Several customers have asked:

Why have my apple tree's leaves turned yellow and are prematurely dropping?

Chris replies:

A number of questions today concerning yellowing leaves and premature leaf drop on apple trees. Apart from drought (root stress) the most likely reason is Apple Scab disease. If your fruits are showing the distinctive marks as per the photo, then this too is scab. Some varieties are more prone to it than others.

A fungicides containing myclobutanil - Bayer Garden Systhane Fungus Fighter - can give good control when used according to the schedule recommended by the manufacturers.

For the most effective control, you need to cover the whole tree. Unfortunately, most gardeners will not have sprayers capable of treating large, old trees.

Apple scab - photo credit: RHS