Fire blight

The disease primarily affects members of the Rosaceae family. Most notable hosts include apples, pears, quinces, and ornamental shrubs like firethorn and hawthorn. The bacterium is highly contagious and can be spread across large distances, often compromising both commercial orchards and residential landscapes.

Symptoms are distinct and often resemble fire damage. Early signs include wilting of blossoms and young shoots, which subsequently turn dark brown or black and shrivel. A classic symptom is the curling of the shoot tip into a shape known as a shepherd's crook. In humid conditions, creamy-white or amber bacterial ooze emerges from the bark.

Disease development is highly dependent on environmental conditions. Warm, wet weather during the blossoming period is ideal for infection. The bacteria spread via splashing rain, strong winds, and insect vectors such as bees. The pathogen survives the winter in cankers on the main branches or trunks, emerging again when temperatures rise in spring.

Effective management requires an integrated approach. Cultural practices include pruning out infected branches several inches below the visible lesions and disinfecting tools with alcohol or bleach. Chemical control involves applying copper-based sprays or specific antibiotics during the bloom phase to prevent the colonization of flowers by the bacteria.