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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 apple and pear producers. 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.〔(【引用サイトリンク】title=Local apple producers say no to Kiwis' fruit )〕 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== 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 and leaves in the spring when blossoms are open. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fire blight」の詳細全文を読む スポンサード リンク
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