Can anyone help ID the disease and suggest possible treatment.?
Fruit already forming on both plum and pear …
AMBROSIA PEAR
![pear 2|480x640]
GREEN GAGE PLUM
(upload://cMZYHrV0EhWP2ELt0IzuxThNHQc.jpeg) 
On Plum is definitely Black Knot.
The pear pic was not in focus. It is hard to tell.
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Def looks like black knot on the plum…
What are you doing about it besides pruning?
No way I can remove all affected branches. It’s in many places.
How about sprays?
Not too concerned about the pear yet. Here’s another still not in focus just in showing different spot.
If referring to the gray growths on the pear, those are just lichens. Nothing to worry about.
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What variety is your plum? If your plum is a black knot magnet, you are fighting an uphill battle. Once black knot shows up, you need to remove either the knot or the branches it is on. There are people who removed black knot magnet trees to solve the issue.
Spraying Captan in the spring is suggested. By now, it may be too late to spray.
Here’s what Cornell said.
http://chemung.cce.cornell.edu/resources/black-knot-disease-of-cherry-and-plum.
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Yeah. The gray stuff. I’m not religious but bless you for the news.
This plum in question tree is a Green Gage.
I’ve already lost a Stanley and I’m about to lose the Japanese plums - a Santa Rosa, a Shiro, and an Elephant Heart (although after many years I’ve never gotten one E.H. plum from the tree).
The Shiro has been reliable but I’ve had to cut the tree back by a half. What’s left fruited again this year.
Anyway, there so many affected spots on the G.G. I’m afraid it’ll be a goner.
One question- if you know, will the mature fruit be edible?
Yes, fruit are edible. BK does not seem to affect fruit, only the trees.
I think @thecityman has been able to get black knot under control with his spray combo. I think it’s Captan and Immunox or something like that. Hope he will chime in.
The gray on your pear looks like lichen. Won’t hurt your tree.
Thanks very much. Great to hear.
That would be great. I already have both Immunox and Captan on the shelf so I can give them a shot.
I’m curious to see how bad the situation is when the leaves have dropped.
I’d rather not have to take the tree down.
On the Black Knot thread, @alan stated that Cornell recommend chlorothalonil. A common brand is Daconil but it cannot be spray after fruit form.
Read up on black knot. It is spreading more if you don’t have good control. It is not an easy disease to control.
I’ve heard of Daconil. I’ll try it. Thanks again.
Sorry, but I have not been able to control black knot. You may be thinking of Brown Rot or Black Rot (on grapes), both of which I have had great success controlling. But I have had absolutely no luck at all controlling black knot on some trees. In fact, I have 2 trees who look exactly like what @mrsg47 recently described as having “dog poo” hanging from all the branches. Even when I actively cut away every beginning sign of BK, I can’t keep up with it. From my experience, either its a plum/pluot that isn’t susceptible to black knot, or else its a tree that is and there isnt much you can do to stop it. Certainly cutting it out keeps it somewhat under control and therefore is recommended, but in my experience it is always going to come back on thoses trees that have it.
As ugly as it is, I will also say that even my
“dog poo” trees still manage to leaf out and produce fruit for years. Eventually I’d say it will be a death sentence but I’ve had a few get so bad that I couldn’t possibly cut it all out and they still produce for the last couple years- though eventually I’d say they cannot continue to live with that level of infection.
Long store short, about all I can tell you is try to get trees that aren’t susceptible. In my orchard I’d say only about 10% of my plums and pluots get black knot. Each one of them- even the worse infected ones- are a few feet away from other plums that never get it. Good luck to @bubbabgone but I can’t offer you much hope beyond you having to constantly cut out infected wood as long as you have the tree, and if you aren’t vigilant it will get to a point where you’ll have to cut most of the tree away or give up and let nature take it course. But you may be surprised how long the tree will still produce. As for it infecting your other trees- my experience is you can’t stop that on some trees and can’t cause it on others (most).
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Thanks (sort of) for the realistic appraisal and the poo laugh.
I kind of figured the doomsday scenario would likely play out…
I’m considering letting it go for a while to see how long it’ll go despite its “so bad that I couldn’t possibly cut it all out” condition.
It’s somewhat close to a White Gold cherry tree that I think is resistant to Black Knot … at least so far.
The Gold Cherry is a little farther away and seems to be okay so far,.
I’ll have to decide what to do this Fall.
I’d say others will tell you to hurry up and get it out, and perhaps that is smarter. But again, my experience is that trees that are going to get BK are going to get it, and those that aren’t are not. I’ve got two that are worse than yours but they are both surrounded by dozens of other stone fruits and very few have gotten it. And as I mentioned, my tree has been covered in it for years and still been chugging along pretty good except for the ugly appearance.
Here is a couple photos of one of mine, so you can see where yours is headed!!! ha
Lucky for me I have never seen black knot that bad.
Keep in mind that photo was early spring before the tree leafed out. It doesn’t look nearly as shocking or noticeable when the tree is leafed out.
Sorry to confuse your success against brown rot with black knot.
At one time, 1990, Cornell recommended Captan for Black Knot but in 2000 changed its recommendation to chlorothalonil.
I think the fact that you have been spraying some fungicides i.e. Captan and myclobutanil, it helps offer some protection to your other trees even if those fungicide are not that effective against Black knot.
For people who don’t spray like you do, keeping trees full of black knot may not be a wise idea. All I can tell you if that you were my neighbor and keep black knot-ladened trees like that next to my orchard, I’d not be happy, cityman or not 
haha. You make a very good point and I should clarify…in no way do I think its a good idea to let black knot just run wild around other trees. And you may be right- my use of 2 fungicides on all my trees on a regular basis may well be why BK hasn’t spread more than it has. I’m no expert or scientist (though we have some of both here) so all I can do is report what I’ve seen. And in my orchard I’ve seen about 5 trees get BK, and no matter how aggressive I am in cutting it way they just get more and more. Meanwhile, the vast majority of my trees- and they are all pretty close- never get it. So over time what I’ve experienced is that some trees get and it keep getting it no matter how hard I fight it, while most of my trees do not, even though they are exposed.
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