Texas FFA Nursery Landscape Practice Exam

What is the primary time frame in which fireblight most affects susceptible plants?

1. In recently installed landscapes

2. In landscapes over four years old

3. During periods of rapid succulent growth

4. During the winter

The correct answer is: During periods of rapid succulent growth

The primary time frame in which fireblight most affects susceptible plants is during periods of rapid succulent growth. Fireblight, caused by the bacterium Erwinia amylovora, attacks young, tender shoots and flowers, which are particularly vulnerable when the plant is actively growing. This growth usually coincides with spring and early summer, when environmental conditions favor the proliferation of the bacterium. During these periods, warm temperatures and the presence of moist conditions can enhance the likelihood of disease spread. New growth is more susceptible due to its softness and high moisture content, making it an ideal target for the fireblight pathogen. Understandably, controlling fireblight requires attention to plant care and management especially in these growth phases to minimize the impact of the disease. In contrast, newly installed landscapes may not show symptoms immediately, as the plants may still be establishing roots and not yet exhibiting rapid growth. Plants older than four years could be less susceptible due to their mature tissue, which is often more resilient. Winter poses a dormant period for many plants, reducing vulnerability to active pathogens, making it an unlikely time for fireblight to affect them significantly.