Brought two patio apple trees, planted in containers in the spring,they have now developed brown spots on the leaves and some leaves have fallen off. Help needed to cure problem, would also like to know what causes it and how to prevent it.
It could be rust, but it could just be because we have had such a hot, dry period. Some trees do drop their leaves to cut their water losses. A crab apple in my garden has lost about half its leaves since we had the dry spell. Have you kept yours well watered?
Rust is just an fungus, I think, and you can get fungicides to prevent it.