We have seen some tip dieback recently in crabapples, particularly with 'Indian Summer' and to a lesser degree on 'Donald Wyman'. Leaves in the affected area may distort or curl. In some cases scarlet-to-purple leaf discoloration is present on both sides of the leaf sometimes with necrotic centers. The tips become dessicated and sunken, dying back completely in some plants. The nearly uniform field pattern suggests an abiotic cause and potentially a time-limited factor. Current speculation - cultivar sensitivity to heat?
Dogwood leaf scorch
Dogwood leaf scorch can also be caused by heat. For more information on this disorder click the link.
This image of dogwood leaf scorch was taken on May 21, 2007. For more information on dogwood leaf scorch, click the link for the Online Guide to Plant Disease Management section on this disorder.