Curling Apple Leaves
Each season, the leaves on my five year old Jonagold apple tree curl upward noticeably. I have a Fuji and a Gravenstein that display the same tendency, but to a lesser degree. The tree bears some fruit, but the quality could be better. Adjusting the water regimen doesn't affect the condition. I've also looked for signs of powdery mildew, but I don't see white patches on the upper surfaces of any of the leaves (and it's always been my understanding that the white fuzziness on the undersides of the leaves is normal).
Until just recently, I never sprayed the tree with anything. This season though, with all the late rains we received in Northern California, I believe the tree is suffering from a case of apple scab. For the first time, the fruit has black spots all over them. I applied my first treatment of Neem oil this past weekend. I will continue to apply Neem oil weekly for the next several weeks.
Assuming that the Neem oil treatments don't suddenly cure the curling problem, I am curious whether anyone has faced the condition before and found the key to remedying it?