Certified Arborist Practice Exam

Fire Blight is a disease caused by a:

1. Nematodes

2. Phloem

3. Bacteria

4. Allelopathy

The correct answer is: Bacteria

Fire Blight is indeed caused by bacteria, specifically the bacterium Erwinia amylovora. This disease primarily affects plants in the Rosaceae family, which includes fruit trees like apples and pears. The bacteria infect the blossoms, shoots, and branches, leading to symptoms like wilting, browning, and dieback of infected tissues, resembling scorch or burn, which gives the disease its name. Understanding the biology of Fire Blight and its causative agent is essential for effective diagnosis and management in arboriculture. Recognizing that it's a bacterial infection helps in developing appropriate control measures, such as pruning infected branches and using resistant varieties. Knowing that this disease is not caused by nematodes, phloem conditions, or allelopathy is also important for distinguishing between different plant health issues and ensuring the right treatment strategy is employed.