In recent years homeowners have found the flowering crab an irresistible ornamental tree. Whatever the season, flowering crabs lend color and interest to our landscape. Spring flowers, summer foliage, fall fruits, and winter branch pattern and bark color create year-round interest. However, flowering crabs often turn unsightly as spring fades into summer and foliage becomes blighted with a common fungus disease called scab. Infected leaves may remain green or turn yellow, gray, or black.
Infected leaves drop early, leaving a sparse tree well into fall.
The disease seldom kills trees. Most older varieties of crabs, such as Hopa, are susceptible to the scab disease. During dry years, little scab prevails. Wet seasons may bring epidemics. Many new varieties are less prone to scab.