Garden Q&A: How can I combat the fungus that attacks my apple trees every year?

Good hygiene and airflow is key to tackling apple scab, a common fungal problem in warm and damp climates like ours, writes Peter Dowdall .File picture
I have two miniature sweet apple trees, which every year are pitted by some fungus. Is there anything I can do to get rid of the problem? I would appreciate your help.