Apple scab is the most consistently serious disease of apple and flowering crabapple in Kentucky. This disease also occurs on hawthorn and mountain ash; a similar disease affects pear and pyracantha (firethorn). The most noticeable losses on apple result from reduced fruit quality and from premature drop of infected fruit. Scab also causes a general weakening of the host when leaves are shed prematurely. Summer defoliation of flowering crabapple due to scab invariably results in fewer flowers the next spring.