Fireblight is a potentially fatal disease of trees and shrubs of the sub-family Pomoideae (those of the Rosaceae family with apple-like fruits). Common hosts in Britain are Hawthorn, Apple, Pear, Whitebeam, Cotoneaster and Pyracantha. The disease is caused by the bacterium Erwinia amylavora which originates from the USA and was first recorded in Britain in Kent in 1956. The disease can cause significant losses in orchards and nurseries where large numbers of trees can be killed in local outbreaks and cropping of more resistant species seriously reduced.
The bacteria quickly multiply and spread to kill the inner bark of shoots and spurs, spreading into branches and even the stem, causing cankers and death of bark. If branches or stems are girdled by the infection, the branch or tree will die. The blackening of flowers and leaves can have the appearance of being scorched by fire, giving the disease its name.
The disease cannot be cured but the spread of infection can be stopped by pruning out infected branches. These should be cut well below the last sign of staining and in dry conditions. Pruning tools should be swabbed with methylated spirits between every cut. Infected material should be promptly burned.