Fire Blight (Erwinia amylovora) in the Low Desert

HOST: Found primarily on fruits such as apple, pear, pyracantha, etc.

SYMPTOMS:

• Blossom blight - blooms look water-soaked, sunken & discolored, bloom cluster hooks downward

• Twigs begins to die back from the tip. Leaves and bark have a scorched appearance.

• Later in the season both small and large branches die from cankers in the bark. The bark is killed and the cambium discolored. A milky exudate oozes out of the canker. As soon as the branch or limb is girdled, it dies quickly.

• Eventually, if left unchecked, it will spread to the main trunk and kill the tree.

CAUSE:

The bacteria is spread by rain water, irrigation, insects, and people (via infected tools).

MANAGEMENT:
Prevention

• Select resistant varieties
• Do not over fertilize - succulent growth is very vulnerable
• Avoid wounding trees which provides an entryway for the bacteria

Treatment

• Remove infected branches as soon as they are noticed at least 12 inches below any visible damage. Dispose of cuttings carefully to prevent the spread of disease. Disinfect tools after each cut.

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