Need help! What is this?

[DCash67]

View attachment 32976

View attachment 32977

View attachment 32978

This is currently on my Flowering Crab and now seems to be showing up on my Flowering Pear......any suggestions what it may be and how to get it under control?

Thanks

 

[treeseer]

Looks like this, http://www.extension.umn.edu/yardandgarden/ygbriefs/p417blackknot.html

but pears are in a different genus and I've never seen it in pears.

Prune it out, now.

 

[Tree Wizard]

I agree - black knot. Plus I believe the tree is a flowering plum, not a crab. I also believe that tree is too far gone to be saved long term - maybe even short term. When you catch the first few "knots" you can kind of keep it under control for quite a while, but eventually the tree will go.