We have a cooking apple tree. It's old -quite possibly 58years old. It crops very well, We pruned it hard 3 years ago however one branch now needs chopping back by 2-3 feet as it's slowly pulling the tree over with the weight of fruit. Is it too late? Is there a danger of infection ? I don't want to kill the tree. Incidently any ideas how I can get some mistletoe to take on the tree?