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四、常见的林木传染性病害上一讲谈到了林木的传染性病害是由众多的有害生物引起的。根据病原生物的类别,林木传染性病害又可区分为真菌病害、细菌病害、病毒病害、线虫病害及寄生性种子植物引起的病害等。其中,真菌病害约占林木病害的80％以上,是最重要的一类病害。我们将在本讲和下讲分别介绍各类病原生物及其所致的常见病害种类。 1.真菌及其所致的病害 (1) 真菌的一般概念真菌是一类没有叶绿素的低等生物,其营养体没有根、茎、叶的分化,一般为细丝,叫菌丝。真菌靠菌丝从其它活的生物或死的有机体吸取现成养料来生活,前
Fourth, the common disease of forest diseases The last talk about the disease of trees is caused by a large number of pests. According to the type of pathogen, forest disease can be divided into fungal diseases, bacterial diseases, viral diseases, nematode diseases and parasitic diseases caused by seed plants. Among them, the fungal diseases account for about 80% of the forest diseases, which is the most important type of diseases. We will introduce various types of pathogens and the types of common diseases they cause under this talk. 1. fungi and their diseases (1) the general concept of fungi Fungi is a class of lower organisms without chlorophyll, the vegetative body without root, stem, leaf differentiation, usually filaments, called mycelium. Fungi rely on mycelium from other living organisms or dead organisms sucked ready-made nutrients to live, before