Why do the leaves on my older apple trees have brown spots and are falling off?

September 13, 2024 Ask the Expert, Fruit Trees and Small Fruits, Managing Insect, Diseases, and Animal Pests

Question:

My Granny Smith Apple tree has been losing leaves leaving the bottom half of the tree leafless. The leaves have brown spots on them and I can see them dropping off when a squirrel jumps on a branch or a breeze blows through. It has been many years without getting pruned, but has born fruit for many years. I planted it about 40 years ago. It has apples on it now but they are smaller for this time of year. I am afraid it may be sick, neglected or on its last legs, but I would love to save it.
Answer:
Jonathan Foster, Home Horticulture Outreach Professional

If the tree is 40 years old and hasn’t been maintained according to best practices protocol, it could be approaching its productive lifespan. That said, apple trees can live and be productive for far longer, so I wouldn’t give up on it without trying a few things first–many old apple trees can be rejuvenated with a bit of effort and it is producing fruit, which is a good sign. The tree is definitely in need of pruning, which can affect flower and fruit production, so I would start there (there is a nice video in that link showing our fruit specialist, Dr. Renae Moran, working an apple tree). I think you may also have apple scab going on the tree, which is a common fungal condition in apples, especially during hot, wet weather like we’ve had the last two summers. Pruning out unnecessary and/or dead growth will help mitigate that, as will promptly removing any debris (including fruit) that falls to the ground, as many fungal pathogens overwinter on such detritus. It’s probably also worth getting your soil tested through the UMaine Analytical Soil Lab–you can note that the space is for growing apples and they can give you recommendations on any amendments that might be advisable.

If things don’t improve next season after these efforts, let us know and we can see if there is anything else to be done.

Happy gardening.