水稻穎枯病在長江流域各稻區均有發生,一般危害不太嚴重,但在個別年份和個別地區可能造成嚴重損失,發病輕的可使結實率下降10%、千粒重降低0.6-1克、稻穀減產5-8%,嚴重的減產幅度可達20%以上。
水稻穎枯病病菌隻侵害穎花和穀粒,尚未發現侵害其他部位和組織,在水稻抽穗後2-3周zhou危wei害hai幼you穎ying較jiao重zhong。病bing初chu在zai穎ying殼ke頂ding端duan或huo側ce麵mian出chu現xian淡dan褐he色se小xiao斑ban,逐zhu漸jian發fa展zhan為wei邊bian緣yuan不bu清qing晰xi的de橢tuo圓yuan斑ban後hou,病bing斑ban融rong合he為wei不bu規gui則ze大da斑ban,擴kuo展zhan到dao穀gu粒li大da部bu或huo全quan部bu,病bing斑ban中zhong央yang色se澤ze變bian淺qian,最zui後hou變bian為wei枯ku白bai色se,嚴yan重zhong的de變bian成cheng白bai穗sui,上shang麵mian生sheng有you許xu多duo小xiao黑hei點dian,即ji病bing菌jun分fen生sheng孢bao子zi器qi。穀gu粒li受shou害hai早zao的de花hua器qi被bei毀hui或huo形xing成cheng秕bi穀gu;乳熟後受害,米粒變小,質地變得鬆脆,品質下降;接近成熟時受害,僅在穀粒上有褐色小點,對產量影響不大。
水shui稻dao穎ying枯ku病bing病bing菌jun以yi分fen生sheng孢bao子zi器qi在zai稻dao穀gu上shang越yue冬dong,次ci年nian釋shi放fang出chu分fen生sheng孢bao子zi,借jie風feng雨yu傳chuan播bo,水shui稻dao抽chou穗sui後hou侵qin害hai花hua器qi和he幼you穎ying。水shui稻dao抽chou穗sui揚yang花hua期qi遇yu暴bao風feng雨yu。稻dao穗sui相xiang互hu磨mo擦ca造zao成cheng傷shang口kou,有you利li於yu病bing菌jun侵qin入ru。氮dan肥fei施shi用yong過guo量liang、施用過遲,植株貪青,成熟延遲,增加侵染機會。一般倒伏田地麵溫濕度高,有利於病菌孢子發芽侵入,病粒增多。冷浸田易發病。
防治水稻穎枯病主要應采取以下措施:yishijinxingzhongzixiaodu,xiaodufangfayufangzhidaowenbingxiangtong。ershijizaochulibingbigu,jiangdaibingbigugaowenduizhihuoshaozuohuifei,shamiebingjun。sanshijiaqiangfeishuiguanli,bimianpianshihechishidanfei,zengshilinjiafei;適時適度露曬田,使植株轉色正常,增強根係活力,防止倒伏;改gai造zao冷leng浸jin田tian。四si是shi在zai抽chou穗sui前qian後hou結jie合he防fang治zhi稻dao瘟wen病bing噴pen藥yao保bao護hu。發fa生sheng過guo該gai病bing的de老lao病bing田tian,應ying在zai始shi穗sui期qi和he齊qi穗sui期qi各ge噴pen一yi次ci藥yao,必bi要yao時shi在zai灌guan漿jiang乳ru熟shu前qian加jia噴pen一yi次ci。另ling外wai,還hai應ying在zai抽chou穗sui前qian風feng雨yu到dao來lai前qian或huo後hou噴pen藥yao一yi次ci,減jian輕qing發fa病bing。田tian間jian發fa病bing後hou,應ying選xuan用yong稻dao瘟wen靈ling等deng對dui病bing害hai有you治zhi療liao作zuo用yong的de藥yao劑ji,不bu宜yi選xuan用yong三san環huan唑zuo等deng保bao護hu性xing藥yao劑ji;也可以噴施30%氫氧化銅懸浮劑600倍液或77%可殺得懸浮劑800倍液。
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