There are numerous discussions about this topic here. It depends upon your definition of "organic" is how most of the threads go IMO.

That is: I'm not sure how a bordeaux mixture isn't "organic" but I'm sure someone will come along and state compounds in fertilizer can be determined by plant roots as being organic or not too...

Organic orchards are the toughest job in organic, if'n you ask me. Lots of losses in many years. And if you see what the "organic" orchards spray in the Columbia Valley, well...

Dan

Not a dormant spray situation, but perhaps more important sometimes is a fungicide spray at blossoming time. There are what are considered organic ones with Spinosad in them

ashley: what do you want the spray to do, smother overwintering insects? Are you aware of any existing/past problems that a dormant spray would be useful to control?

If one is using the term 'organic' to mean 'certified organic' by the agencies that do so, Bordeax mixture has always qualified and always will. FYI.

Dormant oil is a term to define a horticultural oil applied in the dormant season. Any horticultural oil can qualify as a dormant season oil. Thus, if you do a search on 'organic horticultural oils' you'll come up with plenty of vegetable based products.

If you are NOT expressly interested in qualifying as a Certified Organic orchard, and want to use environmentally friendly product, I believe that almost any you could find would be fine.

There are many dormant sprays acceptable to organic growers and which to use depends on what needs to be controlled. Bordeaux Mix is acceptable, providing due care is used in use and application. The ingrediants are known to have detrimental affects to both aquatic life and earthworms (therefore the Soil Food Web) so timing of applications is critical. For many years the only dormant oils available were derived from petroleum products, a non renewable resource, but there has been research that shows that many of the vegetable oils will do much the same thing.

Here is a link that might be useful: About Dormant Oils

Thank you all. My purpose is to kill any insects in the fruit trees. My cherry tree had leaf curls and my apple tree had brown leaf spots last year. I will also go to my local nursery and ask for their recommendations.
I would like to avoid petrochemical derivatives, if possible. I am originally from India where Neem oil is extensively used in orchards and in agriculture. I am wondering if Neem based products are a good option for me.

Leaf curl and necrosis likely aren't insect-caused.

You will want to re-think your approach until you get a basic understanding of the issues with your trees.

Dan

Dormant sprays will only target overwintering insects or their eggs. If the pests occur later in the season - after the trees leaf out - a dormant spray will be of no use. And I agree with Dan that leaf curl and most leaf spotting are typically not insect caused problems but rather the manifestation of a fungal or bacterial organism. Dormant sprays could help in that regard but the problem still needs to be correctly identified before any effective control can be initiated.

IOW, you don't spray anything until you know exactly what the problem is.

And further, I wouldn't go to a nursery for help, as they will sell you a product they carry, which may or may not be what you need.

Rather, call the extension agency for your county to get a handle on what it is you have and want to do - that is: learn what you need to do before you do something. This will save you time and money and will avoid wasting resources on ineffective actions.

Dan

Found this in the A.M. Leonard catalog today - PureSpray GREEN Horticultural Spray Oil. It is indicated for a growing season spray, not dormant season and is listed by ORMI.

Michael

And further, I wouldn't go to a nursery for help, as they will sell you a product they carry, which may or may not be what you need.

LOL! Dan, I could be persuaded to take offense at that statement :-) At my nursery, we have a number of CPH's on staff (Certified Professional Horticulturists) with considerably more training and experience than do the extension office workers, who are by and large almost entirely Master Gardeners with very limited training. Plant diagnosis and treatment recommendations tend to be a lot more accurate coming from the nursery than they do from the extension office. I do realize this is not the case everywhere, however. As a result, I tend to be much more successful selling plants than I do products, as I seem to discourage more purchases than not as being unnecessary :-)

Michael, the OP expressed a wish to focus on plant/vegetable based oils rather than petrochemical ones, so the referenced product is not likely what he/she is looking for. And while it may help to control some insect issues, it would do nothing for the cherry leaf curl (which is fungal based, not treatable and should be removed by mechanical means - pruned out) and may or may not have any effect on the leaf spotting depending on the source, which could be one of any number of problems, insect or disease. IIRC, all horticultural oils regardless of derivation are considered approved organic controls.

Again, you don't spray anything until you know exactly what the problem is. And then only with a product that is registered to control that specific problem.

I knew I could yank your chain, GG. I can guess where you work and I'll assert most aren't like your nursery - I had a landscape design and construction business in Sacto, and let me tell you there were very, very few nurseries I'd send my clients to and two where I had an account. And here, our Ext Office is much better at diagnosis than in WA (altho taking it to CUH at UW would be good, IME).

Dan

G-gal:

"the OP expressed a wish to focus on plant/vegetable based oils rather than petrochemical ones"

Yes, I am aware of that but ashley was also looking for an organic product as expressed in her original post. Knowing that isn't always possible to find exactly what we want, I offered up the link that she could follow. I too believe an oil would not be useful for the curls and what could have been scab on the apple, but chose not to comment on those issues; instead, assuming the point not to spray until one know's what one is dealing with had been understood.

Michael

Ashley, it sounds like the problems are fungal. If you do spray oil, it should be one that controls rots/curls applied when the tree is leaf-free (no point spraying if not defoliated). Good cleanup of all leaves might do more than spraying even, as you want to eliminate any overwintering pathogens.

I guess I don't understand the logic in not spraying until the problem is identified. In general I understand the idea, and agree with it as treating the wrong problem can lead to other problems.

In the case of a dormant oil spray applied during the dormant season I see zero possibility of any harm.

Heck, I dormant oil spray all my fruiting trees every year no matter what. An ounce of prevention... I started doing this due to Asian pear trees having foliage problems that defoliated the trees 2 years in a row. Nobody could ID the problem and to this day I don't know the specific problem. The leaf buds would open already affected. Spraying during the dormant season resolved whatever the problem was and I am sorry I lost a season of good growth trying to definitively ID the problem.

And no, I don't know of any plant based dormant oil I could recommend. While any oil can do the job, I prefer those with instructions for mixing rate for the dormant season.

Dormant oil sprays are meant for controlling insects and they work by preventing the some insects from breathing which will cause death. However they do not work on some insects. Research has found that vegetable oils work as well as the petroleum based oils, although there are indications (probably because of late application) that there is more phytotoxicity with the vegetable based oils. Reseach has alos shown that Neem Oils are just as effective as petroleum based oils.

Here is a link that might be useful: About Dormant Oils

I guess I don't understand the logic in not spraying until the problem is identified.

The logic is you may be wasting money treating the wrong problem.

The argumentation in this thread is to help understand the diseases of orchard trees, the cultural requirements to eliminate the pathogen, and the appropriate treatment including timing of application. There is no evidence in the OP that this context is understood, thus the discussion's direction and content.

Dan

I'll expand Dan's comments further by stating that the first rule of pesticide application is that you only treat once the problem has been identified. This applies to both organic and non-organic controls. One can liken the situation to a person suffering from chest pains - do you assume it's a heart attack and start CPR or electric shock when in fact it may only be indigestion? Or vice versa? Correct diagnosis is the key. While dormant horticultural oils have a pretty low environmental impact, they ARE non-selective and will kill beneficials as well as problem species. And the aforementioned concerns regarding phytotoxicity, which can occur with either product depending on plant species.

And why would one bother with the time, effort and expense of applying a dormant spray when it will do nothing to curb the underlying problem? If it is overwintering insects, that's one thing, but if it is a fungal or bacterial pathogen, you are just messing about unnecessarily.

And why would one bother with the time, effort and expense of applying a dormant spray when it will do nothing to curb the underlying problem?

I think we will just have to agree to disagree here. I regard a dormant oil application to be so non problematic that it's worth doing preventatively in cases where a tree type is known to have lots of problems with local pest/diseases. To the extent that last year's problem is treated it reduces/eliminates the need to experiment with more toxic controls during the growing season. If the dormant oil doesn't solve the problem, there isn't much, if any, harm done to the tree, beneficial life, or the overall environment.

I do agree with trying to ID the specific problem, no doubt about that, but I still consider it of value to use dormant oil sprays on trees known to be very susceptible to a wide variety of pests/diseases.

JaG, unless dormant oils are combined with other products - sulphur or copper/lime solutions are common - they DO NOT address disease issues. And not all disease pathogens are effectively addressed with a dormant season spray anyway. The cherry leaf curl is a case in point - it is not treatable with home-based remedies and the affected portions must be pruned out.

Yes, we can agree to disagree but please understand the reasoning behind the statements made.

Here is a link that might be useful: How/why to use horticultural oils

JaG, unless dormant oils are combined with other products - sulphur or copper/lime solutions are common - they DO NOT address disease issues.

The link you provided contradicts what you are saying ;) It plainly says horticultural oils have been found effective against some fungal pathogens.

It also didn't address dormant oils, just horticultural oils (unless my skim reading missed it). Applying a dormant oil is different than using a lighter weight oil during the growing season. The purpose of a dormant oil is that it is heavier and denies oxygen entry through itself. Anything overwintering on/in the tree that requires oxygen will likely die. Such an application can't be made during the growing season without major damage to the tree because the tree needs oxygen during the growing season, but can survive for awhile without it when fully dormant. The article did address the use of horticultural oils on dormant trees very briefly in that it mentioned it can delay bud break/blooming. This would be very desirable in areas where the springs can go from warm to sub freezing overnight. It's not relevant to the OP, but it does point to the value of using dormant oil sprays as part of a routine program rather than waiting to ID a specific pathogen.

Every source I have ever read finds dormant oils applied during the dormant stage to be effective against many insects, their eggs, larvae as well as many fungal pathogens overwintering even as spores in the bark/buds.

I don't really see a down side to routine applications during the dormant season. The link you provided didn't address any.

Horticultural oils, as described in the LC-S arty, are not appropriate for the likely pathogens the OP has. Rather, the OP needs some sort of cupric sulfide- or copper sulfate-type application.

Just as willy-nilly spraying of stuff all over the place "just in case" can try to be justified to support past poor practices, so can avoiding spraying be justified against the "just in case" fallacy, in order to prevent death of beneficials. Basic, basic, basic cultural practice (and economic practice) is you don't treat until you see a symptom. Basic.

Dan

Basic, basic, basic cultural practice (and economic practice) is you don't treat until you see a symptom. Basic.

Agreed. So what would you suggest when you do see symptoms and you can't ID the problem nor can the local extension office nor the excellent family owned nursery that sells the stock?

Why wait for an unidentified problem to reoccur when a relatively non toxic solution exists that may or may not work against the problem pest/disease? What is the harm in trying?
After trying various solutions of varying toxicity that don't work a relatively non toxic dormant oil is applied and the problem goes away.

What's the problem? Citing a mantra of 'don't treat without a positive ID' doesn't make it true or effective. What real world harm results from a dormant oil application over the winter? What's the drawback other than potentially wasting an ounce or two of oil?

Citing a mantra of 'don't treat without a positive ID' doesn't make it true or effective.

False premises distracting from the process notwithstanding, repeating true statements doesn't make them true, obviously. The evidence behind a statement makes it true.

What's the drawback other than potentially wasting an ounce or two of oil?

Aside from wasting time, energy and resources, I repeat my statement @ Sun, Jan 10, 10 at 17:42: avoiding spraying [is] justified ... in order to prevent death of beneficials. [emphasis added]

Dan

Thanks for all your effort in helping me out. Sorry, I was not intending to start any debates. Just expressing my wish to stay as organic as possible in my fledgling home orchard.
I did ask a Certified Professional Horticulturist at a highly regarded nursery in my area which also a promotes organic gardening practices about my trees and their affliction. Since my trees have defoliated now and there is no way I could show them a sample of the damage, they suggested that the damage could be either due to bacterial or fungal infection or aphids (also known to cause leaf curls) or mites. Pretty much the sum of all your posts here :) So, now I have suggestions for dormant oil sprays, sulfur and copper.
I am waiting to talk to a county extension agent tomorrow to see if they can diagnose my problem trees before taking any action.
Due to some health issues, I had hardly stepped near those trees last year. So, I am not even sure if the trees were crawling with any insects or if the damage was more bacterial or fungal. This year, since my health is better, I am putting in 5-6 more new bare root fruit trees from Dave Wilson Nursery and I do not want whatever it is afflicting my existing trees to pass to my new trees. Your advise is very much appreciated.

Just a word of caution, sulfur and oils do not mix, they will injure the tree. You can use an oil in the dormant season and then use a sulfur product in the growing season if necessary, but once you use sulfur, don't use any oil products for a good month or so.

Ashley, debates here on the Organic Gardening forum are pretty much par for the course :-) In most cases, they are healthy and good-natured exchanges of information and practices and benefit us all by providing different viewpoints. Of course, it is upto the OP to research the differing camps to determine which approach will work best for them. Or if either have any merit, for that matter!

JaG, lime-sulfur is often mixed with a dormant oil and there are products on the market that offer prepackaged combined solutions, Bonide is one. The combination won't injure the tree if it is deciduous and fully dormant - the problems with phytotoxicity occur if combined for application after the plant emerges from dormancy and begins to bud and leaf out. Then one must use a all-season horticultural oil and wait an appropriate period before applying the fungicide - typically 2 weeks is recommended. And sulfur sprays alone can be phytotoxic to a lot of plants - conifers and most broadleaf evergreens at any time, Japanese maples when in leaf and only within certain temperature conditions for other plants.

If one is doing 'preventative' spraying (which I don't necessarily advocate for all the reasons stated previously), a dormant spray combo like this is the way to go - the oil to smother any overwintering insects or their eggs and the lime-sulfur to address any overwintering fungal pathogens.

FWIW, these are all considered organic controls.

Here is a link that might be useful: Bonide Oil and Lime-Sulfur spray

Thanks justaguy and gardengal. The county extension diagnosed my tree's problem as "Black Cherry Aphid".

JaG, lime-sulfur is often mixed with a dormant oil and there are products on the market that offer prepackaged combined solutions, Bonide is one. The combination won't injure the tree if it is deciduous and fully dormant

LOL, I know. I feel like we have been talking past each other a bit. I think part of the problem is distinguishing between trees that are dormant and those that are not.

During the growing season oils and sulfur should not be mixed. During the dormant season it's anything goes.

Aside from wasting time, energy and resources, I repeat my statement @ Sun, Jan 10, 10 at 17:42:

avoiding spraying [is] justified ... in order to prevent death of beneficials. [emphasis added]

From the beginning I have limited my responses to those applicable to the dormant season when deciduous trees have no leaves and their buds haven't yet begin to swell.

Within that context, what beneficial would harmed by an oil spray? For context, I live in Wisconsin and my trees are covered to the 1-2' mark with snow. I don't see too many bees around these days and I don't know of any insects that would lay eggs on my trees unless their young would feed upon them, thus removing them from the category of 'beneficial'.

Perhaps I wasn't clear enough, but what I am recommending is a dormant oil spray DURING THE DORMANT SEASON to potentially control overwintering insects and fungal pathogens so they aren't present the following year. I recommend this be done as a matter of routine on deciduous plants know to experience a high level of pest/disease problems for genetic reasons and see zero harm to beneficials, the tree, the environment resulting.

Where am I going wrong?