Apple tree damaged - wasps nest inside it- Chance to Save?

[J.M.]

The apple tree in my garden has been severely damaged by a hazel near it. I have cut back the hazel but the apple tree now only has one branch still alive. It also has a wasps' nest inside it. I'm not sure if using bug killer will finish off the tree... is there any hope?

[jdeb]

To be honest you might want to start again. You need to get rid of the wasps, and if they are IN the tree (as opposed to ON it) then it sounds as if it is old, has a hole in it an is therefore unhealthy.

If that is the case, I would take it (and the wasps) out.