Which bacterial pathogen is associated with fire blight?

Fire blight is a serious disease primarily affecting fruit trees, especially those in the rose family such as apples and pears. The disease is specifically caused by the bacterial pathogen Erwinia amylovora. This bacterium enters the plant through blossoms and young, succulent tissue, causing the characteristic dieback symptoms associated with fire blight.

Erwinia amylovora produces enzymes and toxins that lead to the rapid decay of the plant tissue, producing a distinctive blackened appearance on branches and blossoms, which is indicative of the infection. Its ability to thrive in wet conditions and its capacity for rapid spread during warm spring weather make it a significant concern for orchard management.

While other options represent different types of bacteria, they are associated with other plant diseases or conditions. For instance, Pseudomonas species can cause a variety of plant diseases but are not specifically linked to fire blight. Agrobacterium species are known for their role in plant tumors and galls, while Clavibacter species are generally associated with various bacterial wilts and rots, but not fire blight. Therefore, the correct identification of Erwinia sp. is critical in understanding and managing the disease effectively.