Which sign is associated with Fire blight?

• A. Milky white bacterial ooze exuding from plant parts.
• B. Jellylike masses of orange Telia on evergreens.
• C. Velvety olive green spots on leaves.
• D. Brown cankers without ooze.

Answer: (A)

Fire blight is a bacterial disease, and its most recognizable sign is the milky white ooze that the bacteria exude from cankers, blossoms, or other plant parts, especially in wet weather. That ooze is rich with the pathogen and is a classic field indicator that points to fire blight more than any other sign.

The other signs belong to different diseases: jellylike orange masses on evergreens come from rust fungi, not fire blight; velvety olive green spots on leaves are typical of leaf spots or mildews caused by other pathogens; brown cankers that ooze are from canker diseases that aren’t the bacterial fire blight ooze. Without the milky bacterial ooze, you wouldn’t have the characteristic sign of fire blight.