Make sure you plant your tree at a well-drained location to start.
Several fungal diseases can cause apple trees to lose their leaves. Apple scab causes olive green or black spots on the leaves. Leaves eventually drop from the tree. Rust causes orange spots on the leaves. The infested leaves will eventually drop from the tree.
The alternate host for this tree is the evergreen red cedar (Juniperus virginiana). This may have been the"pine tree" your experienced gardener was. Jun 29, By the beginning of June, they begin to fall off while still a discolored green or they shrivel up while on the tree branch and then fall to the ground.
This begins first on the lower leaves and then extends up to the canopy. New growth will appear but generally dries and shrivels before falling. Jun 18, This natural reduction in crop size is called “June drop” and occurs either as suggested in June or late May and peaks about 8 weeks after flowering in early July.
Both apples and pears are prone to June drop. If the weather is cool and wet, June drop can be quite large and last quite a while.