Georgia Pesticide Applicators Practice Exam

What is a characteristic symptom of Fireblight in plants?

1. Yellowing of leaves

2. Root rot

3. Twigs dying back from the terminal end

4. Wilting of flowers

The correct answer is: Twigs dying back from the terminal end

Fireblight is a bacterial disease caused primarily by Erwinia amylovora, which affects various plants, especially those in the Rosaceae family, such as apples and pears. A characteristic symptom of this disease is the dieback of twigs, specifically starting from the terminal ends. This symptom is often associated with a distinctive “shepherd's crook” appearance, where the tips of the affected branches bend downwards. As the bacteria invade the plant, they cause a rapid decline in the health of the twigs, leading to their death while the rest of the plant may still appear relatively healthy initially. This aggressive dieback is crucial for identifying Fireblight, distinguishing it from other diseases or conditions that may not show such specific terminal dieback. In contrast, yellowing of leaves, root rot, and wilting of flowers are symptoms associated with other plant stresses or diseases. Leaf yellowing can indicate nutrient deficiencies or other stresses, root rot typically results from overwatering or poor drainage leading to fungal infections, and wilting flowers may relate to water availability or physiological stress, rather than the specific symptoms of Fireblight.