I have a mature yellow plum tree which in recent years has been developing a problem causing the fruit to malform soon after forming. The problem has inreased over the last ten years. When the fruit is near ripening late July 50 percent of the remaining non deformed plums rot on the tree resulting in a loss of most of the crop. The trouble has only started in recent years I never had the problem originally. I haven't been able to obtain any help from various garden centres, any answers.

Tom