Mulberry canker?
 

Hi.

I have a 7-year-old black mulberry tree that is suffering from bark splitting and dropping off. Initially I thought a deer might have nibbled it, but some of the worst affected areas are on major branches (rather than fresh young ones) and close to the trunk so not easy for a deer to get at. The tree is perhaps 7 feet tall. There are some buds and last year it suffered a lot of leaf and fruit loss, which I thought was down to not getting enough water in the summer.

I have three questions:

1. Is it canker or could it be something else?

2. How do I treat it and dispose of the chopped off material? If it's canker and some of the major branches are affected, should I saw off those branches now or wait? Or chop down the whole tree? (Some, not most, of the tree is affected.) Should I burn the cut off branches? And what do I apply to the sawn areas of the tree to seal them from further infection?

3. It is perhaps 50 yards from my apple trees. If it is canker, are they at risk too, and what can I do to prevent infection?

All suggestions gratefully appreciated!