Fireblight is one of the most dangerous bacterial plant diseases, and may affect members of the rose family (Rosaceae) such as apples, pears, cotoneasters, hawthorns and pyracanthas. The term 'fireblight' describes the appearance of the disease, which can make affected areas appear blackened, shrunken and cracked, as though scorched by fire. The first sign is the browning and withering of foliage, which does not fall, but instead remains clinging to the plant. Oozing cankers appear on the branches, and the whole tree may eventually die within a few years.

Fireblight is caused by the bacteria Erwinia amylovora, which is produced from the cankers and spread by wind, rain, birds and insects. The plant becomes infected through injuries or natural entry points such as flowers, from which the pathogen spreads quickly throughout the rest of the plant via the plant's vascular system, eventually reaching the roots of the plant. Once the roots are affected, the plant will usually die.

Control

Infected areas should be removed by pruning, making sure that any cuts are approximately 60 cm (2 ft) into healthy wood; that is, beyond the reddish internal staining that indicates the infection. Any pruning equipment should be disinfected between each cut with Jeyes Fluid or methylated spirits to prevent the spread of the bacteria. If the plant is small, or the infection is severe, it is usually best to dig it up and destroy it.