We have a mature cherry tree in the backyard and this year it produced copious flowers and many young fruit, but they fell off day by day. When the normal time for ripening came, there were only a few cherries on the tree and the rain left nearly all of them diseased by some kind of fungus. The leaves looked either wilted and rusty or were full of holes. Over the summer they have fallen off bit by bit until now the tree looks as it normally does in October. The tree is well over 30 years old, so I suspect it’s probably succumbing to old age. Is that correct, you think? See attached photos.
Thank you for contacting Toronto Master Gardeners.
It is heart breaking to have a mature tree shows signs of disease. Cherry trees are in the Prunus family along with plums. It is a massive family of plants with a large list of potential causes for leaf loss. To assess what caused the leaf loss one needs to inspect the tree closely for any signs of insects as well as inspecting the branches and trunk for any signs of damage to the bark. You may find areas that look diseased and you may find spots with exudates, or seeping fluid, on the bark. It is important to gather all possible information before diagnosing the problem.
Your best bet is to have a certified arborist come and inspect your tree. They should be able to narrow down the possible causes and suggest what management plans are open in your situation. Here are two links that will help you find a certified arborist in your neighbourhood.
Landscape Ontario https://landscapeontario.com/
Ontario Commercial Arborists Association https://www.isaontario.com/content/ocaa
I am also attaching some links below that touch on some of the diseases Cherries can display.
Good luck and I hope you can find a way to save your tree.