March again. I went out to do a walk-through and saw my old Italian Prune tree full of black knot. I’d pruned it all out (or so I supposed) in the fall. This is the best time to look for the stuff, when the branches are bare.
I think this one will have to go. Too bad, we love those plums.
That didn’t happen to my Italian plum in RI, but my two Mirabelles were destroyed by it. A horrible fungus!
I want to get rid of it before it infects other trees
Have at it because it is an air-borne spreader and it takes over trees quickly. Worst thing I had in my orchard!
knock on wood, i havent seen it on my trees yet. my property is ringed with pin/ chokecherry covered with it. 2 years ago i went around and cut off as many infected branches that i could. got to go check them again this spring. i have a fungicide maintenance spray schedule but want to keep it out if i can. 2 spring/ summer droughts in the last 2 years have helped.
Last year was droughty here, so I was surprised to see so much fungus all over the tree this spring
Likely the infections began the spring before (if the pedigreed gurus have it right). Do a good job of removal and you should enjoy the benefits of the droughty spring next season.
When I started growing plums here we had a several season string of droughty springs and I could easily grow plums even in sites well shaded from eastern sun, but the trend switched over to wet springs and it has been a constant battle ever since- depending on site. Variability of pressure is not always clearly based on environmental conditions. At least in ways I’ve managed to understand.
Like many of you I have tried several different plums and I have eliminated several because of their ease of getting black knot. As of now Spring Satin, Guthrie, Odon, Seedling, and AU Rosa hasn’t shown any signs of black knot. These are keepers unless I later have issues with them. Splash, and AU Cherry have only had one spot so as of now they are keepers. AU Rubrum has off and on had a few spots and I’m probably going to remove it completely.
@scottfsmith , are you still using a blowtorch on black knot? Do you have any new details on the the technique? Do you remove any of the knot before torching? Seems like it would be difficult judging when too much heat would destroy kill branch.
My recent method is to cut it all out and then blowtorch it. I got tired of not getting 100% success, but if I do both I never need to redo them. You also don’t need to torch it as much because you should have cut it all out so only the surface needs to be hit. I never killed a branch even when I didn’t cut it out first. If a branch is too small don’t bother with trying to cut it out, just remove it. Maybe 1" is about as small as I will keep. Look at the wood as you cut out the knot, the brighter green wood is the knot so get every bit of that bright green stuff until you hit the lighter green wood on all borders. Then give it the flambé treatment.