What is the key symptom of cankers caused by Bacterial Fire Blight?

The key symptom of cankers caused by Bacterial Fire Blight is indeed characterized by dark streaking of the wood. This condition manifests when the bacteria invade the plant's vascular system, resulting in necrotic tissue. The dark streaks indicate that the internal tissue is dying, which significantly hampers the plant’s ability to transport water and nutrients.

Recognizing this symptom is essential for diagnosing Bacterial Fire Blight early, as it can lead to serious damage or death of the affected plant, particularly in plants like apple and pear trees. Managing this disease effectively often requires timely removal of infected branches and proper sanitation measures.

Other symptoms, such as brown spots on leaves, may suggest different types of plant diseases and are not specific to Bacterial Fire Blight. Dusty powder on foliage is typically associated with fungal infections like powdery mildew. Swelling of plant roots may indicate issues such as root rot or nematodes, rather than the specific cankers associated with Bacterial Fire Blight. Understanding these distinctions is crucial for effective plant care and disease management.