Upon close inspection of the underside of symptomatic leaves, if cupping is due to aphid feeding, the aphids or cast skins should be visible. If you're getting calls from panicked home fruit growers saying all the little fruits are dropping from their trees, chances are good that the plants are simply shedding excess fruit. Most trees set many more flowers than needed for a full crop, especially following a relatively mild winter. Only 1 bloom in 20 is needed for a good crop on a full-blossoming apple tree. Although the mass dropping of small fruit in June can be alarming, its just nature's way of thinning the crop so the remaining fruit can reach full size.
Most fruit trees have at least two waves of fruit drop.
The first occurs shortly after bloom. Lack of or incomplete pollination usually causes this drop. The second drop occurs 3-4 weeks later. Competition among the fruits for water and nutrients is thought to be the cause of June drop. Fruits that contain the fewest or weakest seeds are usually the first to drop.