Yes, this does appear to be black knot disease. You can read some further information on the link provided. There isn't a chemical spray to effectively control it so if you can prune out the areas that you see, it can help control the spread. 

This appears to be possibly be a native black cherry tree. If you can't safely reach the canopy to prune you may want to reach out to a certified arborist for assistance. 

If you have further questions with it, please contact us again. 

Emily.