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一、苗病发生的一般况几年来,关中地区棉区苗病害早春流行相当普遍,由于病害发生的时间短,病势发展快,所以为害性往往是严重的。在1955、1957、1958年苗病猖獗成灾,引起棉田翻种者为数甚广。以1957年为例,关中各县翻种面积达100万亩以上,而且缺苗亦很严重。棉苗病害的发生和流行与早春气候条件的关系甚密,一般在棉苗出土前,或刚露头的幼苗,突然遇到低温高湿的环境,为病菌侵染棉苗创造了有利条件;但是各年播种期的气候有所不同,苗病发生的时间及严重程度也不一致。因此,苗病的发生规律,尚有待深入研究。据1955—1959年各县的资料报导,盩厔、乾县、三原、泾阳、高陵、长安、渭南、兴平、武功、华县、华阴等十二县苗病发病较重,常年死苗达15—20％,严重达80％以上;
First, the general situation of seedling disease In recent years, Guanzhong area cotton seedling disease early spring epidemic is quite common, due to the short duration of the disease, the rapid development of the disease, so the damage is often serious. In 1955, 1957, 1958, the disease was rampant and caused a great number of cotton seedlings. Take 1957 as an example, Guanzhong counties have an area of more than 1 million mu, and the lack of seedlings is also very serious. The occurrence and prevalence of cotton seedling disease are closely related to the climates of early spring climatic conditions. Before the emergence of cotton seedlings or the newly emerged seedlings, they suddenly encounter the environment of low temperature and high humidity, creating favorable conditions for the infection of cotton seedlings by germs. However, The climate at planting seasons varies from year to year, and the timing and severity of seedling diseases are also inconsistent. Therefore, the occurrence of Miao disease has yet to be further studied. According to the data of counties from 1955 to 1959, the incidence of Miao disease in 12 counties such as Qionglai, Qianxian, Mianyuan, Jingyang, Gaoling, Chang’an, Weinan, Xingping, Wugong, Huaxian and Huayin were relatively heavy. Up to 15-20%, severe up to 80% or more;