最近十多年来,湖南省由于耕作制度的改变,双季稻、三熟制面积的不断扩大,随之而来的水稻早播早植以及矮秆多穗型品种的推广,和多肥密植的栽培,稻谷的产量有很大的增长,但病虫的种类和为害程度也发生了变化。有些病虫由次要的或不重要的上升为主要的,发生的频率也增加了。历史上在湘西、湘南山区发生的稻瘟病,仍为那些山区的主要病害, In the recent ten years, due to the change of farming system in Hunan Province, the continuous expansion of double-cropping rice and three-cropping system, the ensuing early planting and early planting of rice and the popularization of dwarf and multi-spike varieties, The output of paddy has greatly increased, but the types of pests and diseases and the degree of damage have also changed. Some pests are secondary to minor or insignificant increases, and the frequency of occurrence increases. The history of rice blast in the western Hunan and southern Hunan mountains is still the major disease in those mountains,