Figure 2 . Fireblight on trunk of English hawthorn. Fireblight affects a wide range of rosaceous plants including apple, flowering crab, pear, firethorn, hawthorn, cotoneaster, quince, and mountain ash. Although fireblight can be a devastating disease, it is not as common in Kansas as scab and cedar-apple rust. Symptoms of fireblight are most noticeable in the spring on blossoms and succulent new growth.
Infected blossoms become water-soaked and turn dark green or brown.
Young, infected shoots rapidly wilt as if scorched by fire. The terminal end of the diseased shoot becomes hooked and is commonly referred to as a shepherd's crook. During wet weather, small droplets of amber-colored ooze containing millions of bacteria can be seen leaking from infected tissue. After initial infection of the shoots, the bacterium may move long distances within the living tissue and kill large portions of the tree. Infected areas of the bark on branches and trunks become slightly depressed and darker in color than surrounding healthy bark.