Alternaria blotch
Disease
Alternaria blotch
Alternaria mali Roberts
Distribution: An increasing problem in the eastern North America, but has yet to be found north of Virginia.
Photos
Damage can be confused with injury from the fungicide Captan (shown here).
Mid-Atlantic Orchard Monitoring Guide
D
The disease primarily affects the foliage, causing circular, necrotic lesions with a light brown interior (A) that later become surrounded by a darker purplish halo (B). Defoliation can occur by late summer on susceptible varieties that are heavily infected (C). The pathogen can also attack green, woody tissue, but it rarely attacks the fruit.