Devon,
United Kingdom 
Russet apple tree problem. This is a mature tree which had a lot of blossom, but during the past month the leaves turned brown and fell off completely on one side, the other side has mottled brown leaves and I have very little fruit. This is obviously a bug problem of sorts but when should I spray the tree to avoid the same next year?
10 Sep, 2015
Answers
Thanks very much for this - really helpful.
10 Sep, 2015
Not necessarily a bug problem, sounds more like an infection in the tree, possibly at the root. Inspect the whole tree (or as far up as you can go), starting at the base of the trunk, all round. You're looking for soft spots, weeping, split bark, discoloration, anything you can see that shouldn't be there.
10 Sep, 2015