Fireblight

Fire blight is a bacterial disease affecting apple, crabapple, pear, hawthorne, pyracantha (firethorn) and related species. The bacteria commonly live over winter in cankers (old diseased areas) in the tree, from which they ooze in early spring. The bacteria usually are spread from the cankers by insects and by wind-blown rain. Sometimes careless pruning practices also may spread the bacteria.

Fireblight