Certified Arborist Practice Test

Fire Blight is a disease primarily caused by the bacterium Erwinia amylovora. This organism primarily affects plants in the Rosaceae family, particularly apple and pear trees. The bacterium infects the flowering parts and shoots of these trees, leading to characteristic symptoms such as blackened shoots and blossoms that appear as if they have been scorched by fire. Understanding how Fire Blight operates requires knowledge of how bacteria can spread and infect plant tissues. Unlike fungi or viruses, which have different modes of infection, bacteria like Erwinia amylovora rely on water for movement and can spread rapidly during rainy conditions or through splashing water. Bacterial infections can lead to significant damage and economic loss in orchards if not managed properly, emphasizing the importance of recognizing and diagnosing this pathogen accurately in arboriculture practices.