what is the tree... i am guessing prunus ...

if so.. frankly .... i consider it untreatable ... its endemic to the family ... and you can waste a lot of money, time and chemicals.. trying to fix it.. and never do so ... [though there are a lot sellers willing to sell you all the goo you want]

it could take decades for the tree to fail ... or not.. who knows ...

but it usually boils down for me.. to spending say $100 to TRY TO CURE IT...

or spending $30 to replace it.. if and when it ever does fail ... or better yet.. choosing something outside the family ... and avoiding it completely ...

another option is to spend the money on a replacement of some other type.. now... and when the time comes.. simply remove this one ... this way.. your replacement has a leg up on the process and you wont have a big hole in your landscape ...

pic of the whole.. and an ID .. if you want more than speculation ...

ken

There appears to be a double callus so it may be trying to fight off what appears to be canker but need to accurately diagnose. Thought I give it a shot on this forum before having a tree company come over to evaluate.

I was focusing on a diagnosis (or key things to look for) not an action plan on treatment or replacment. One item I plan to look for this summer is any amber colored ooze.

Sorry, thought I bump this up once as it was bumped down without the question being answered.

Usually you'll see more sunken tissue if its Canker. However something doesn't look right with the damaged tissue. Can't say for sure what it is.