I can't answer about fungicides but I can answer about fall pruning.

"As with all stone fruits, prune as buds burst when training a young apricot, and in summer when the tree is established. Never prune in early winter when the risk of infection by disease (see Plum problems p.123) is at its greatest." per American Horticultural Society- Pruning and Training.

I was going through the pruning section on fruit trees. I saw that I missed the window on my Apricot too. Next spring/summer I'll get it. Hope you do too.

By the way, they bloom on 2 or 3 year old wood. So when you prune to open the center of the tree, Leave some branches of that age so you will get some fruit. Look at a branch from the end, then look lower on that branch until you see where it started to grow from the previous year. It will look like a collar or wrinkled spot on the branch. Then go down one more year.This should be your fruiting area. Sorry if this is old information for you.

You probably want to split the pruning into at least 2 years. It wont look perfect for you but it will be easier on the tree. This is why the rule of thumb is no more than 25% removed per year. This should also help with your fungal problem.

I did not know that pruning it in winter increases the risk of disease infection. Thanks for the info.

I just did some research, and found out that it is also fine to prune it in fall:
http://aliveeastbay.com/archives/the-dirt-gardener-pruning-apricot-trees/
"September and October are excellent months to prune as the trees are in the beginning stages of dormancy"

At this point, I just want to get rid of the disease, so if I don't get any fruits next summer, it doesn't matter. We are used to not getting healthy looking apricot fruits (they're always covered with brown spots).

Honestly, I would like to cut 50% of the tree, so that I can apply a fungicide. Pruning is going to be a hassle, too!

What are your thoughts?

Prune now and put down your chlorothalonil when leaves fall and again at bud swell in spring. If you see shot hole in early spring put it on again; don't spray it when it starts to get hot though - it can only be used in early spring. I don't use that chemical but make sure to check the dose rates, usually dormant doses can be stronger than growing season ones.

Scott

I will prune the tree this weekend. I have a question. Is it a problem if I prune the tree and then a few days later, it starts to rain? So far between Saturday and Tuesday night, it might rain a bit (2-4 mm) on Monday, but I will confirm this with my friend who is a meteorologist.

The reason why I ask this is because on this site (http://www.visaliatimesdelta.com/story/life/home-garden/2014/07/17/time-prune-apricot-cherry-trees/12770557/), it is stated:

"Summer pruning should be done anytime from mid-spring with no rain on the horizon through summer and no later than Sept. 15. This will provide at least six weeks for the wounds to heal and a long period of rain-free weather, which will reduce susceptibility to the disease.

I don't live in the desert, so it will always occasionally rain. But does a wound really take six weeks to heal?

Is this something I should be concerned about?

Never prune in early winter when the risk of infection by disease (see Plum problems p.123) is at its greatest." per American Horticultural Society- Pruning and Training.

jbraun...does it specifically say when it is that you're to prune? Does it mention why disease pressure is greatest in early winter? Are they comparing this to late winter...or summer/spring or what?
I was under the understanding that late winter was always the best time to prune (save for summer pruning to head growth) and I thought the primary reason was that infection likelihood was at it's lowest, combined by the fact that the tree is fully dormant with it's energy stored fully in the roots. The tree is fully dormant and insect and fungal issues are almost non-existent. What is it that I don't know here?
What book did you read that in and what chapter/page...I'd like to learn more.

Appleseed70,

The American Horticultural Society PRUNING & TRAINING by Christopher Brickell, David Joyce. Apricot info on p. 136.

I quoted the whole paragraph on Timing of pruning. It recommends bud burst for training new plants and summer for established plants.

They don't mention the why or the comparisons.

Your second paragraph goes into more info than the book does. So you know more than the book states. This book covers tons of plants and different pruning methods used. So they only give the basics here.

This book seems to be a collaboration between the staff of the Royal Horticultural Society, England and the American Horticultural Society Alexandria, Va. At least they got a special thanks on the title page.

Six weeks is not how long you need to try to avoid rain. Studies show 3 days of no rain after pruning and your odds of infection from the rain are zero. If the tree is isolated from any other apricot/cherry/plum trees your susceptibility to canker is much lower and you probably could prune any time including in the middle of a rain.

Scott

Thanks, scottfsmith.

Appleseed70, I read that apricot trees are one of the exceptions. According to the articles I read, it is recommended not to prune in winter due to an air-borne disease called Eutypa:

"Pruning apricot trees during the winter months can be problematical during wet damp periods. Apricots are susceptible to an air-borne disease called Eutypa that enters through the fresh pruning wound(s). The disease causes a sudden die back of the limbs and branches in the canopy during late spring or summer. Unfortunately, this disease has no chemical treatments [...] You avoid the problem altogether by pruning in the late summer or fall. ."

In CA it's recommended to prune apricot in late summer because that's the driest time of year there. Obviously that's not the driest time of year in much of the rest of the country. Plus CA is the only place where I've heard of Eutypa die back being a problem. It could be elsewhere.

If people would list their location it would be easier giving advice.

fruitnut,

I live just outside of Montreal, so north east. The more I research about this, the more confusing it gets. Different articles recommend different pruning season for apricot. But I'd like to do it now.

Appleseed70, I read that apricot trees are one of the exceptions. According to the articles I read, it is recommended not to prune in winter due to an air-borne disease called Eutypa:

Thanks Ghadames...I never knew that, in fact I don't think I'd ever heard of that disease. So there are diseases that are not only not deterred by cold, but in fact, thrive in it.

I've never heard of Eutypa in Eastern USA or Canada. There's a good chance it's not an issue there. Plus CA is a whole other world from Montreal climate wise. Infection can occur in winter in CA because that is the rainy season and it's warm enough for spores to germinate.

Even if Eutypa is present out east and I doubt that, winter isn't the time that infection would occur there. I'd wait and prune in late winter.

I read that Eutypa is mostly present in North California and the San Francisco area, so fruitnut may be right. The Canadian articles I read state that apricots should be pruned in early spring like other fruit trees.

My only concern is that if I don't prune it now, then the disease will overwinter in the buds. I wanted to prune it now so that it would be easier to apply the fungicide. I'm not going to apply it without pruning it. The tree is too high, and it would be too much of a hassle. Can I still get the same level of protection/prevention if I apply the fungicide when the buds open up in spring?

Also, after pruning the tree in spring, would it be a good idea to apply copper spray before the buds open up for extra prevention?

This post was edited by Ghadames on Sat, Oct 11, 14 at 14:07

Plus CA is a whole other world from Montreal climate wise. Infection can occur in winter in CA because that is the rainy season and it's warm enough for spores to germinate.

fruitnut makes an excellent point here ghadames and possibly the reason for all the conflicting recommendations. No doubt a lot of this info is in regards to California since such a large amount of stone fruit is commercially grown there.
I'm with fruitnut on this, I too would prune late winter. If for no other reason than it makes sense to me and seems to more closely follow conventional wisdom. Not saying that is right, but that's what I'd do.

I will prune it in early spring, but I have a few questions.

Is it fine if I prune 5-10% of the tree? I would like to keep a few small branches in a V shape. Can this harm the tree? I want to remove all the top branches. No point in keeping them, can't even reach that high. I've read that pruning a lot during summer can potentially kill an apricot tree (bleeding it to death), but I'm assuming it would be safe to do it while it's dormant?

I've marked the branches that I plan to keep. I will apply a copper spray fungicide on them next week. A week later, I will apply a chlorothalonil fungicide just for some extra protection. In early spring, I will remove the rest of the branches, apply copper spray fungicide. When the leaves open up, chlorothalonil will be applied.

Assuming that there would be a lot of new growth in summer, the following spring, I will prune out all the old branches and only keep the new ones. All this just to make sure that the disease is hopefully completely gone.

Does this sound like a good plan?

This post was edited by Ghadames on Wed, Oct 22, 14 at 22:35