Fire blight

Fire blight is a devastating bacterial disease caused by the pathogen Erwinia amylovora. It primarily affects pome fruit trees, such as apples, pears, and quinces, as well as several ornamental plants within the Rosaceae family. The disease is highly contagious and spreads rapidly within susceptible orchards.

The most recognizable symptoms include the wilting and blackening of blossoms and young shoots, giving the tree an appearance of having been scorched by fire. Affected branch tips often curl into a characteristic hook shape known as a «shepherd’s crook». Under humid conditions, droplets of bacterial ooze may be visible on the infected tissue.

The pathogen thrives in warm, wet conditions during the spring flowering period. Transmission is primarily facilitated by honeybees and other pollinating insects, as well as splashing rain, wind, and contaminated pruning tools. The bacteria enter the tree through natural openings like flowers, stomata, or wounds in the bark.

The impact of fire blight is severe, as the bacteria can colonize the vascular system, leading to systemic infection. If left unchecked, the disease causes extensive necrosis of the bark and branches, eventually killing the tree. It represents a major challenge for commercial fruit production, requiring constant monitoring.

Effective management requires a combination of sanitation and chemical controls. Pruning out infected wood at least 20-30 centimeters below the visible symptoms is essential, along with disinfecting tools after every cut. Protective sprays containing copper or other approved bactericides during the bloom period are critical for preventing initial infections.