talking about gene alteration. Drdon, take that rhubarb question straight to the koan forum. Deeeeeeeeep. My squash plant and I have no idea.

Well I "Neemed" half my roses this evening and will do the rest tomorrow if its not raining. BTW how long does it have to dry on the leaf before the rain doesn't wash it off? Its way humid here. I doubt it will dry tonight. If it rained would I have to re-apply it? So heres hoping it works since the *bleep* Rose Chafers are out in full force humping on & eating my roses. Oh and lucky us when the RC are done with their breeding cycle the Japanese Beetles show up and are here until FALL!
GRRRR!!!
Keeping my fingers crossed that it will work as an antifungal too.
I have some definate disease magnets that will let me know if its working or not.
The smell of the Neem reminded me of that copper or sulfur whatever it is spray for black spot and mildew.



This message was edited Jun 13, 2005 10:59 PM

If Neem tastes "bitter" which repels bugs how come you can use it on vegetables that you eat without if leaving a bitter taste on it?

I don't think it stays on so long, but it does more than just repel, so it's helping break the life cycle of some pests.

And I'd give anything from the garden a quick rinse before eating it anyway. So many dousings with fish emulsion... urgh.

May yr buggies bite the dust.

Azadirachtin, the effective ingrediant in Neem oil, is very similar in structure to a class of hormones called ecdysones that regulate the processes of molting and metamorphosis in many insects. In the case of azadirachtin, it works as an inhibitor to molting and metamorphosis. The common Western Bracken (Pteridium aquilinum), a fern that many on DG might be familiar with, is interesting in this context, as it produces a number of different ecdysones (actual ecdysones, as opposed to Azadirachtin, which mimics the function of ecdysones) naturally which deter and/or kill many of the insects that target it. In the case of the bracken, it speeds up the development/molting processes of the insects, resulting in fatally abnormal growth cycles. Currently in Britain, and probably in the US though I am not aware of anything specific, there is research going on as to how people might utilize the bracken as a source of insecticidal mulch or spray. So keep your eyes peeled over the next few years for some new natural insecticides with similarly safe properties and action to complement Neem oil.

gregr18, I am awash in admiration.

I wonder, since it's so effective on soft-bodied bugs, whether there are possibilities for mosquito control from neem... o please lord...

Say WHAT???
I feel so blond.

Zeppy, Unfortunately, I don't think that Neem is terribly effective at disrupting the growth cycle of mosquitoes since the growth hormones that govern their development are a bit different than those that Neem oil targets. Methoprene, which is considered non-toxic to humans, works through a very similar process on mosquitoes since it does effectively mimic their growth hormones, but some of the components of methoprene's breakdown (called retinoids) also mimic growth hormones in many aquatic creatures like frogs, hence the 6 legged frogs that pop up in areas in which methoprene is used :( Some people use Neem as a mosquito repellent, but as far as controlling their populations, I think research on it is looking in other directions.

Zeppy, Don't feel blonde! Ecdysis is just the more technical term for molting. It comes from the Greek word for stripping or taking something off. So, ecdysone = ecdysis + hormone, and is a broad name given to a broad class of compounds that regulate molting in insects, snakes, and crustaceans. Neem is great because it specifically targets these compounds without other complications that can arise when you start to fool Mother Nature (see the reference to methoprene I made above). I referred to ecdysones in case anyone in the thread wanted to research them directly, because some good stuff is going on with their applied use, but they are complex and could make anyone feel blonde. :) Neem away, though! It's great stuff.

Don't go calling zeppy blond...I'm the blond one. ;-)

All the fancy talk about ecdysones and I can't even get names straight. I'd say I'm the blondest of the bunch now! And to boot, I accidentally started a thread with this same response! Quite a mess of the Organic Gardening forum I'm making. Sorry folks, I'll learn someday. :)

great info, thanks!

Hi Zeppy, drdon, Cottage_Rose, and gregr18-
I was just researching Neem for the upcoming growing season and found this thread. Great info!

Do any of you have updates or results from your "experiments" with Neem?
Any news on the Western Bracken fern?

Thanks!!

As I recall it clogged up my sprayer and I didn't follow through.
Story of my gardening life :(
Maybe this year.
Is Dr. Don still here?

Hi, thought I'd jump into this resurrected thread with a hint about pump sprayers. If you mix the neem with a drop or two of emulsifier (a "spreader-sticker" in farmer terms) you won't have so much clogging. Using a couple of drops of plain dish detergent (not the "anti bacterial" kind) will work, as well.

You need to shake the mix often as you spray. You can also help things mix by using warm water. Neem tends to solidify when cool, like fine olive oil.

When you're done, unscrew the trigger/tube from the bottle. Dip the tube in some clean water and spray the clean water through until any residual oil mix is out of the entire system. You can put some detergent in the water to scrub out all traces of oil.

Also, everything I've read about Neem says to not store it mixed-- use it within eight hours or so. Now I don't know why this is so, because neem oil has a pretty long shelf life, if stored dark, cool, and airtight. Perhaps some of this forum's experts can answer this question.

Here's my two cents on neem. It works excellently on ornamentals to prevent blackspot and powdery mildew. But it won't "cure" an outbreak once it has started. It is strictly a preventative.

Neem is one of the "big guns" in the organic pest control regime-- if you want to avoid killing beneficials, use it when insects are not present. And use it very selectively. I only use it on plants that are disease magnets-- like roses and phlox. I use it on the tomatoes only in the early season, before the flowers form.

There is apparently some research done by the Rodale Institute that shows promise for neem as a systemic fungicide. That is, it enters plant cells and, in effect, innoculates the plant agains fungal disease. However, I can't find the research on which this claim was based. I read it in a Rodale book on organic pest control. Experts?

Does it work for iris-borers? That is my big problem this year.