The second dormant spray is best done as late as possible, diseases are more vulnerable as they are waking from dormancy. I spray at pink - when the blossoms have expanded but not bloomed yet. So, its not for several more months.

Scott

Thanks Scott. Boy the weather has been horrible!

I agree with Scott. Copper isn't good for the foliage when the tree is leafing out however you can spray it on up to bud break during the dormant season.

Can I do dormant oil and copper at the same time? Possibly even mix in the same container and do both in one spray?

city man, I always do dormant oil with copper in the same spray, its a standard method. Another good reason for my late spray is oil also works better when its put on as late as possible.

Scott

Thanks so much for that bit of info....you just cut two of my afternoons down to one! I'll wait until bud swell and knock out both sprays in one! Thanks.

I'm in zone 6 PA, I didn't do any spraying yet with all the cold and snow, Should I be putting on the dormant oil or the first coat of copper now for apple and peach trees? What about pruning?

I've also done copper and oil together as a dormant with no problem. I've always used oil when it's above freezing. It's supposed to be hard on tissues when used below freezing, so I've never done it.

If you are using copper to spray for leaf curl, you can spray now. You want the leaf curl spray on before buds swell, for optimum control.

I only do one winter spray for leaf curl, which has provided excellent control for me, but I understand some people have higher leaf curl pressure which necessitates more leaf curl sprays.

This post was edited by olpea on Wed, Feb 4, 15 at 20:48

Leaf curl has been just about the only malady/pest that hasn't hit my little orchard yet (knock on wood). But I'm willing to bet I have the worst fire blight many of you have ever seen. Two of my pear trees literally looked like they had been set on fire and there wasn't a single tip on my large pear that didn't die. Same thing with my big, older apple tree, and to a lesser extent some of my new small apple and pears. For this reason, I was planning on using copper this year to try and help with FB. Knowing that, when is the best time to apply copper for Fire Blight protection? Or is it even worth doing-I've read mixed reports on whether copper really does much good on FB. As usual, its all new and unknown to me so I'd love any comments. Can I still do dormant oil and copper at bud swell for FB? Thanks. (not trying to hijack ur thread, Mrs. G!)

That's cool cityman,all good questions and I have one.
I use Chlorothalonil for PLC and have never used Copper.For people using Copper and oil on Peach or Nectarines,what does the oil do?I only use dormant oil on Plums to help control Aphids,as they are the ones that get attacked. Thanks,Brady

Olpea, thats a good point about curl. I never have curl problems so I can put my copper on late. I am using it primarily for bacterial spot.

City man, copper for fireblight is also best put on latest. When I had bad fireblight I would spray copper at tight cluster stage. I have since switched to lime sulphur now that my fireblight problems have been minimized.

Brady, Dormant oil smothers any eggs on the trees. Peaches can get white peach scale for example.

Scott

Brady,

I used oil mainly as a sticker for the copper. Really I suspect bonafide labeled stickers work better, which is what I switched to a few years ago. To date, I haven't seen the need for dormant oil as insect control on peaches, which would necessitate its use on them, but I've not seen green peach aphids here so far either.

I too now use chlorthalonil exclusively for peach leaf curl with a good sticker, like Nufilm 17, which is what I used last year. I've now purchased some Tactic, which, according to posts on this forum, may provide more rainfastness than anything I have used thus far.

Saying that, I still see a film of chlorthalonil from trees I sprayed in Nov. using the Nufilm sticker, which also seems to work well.

Okay,thanks Scott.I hope there is never any of that Scale here.
I was thinking it might be used as a sticker olpea.The sticker I'm trying this time for PLC is from Southern AG.
The dormant oil is a Cornell U. recipe that calls for ultra thin Canola,but didn't know where to look for that,so just went with the stuff on the grocery shelf. Brady

Oil needs to be sprayed at above freezing temps only to protect growing green tissue- when trees are dormant temps don't matter as far as injury issues, but as Scott mentions, scale and mites are more vulnerable after trees first begin to grow. If you don't have a history of these pests in your trees, oil is likely not necessary- at least here in the northeast.

I've never observed any benefit to a spring oil application as far as aphids or leaf hoppers are concerned. They arrive in early summer regardless.

I have seen entire scaffold branches of huge apple trees killed by an oil application done while green tissue was frozen in hard frost. Tree care company was operating on a schedule of convenience to the operator.

There are copper formulations that can be sprayed on fully leafed out trees, which might come in handy if your problem is shoot fireblight and bacterial leaf spot.

Where I am, I've have never seen FB attack blossoms- it always makes its appearance in mid-summer on the new shoots and at a couple sites last year it was literally lethal on a pear tree or two. Apples were just lightly hit. Maybe copper included in my second insecticide spray (10-14 days after the petal fall spray) will help at sites with worst FB history.

The problem is that FB history never seems to mean much- it is an extremely erratic pathogen with no apparent rhyme or reason of where it will appear. In 25 years of managing orchards in SE NY I've never seen any consistency- one year one orchard gets hit and the next, another. At sites where it's been bad enough to kill a tree it has often only struck once.

Some seasons are worse than others, of course, but there is just no telling where the problems will occur. Other disease issues tend to always be better or worse at certain sites over the years.

Hman, in my spray program I use no bug poison and given that I think the oil helps with smothering any eggs of moths aphids etc laid on the tree bark. You are easily controlling a whole ton of stuff with general bug death sprays so I can see how the oil is not needed.

Brady, cooking oil doesn't go in solution ("oil and water don't mix"), you need a special formulation. I use soy oil for dormant spray, its thicker and dormant-only and provides more smothering. I use Golden pest spray oil.

Scott

"Oil needs to be sprayed at above freezing temps only to protect growing green tissue- when trees are dormant temps don't matter as far as injury issues"

Hman,

I've always read (without any qualifiers) that dormant oil should not be applied when freezing temps are approaching.

Below is what Cornell has to say about it (The webpage is from Penn State, but the article was written by Cornell's entomologist.)

"The primary cautions we advise when using oils at this time of year stem from their use, a) in association with or too close in time to applications of sulfur-containing fungicides, or b) just before or too soon after sub-freezing temperatures; both of these practices risk the occurrence of phytotoxicity, as oil's penetrant activity is capable of damaging the bark, wood, or bud tissues in these situations." (emphasis added)

This particular article discusses delayed dormant, but I would think the same risk would occur at dormant, since he mentions bark and wood tissues.

It doesn't sound like you've had any problems with a dormant oil spray in freezing weather. I've just been afraid to try it because of the warnings.

I use dormant oil on pears for control of blister mite and sometimes during the growing season for mites on apples.

Here is a link that might be useful: Penn State Delayed-Dormant Oil Sprays

I believe that the tissue is only vulnerable to oil when trees are in growth. Previously to the development of these highly refined oil trees were always sprayed while completely dormant and I don't recall any concerns about spraying when it was too cold. When trees are dormant most nights are going to have frost and unrefined oil stays on the tissue for much longer.

Well, I'm still not convinced. There seems to be warnings all over the internet about using oil as a dormant spray when frigid weather is imminent.

From the link below:

"During the dormant period, spray Horticultural oil when the temperature is above 40degrees F and when freezing will not occur before the spray can dry."

I'm sure over the years, you've sprayed dormant oil in freezing weather, and from your posts, haven't experienced any problems. Additionally, I'm not saying the warnings aren't overly cautious (as an example I've sprayed captan when conditions suggest high phytotoxicity without any problems) but there do seem to be warnings for dormant oil sprays and freezing weather, which is why I haven't tried it.

As an aside, perhaps I'm misunderstanding your explanation. Are you saying old dormant oils were more risky in terms of tissue damage during dormancy, whereas new highly refined oils are less risky in this regard? I would agree w/ that BTW.

If so, I respect your experience, but still I haven't read anything in the literature which suggests even new oils are completely safe to apply close to freezing temps. I also worry about it because I can definitely see a very distinct discoloration in the bark after a dormant oil spray (which confirms to me even new oils have deep penetrative ability in the bark).

Again I don't doubt your experience with this, but just offer an explanation why I've been cautious to apply dormant oil near freezing weather.

Here is a link that might be useful: U. of Tenn Ext. - Horticultural oil handbook

This post was edited by olpea on Fri, Feb 6, 15 at 20:52

No comment on the Cu but as far as Cu + oil on peaches, I recall reading that oil apps can have a tendency to induce peach trees to come out of dormancy bud out and maybe lose the blooms to Spring frost. Anybody see that one before? I too have been doing great with a leaf fall app of chlorthalonil on the peaches for PLC and Shothole. If I can squeeze in a Spring app I do but more often than not can't.

Thanks Scott,that's very good to know.I suppose food grade Soybean oil of some sort can be used. Brady

" I recall reading that oil apps can have a tendency to induce peach trees to come out of dormancy bud out and maybe lose the blooms to Spring frost."

Yes Michael. I've read the same thing (oil inducing early bud break) as well as early pruning encouraging the same.

For our area, as far as I know, the commercial growers I know apply only one chlorothalonil spray in the fall for PLC. This has been my practice for quite a few years on my backyard ochard, as well as my farm orchard (I've never applied more than one PLC spray on the farm orchard) and had excellent results thus far using chlorothalonil.

I made my first spray of the year today. Sprayed my peaches and plums with Bonide Dormant oil. Since my peaches are at bud swell (some pink), I will spray copper next week.

Question: I had some fireblight issues last year. I was going to try Fertilome Fireblight Spray. No one here has mentioned it - does it work? Supposed to spray it at full bloom. Anyone have any experience with this stuff?

Outdoor334,
I haven't used it,but remembered reading a post about a guy getting good results.
Here's a link. Brady

Here is a link that might be useful: Disease on Asian pear trees

Olpea, I suspect the literature is either based on the fact or mistakenly based on the echos of the fact that all commercial applications of oil are now done as delayed dormant sprays when trees are in growth. I too could be wrong, but the old labels of true dormant oil did not carry warnings about spraying around freezing temps that I recall.

I just found this, which may explain the literature you've come by. According to this guideline, if you spray the new oils when it is freezing they don't work properly. Maybe this wasn't a problem with heavier oils. I don't quite trust this guideline though, because it doesn't mention the danger of spraying green tissue near freezing temps.

Here is a link that might be useful: hort oil