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农田里每一种农作物都有若干种病害。我们经常碰见的小麦叶上长黄疸、麦穗变成黑穗、玉米植株上生灰包、棉花发生萎蔫枯死等,都是农作物生了病的表现。生病的病原物简称病原。原病包括能传染的和不能传染的两大类。干热风危害造成的青干,冻害造成的枯苗,缺铁造成的白化等,没有传染性;而小麦的黄疸、玉米的灰包等,都是由于传染发生的。所以有传染性。可以传染的病原一般是生物性的,有生命,所以也有死亡,我们叫它做病原物。只有活着的病原物才具有传染性。
Every crop in the farmland has several diseases. We often meet the wheat leaves jaundice, ears into black ears, corn plants gray packets, withered wilt cotton, etc., are the performance of crops sick. Sick pathogen referred to as pathogen. The original disease includes both infectious and non-infectious categories. Dry and hot wind damage caused by green stems, frost damage caused by the dry seedlings, iron deficiency caused by albino, not contagious; and wheat jaundice, corn gray packets, etc., are due to infection occurred. So contagious. Infectious pathogens are generally biological, there is life, so there are dead, we call it a pathogen. Only living pathogens are contagious.