The bark of old fruit trees harbour all sorts of pests in their crevices. There is a simple way of getting rid of the spores of illnesses, eggs and larva of parasites who find a nice warm nest in the crevices during the winter. Use a soft brush that can enter into the crevices and removes the unwanted. Don't forget to spread a cloth around the tree to pick up the waste. After this treatment the bark will look much healthier, and less prone to illnesses during the year.
Don't put your harvest of undesirables on the your compost!