Two years ago I had to cut down and burn a wonderful Starkling Delicious red fleshed plum due to a black knot infestation. I had been hoping it wouldnt spread to my Bruce Plum, which it has done, or God forbid to my incredible prolific Redheart Plum. Well, I went up the orchard ladder this afternoon to pick some Redhearts, and low and behold the entire canopy was infested with the emperor of all plum cancers.
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That’s terrible, Patrick. I’m sorry to see it. That stuff is tough and just all over around here- and I don’t have any good suggestions. Others may. Good luck to you.
Ooh that is ugly. Only had to cut one small branch a week ago. Hate it!!
Sorry, Patrick. Black Knot is really awful.
About all you can do is cut it out. Odds are with that much BK you will continue to have reinfections until you loose the tree.Its probably best to cut the tree down. If you want to try your hand at grafting, a new tree will come up from the roots and grow fast… You can graft onto it and have a fruiting tree in two years. I did this with a Methley. Find a variety that is BK resistant and only grow resistant trees for a couple years until the spores are gone. It’s a bummer. I had to start over with my plums. It also seems like the best plums are prone to BK.
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American plums are extremely resistant to black knot. I grow them right nearby wild chokecherry that is infested with black knot and never see it on the American plums. I think growing Americans and Japanese x American crosses is the best way of dealing with black knot.
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Well that explains that. I was reading this thread and thinking, that’s odd, I’ve never seen BK on any of my three plums, yet it horribly infests Amur chokecherries and mayday trees in my neighborhood. But two of my trees are American plum, and the other in a Japanese-Canadian cross (Pembina).
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It looks bad. I hope someone can pass on some advice to help.
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I’ve got a tree down the road from me that looks like that (and has for a year+). It is jn the property of an apartment building. As of this past spring I’m cutting out strikes as well (it seems to swell phenom ally fast )
I’ve debated sneaking down there after dark and pruning it myself. Instead I’m on the lookout for noticing a grounds crew working on the property to tell them what their tree has and what it is doing.
Scott
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Someone had said to spray with Immunox to help control it (but not eradicate it.) … at blossom time … too late for me. Anyone try this?
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I used to spray immunox in my summer spray sched. Every 3-4 weeks. As of last year I replaced Immunox with Indar and it seems to be keeping the black knot in abeyance. Only one outbreak on one branch so far. Fingers crossed that it continues. We have had nothingbut rain and humidity.
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In the Midwest Fruit Pest Management Guide for 2017 which just came out, they give treatment for black knot pg 63. Anyone do this???
https://ag.purdue.edu/hla/Hort/Documents/ID-465.pdf
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Patrick,
A few of us use Indar for pre harvest spray against brown rot. Mrs. G. posted above that she uses Indar for black knot, too.
I use copper hydroxide ( Kocide3000) at dormant spray. It must have helped as I have only a few small BK. I will use Indar at pre-bloom next year for better protection against BK.
I believe @alan, is the person who told us about the effectiveness of Indar. He may use Pristine as well.
Indar comes in a gallon size and is very expensive. Backyard growers like us do not need that much Indar. There is a recent thread titled “Wanting to buy Indar”. You may want to join them to split the cost. In your situation, You need such chemical.
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Thank You All