A couple of my trees (Empress, Golden Transparent Gage) started to develop this:
Several of my trees last year had heavy infection from this fungus (?). I think I need to spray a fungicide soon.
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Dang!
That top left leaf looks like bacterial shot hole but the remainder do not.
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nope
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Me neither. Looks a bit like shot hole and a bit like leaf burn from a spray. But may not be either.
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Strange its only on one ot two leaves. The others look nice and green and healthy.
It can be caused by two distinct pathovars of Pseudomonas syringae: pv. morsprunorum and pv. syringae
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That’s not strange in my experience; when disease inflict a tree, specially in earlier stages, only a portion of the leaves show symptoms, eventually if not sprayed or if the tree is highly susceptible, all leaves will show symptoms and the whole tree can get defoliated.
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Are you sure this is inevitable. I’ve seen viral diseases like apple mosaic that only affected a few leaves on certain seasons but never spread to the point of being important- which is lucky because there is no treatment.
I have also seen a wide range of severity of certain fungal disease like CAR.
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If it were my tree, regardless of ID, and since nearly all fungus produce spores, I would treat it to kill any spores that are likely to be deposited in the tree bark. Probably once now after leaf fall, and again before bud break. Then monitor the results next spring to observe effects. It’s most likely a fungus perhaps caused by existing evergreen trees nearby. So look around for that type of growth. Could be you simply need to keep experimenting for the best treatment. Does it affect other fruit trees that you have. I have had shothole that was self inflicted by my poor watering practice. Once I made that determination, and corrected, the shothole has not returned. Now I am experimenting on preventive solutions for two other symptoms of PLC and Aphids on my plums. Trying a different treatment each time this week, then a different one next week, then one before bud break. I will keep notes on each application, and in next season determine if it was helpful.
Good luck,
Hope you find a treatment that works
Dennis
Kent, wa
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@alan my experience is much less than yours, but here are my observations:
1-In 2022 I observed the same lesions on some of my Euro plum trees in August, I didn’t spray, and by mid September those trees were almost completely defoliated, I also noticed wide spread death/drying of the fruiting spurs on these trees (which I guess happened as the trees were stressed, so sacrificed fruit bud formation for the sake of keeping the tree alive through the winter). In 2023, my Euro plums showed the same symptoms, but this time I dprayed with fungicide immediately after I observed them. The result was a little bit of defoliation, but the trees kept there leaves through October, and also much less spur death.
2-With Cedar Apple Rust and Marsonina leaf blotch, sensitive varieties get almost completely defoliated if not sprayed.
3-With Bacterial Spot, I saw massive defoliation on susceptible nectarines when not sprayed.
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I try to minimize spraying, and before growing apples and Euro plums my last spray (for stone fruits) used to be around mid July. Now I have to spray apples in August for Marsonina Leaf Blotch and bitter rot, so will spray Euro plums with them.
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I’m sorry, I only looked at your comment that I was responding to and had long since forgotten that it was your topic and that you’d submitted photos. That comment standing alone seemed like a suggestion from someone answering someone else’s question.
Of course your experience is more significant than my comment, which was a general observation and not specific to the symptoms of issues your trees have been suffering. In your position I would submit samples to a tree fruit pathologist through your cooperative extension to your land grant university. If you haven’t done this yet it might help you work out a more precise treatment. Cornell charges about $35 for this service so it would probably be well worth it for you. I am curious what might be found, but it will have to wait another season and you will have to leave at least a part of one of your trees untreated with your current fungicide strategy. .
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The second photo looks like the way Leaf Scorch progresses,from the edges.
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Good idea, I have done it a few years ago (it was with University of Delaware extension, and was a free service back then), but didn’t occur to me this time. I’ll probably do it if I see this disease again.
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