Any idea what plum disease this is?

[Mickster]

Thanks fruitnut. I just read through the following thread [1] Scott started. If these are at the base of a large branch do I need to cut the entire branch out or can I just cut out the black knot with a knife? Also, would you recommend that I order some chlorothalonil and spray the tree? Man disease sucks.

[1]

Dealing with severe black knot

Shiro and Satsuma have exact same susceptibility in my nursery and elsewhere as most other plums I grow. I get a pretty good chance to evaluate the plums I grow because I spread my nursery trees in various spots as far as eastern exposure and I have about 30 trees each of those two varietes. I also manage about a score of Shiros at that many different sites. Satsumas are newer for me so I’m managing half as many on smaller trees in various orchards. As I have stated often, the only extreme …