Fire Blight

Pathogenic bacterial disease effecting many fruit bearing trees, dispersing through the tree’s vascular system

Latin Name

Erwinia amylovora

Trees Affected

Rose family, apple, pear, crabapple, serviceberry, conoeasters, hawthorns, quinces, pyracanthas, blackberries, raspberries, mountain ash

Threat to Trees

Moderate to Severe


Sporadic but severe bacterial oozing cankers which remain present indefinitely after contamination


Honeybees and other insects attracted by bacterial ooze can transmit bacterium. Splashing rain, wind and contaminated pruning tools are also cause.

Signs & Symptoms

Dark, watery, oozing cankers on branches, twigs, and trunk. Cankers are often small and difficult to notice. Fruit loss or discoloration occurs relative to disease severity. Open flowers are often the most common infection site, and often appear blackened. Occasionally, branches and twigs will become blackened, giving the tree a scorched or “fire” appearance.


Bacteria overwinters in blighted branches at the edge of cankers, then rapidly multiplies in temperate weather. Bacteria is forced through cracks and bark pores, killing the cambial tissue of branches, flowers, and fruit above the girdled area.

Domestic Origins

North America, spreading to most of the world with the believed exception of Australia

Geographic Location

Heavy Northeast presence, but found throughout US

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