  fire blight, also written fireblight, is a contagious disease affecting apples, pears, and some other members of the family rosaceae. it is a serious concern to producers of apples and pears. under optimal conditions, it can destroy an entire orchard in a single growing season. the causal pathogen is erwinia amylovora,type strain ncppb 683 a gram-negative bacterium in the family enterobacteriaceae. pears are the most susceptible, but apples, loquat, crabapples, quinces, hawthorn, cotoneaster, pyracantha, raspberry and some other rosaceous plants are also vulnerable. the disease is believed to be indigenous to north america, from where it spread to most of the rest of the world. fire blight is not believed to be present in australia though it might possibly exist there. it has been a major reason for a long-standing embargo on the importation of new zealand apples to australia. japan was likewise believed to be without the disease, but it was discovered in pears grown in northern japan. japanese authorities are however still denying its existence and the japanese scientist who discovered it is believed to have committed suicide after his name was leaked to affected farmers. ==symptoms== thumb|left|fire blight on a pear tree caused by erwinia amylovora fireblight is a systemic disease. the term "fire blight" describes the appearance of the disease, which can make affected areas appear blackened, shrunken and cracked, as though scorched by fire. primary infections are established in open blossoms and tender new shoots
Apple_tree_diseases Bacterial_tree_pathogens_and_diseases Enterobacteria Pear_tree_diseases