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Old 12-03-2007, 01:43 PM
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Neem oil warning

I will never use neem oil again (hydrophobic extract, the commonest thing available around here). I have noted that nurseries and home centers are storing their neem oil OUTSIDE. I have been on the internet to check on storage temps. Of 5 products checked, 3 state minimum storage temp is 55 F and one says 38 F. I don't know about your particular weather, but I would guess that most places go below 55 F during winter. My neck of the woods gets to 13 F every winter or lower, and no one brings the neem oil inside for winter. Don't know what this does to the character of the oil, but it can't be good or they would not list the minimum at 55 F. How about the temperature in warehouses? Or in the process of trucking it around the country?

I have had no end of trouble with this stuff. Mottled leaves in Catts and Dens, death and disfigurement in terete leaved orchids, and now I am suspicious that the micro fungus in Phals is due to neem oil or other refined oils. The last time I used neem on mites this fall, it had no effect on them, and mites are not supposed to develop resistance to neem. If the manufactures can not insist on minimum temps from factory to point of sales, then I think this stuff is a disaster waiting to happen.

Those of you using pure neem oil may want to check the internet for the min temps on that stuff.
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Old 12-03-2007, 02:28 PM
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Did you dilute your solution well enough?
I've used it with great results. On just about everything in my yard from orchids to hibiscuses to gardenias...
Great for whackin' scale to black mold...

~LCA.
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Old 12-03-2007, 05:46 PM
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Cynthia, I believe the minimum is suggested because the neem becomes solid at colder temps, have not heard of it affecting the product. What I read or was told was to use warm water to 'thaw' it out (placing the neem container in the water). Someone even suggested refrigerating it, then sitting out at room temp. to warm it up for use. I believe it takes on a shortening like consistency. I think that I read somewhere that cold is okay, but that heat is very bad for neem. To get the oil from the seeds without losing integrity of the product, it is cold pressed. I would not buy it if it were sitting outside in hot weather, but cold should not be a problem (but it also depends on how many months it was sitting out). I order mine online from a guy that keeps it in his basement. It is Dyna Gro, and it is in a white bottle, because light also affects the integrity of the neem.

I have been using the pure neem on my Dend. an experiment of sorts. I use the pure neem on one, and my cinnamon mix on the other. They both had mites. What I am seeing is they are both fine with no mites, the one sprayed with neem is producing a new growth. I admit that I completely stopped using the stuff that is premixed in the green spray bottle, I wonder if the problem with the stuff was caused by heat during shiping? Caused a mottled leaf on 2 of my Gratixara, and almost killed my Onc. it is still in recovery, and I have doubts that it will even make it. Had a few mottled leaves on the Dend. but they have fallen off. I also believe that particular spray killed one of my Phals. it was fine one day, and the next I touched a leaf and the whole plant fell apart. I certainly will not use it again. I am holding off on judgement on the pure neem for now, but I am only using it on one plant, and it is a Dend., and nothing seems to faze the two that I have.

My best advice to anyone wanting to try neem is to buy pure neem being careful that you research the manufacturer (to see if how the neem is extracted from the seed, cold pressed is best), dilute the pure carefully and according to the directions, and to use on plants that have thicker leaves. Some of us here are still experimenting with it, and it has not always had the best results. I don't mind using it on a couple NOIDs to see if I can get some experience that may be helpful to others, however, I will not be horribly upset if it does do these plants in. I would not use it on my favorite unless I am positive that it will not do more harm than good.

Anyone else have some experience with using the pure neem oil?
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Old 12-03-2007, 11:27 PM
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I've been using neem oil for about a month or so now on my compot of Catts. They seem to be doing fine until recently.

Like brookn, I, too, read to store pure neem in cool place or the fridge to keep its potency. To soften/liquify, let stand in room temp. or place container in warm water.

In addition to what brook posted, when making a neem oil mix (neem/soap detergent/h2O) spray, only make the amount needed and use within 6 hours. Leftover mix should be discarded.

The last week or so, I've been lazy making a new neem oil mix for spraying my compot and have been using the same mix for a little over a week. Recently, I noticed the leaves of the seedlings are starting to shrivel and some are starting to mottle. That said, I'll be making a new mix at next spraying....and the next...
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Old 12-03-2007, 11:43 PM
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Please, Arlene, can you clarify what a "compot" is? Thank you
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Old 12-04-2007, 12:07 AM
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A compot is a community pot, generally seedlings from flask planted together into the same pot, and grown together until they are big enough to separate.

Compot=Community pot
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Old 12-04-2007, 02:08 PM
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Well, I think all my problems may be due to the hydrophobic extract. I am wondering if it has a shelf life/temp sensitivity/other weakness that results in a degradation similar to the problem mentioned by Arlene with storing the mixed solution. I have a 1000 plants and I absolutely can't handle the 'occasional' failure of the product and resulting damage. With this many plants, the damage adds up fast. For mites, I am now using the Bayer Advanced 3 in 1. Seems to work well, without any damage, but it will probably not be until next spring before I know how really effective this stuff is, as the mite problem with the cold weather seems to have abated. I know this is true outside, where the source of reinfection is coming from, but I would expect any mites inside the GH to be happily forging ahead, and I have not seen any since spraying with the B A 3 in 1. I have sort of sprayed twice (first spray missed a few usually uninfected plants, ran out of time, and second one was thorough), but am having trouble getting the product in Prescott, AZ. Am in talks with Lowe's about including this in their regular stock.
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Old 12-04-2007, 06:46 PM
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After doing a bunch of reading and research I think I might just steer clear of neem oil altogether. It just doesn't seem to be worth the trouble. When I inherited that Catt I bought the B A 3 in 1 and I think it works great. It's good for other ailments as well. But I only use it as a last resort. Mainly I stick to Brookn's recipe, worm tea, and Physan. I can understand your ordeal though Cynthia. You have to nip any problem quickly, especially with over 1000 plants. How do you keep track?
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Old 12-04-2007, 06:58 PM
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I have used several different kinds of Neem oil on over 700 plants multiple times over several years and I have not seen any problems.
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Old 12-04-2007, 09:07 PM
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I think Cynthia is absolutely right. I knew neem oil should not be exposed to light or heat. Because the active principle, azadirechtin, resembles a hormone. After reading Cynthia's thread I looked it up, biochemically speaking, and , of course the light/heat will render it ineffective by breaking up the highly oxidised parts ( hydroxyl and ketone ) of the molecule. I am sure light will disintegrate (reduction) the molecule, changing it so that the targeted organisms will not 'substitute' it in their metabolism.

I buy my Neem oil, dark and unsightly, in brown 75 ml bottles. If I open the cap one could smell the oil from about 3-4 metres.

linda shel: I use neem oil too. I even apply it right on the leaf with cotton swab. So far I have not had any problems except for the stench that lingers on a for a few hours..
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Old 12-05-2007, 12:29 AM
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Linda, how varied is your collection? Any terete leaved plants like the Papilionanthes, particularly vandarum, and Schoenorchis juncifolia? My vandarum, originally a big bushy plant, is now 4/5ths dead and very weak after several treatments with neem, not recognizing the problem as I went. I've killed 2 juncifolias so far, and the third one is being watched very carefully for signs of adverse reaction to any chemicals I use.

It may well be that I am getting mistreated neem from my suppliers. Can't think of any other reason for the string of problems I've had. But I am not the only orchid grower up here in Prescott that is convinced the neem is causing the mottled leaves.
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Old 12-05-2007, 03:23 AM
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I used Neem a lot when I lived in the US. Because my collection was largely housed in a sun room (part fo my apartment ) I didn't want to unleash chemicals in my breathing space. I used Neem at a concentration of about 1 tablespoon with about 1 tablespoon of dish soap to about 1 quart/litre of water. I used it only on my thick-leaved plants like Cattleyas and typically used it for soft bodied insects like mealies. I had good results with this method and my plants experienced no visibly detrimental effects form the oil.
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Old 12-05-2007, 01:00 PM
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Sounds like you started with the pure Neem. All my problems have been with the hydrophobic extract.
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Old 12-05-2007, 06:42 PM
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My collection if vary varied, but I do have a lot of Phals and Dendrobiums. I did have some problems with a couple of my Paphiopedilums, but not like you describe and believe that was from other causes. The Neem oil that I have used has always been mixed with water and soap and used as a dip in a bucket. Currently, I am trying other solutions so have no up-to-date data.

An orchid friend, recently mentioned that he uses different strengths of insecticide based on the different kinds of leaves - for thinner leaved plants he uses weaker solution. I do not know if this applies but maybe this could.
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Old 12-05-2007, 09:59 PM
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Quote:
Originally Posted by Cynthia, Prescott, AZ View Post
Sounds like you started with the pure Neem. All my problems have been with the hydrophobic extract.
Pure Neem? It has been about 3 years now, but it very possibly could have been pure Neem extract. It was very concentrated and thick like shampoo when it was cool in my orchid room, thin and watery when it was warm.
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Old 12-06-2007, 11:11 AM
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I am from Bombay, India. I use pure neem extract which is available at all our nurseries. I have not encountered any such problems. In fact all my orchids looks fresh after I spray them with neem oil. Only precaution is you should not spray during afternoon and it should be diluted with water and mixed with bathing soap.

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Old 12-07-2007, 01:31 AM
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The hydrophobic extract that is sold very commonly is specified as to be mixed with water only. I am sure that anything that specifies mixing with any amount of soap or detergent would be the pure neem oil.

All of my problems have occurred with great concern that both the heat and light were kept low after the initial notice of leaf mottling a few years ago. The GH was covered with additional shade cloth and the cooler thermostat turned down. The leaf mottling continued to occur in spite of keeping such conditions in effect for several days.
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Old 12-10-2007, 03:09 PM
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Upon reflection, it may well be that the neem I am using has suffered from excess heat. The total failure to kill any mites happened with neem purchased in the fall, and may have not had a chance yet to suffered from very cold temps, but may well have been affected by summer highs. I know that the Lowe's here in Prescott used the Phoenix model for their layout which put the neem oil products outside. Outside in Phoenix? Summer highs are 115 to 120 F. So, I wonder what temps are running in warehouses for the stuff that comes up here to hardware stores and nurseries, in addition to what comes to Home Depot and Lowe's. Most MSDS's state that storage should be between 55 and 95 F, and also most include 'SPECIAL SENSITIVITY: Keep from freezing'.

I have corrected the 'hydrophilic' to 'hydrophobic' in the above posts as that is the correct term for what I had been using.
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