一、症狀識別 在棉苗出土前,常侵染幼根、幼芽,造成爛芽、lanzhong。chutudemianmiaoshouhaihou,zuichuzaijindimiandejingjibuchanshenghuanghesebandian,zhihouzhujiankuoda,chanshengaoxianneisuo,aoxianbuyinshishuiguoduoerchengyisuozhuangbianxi,zuihoubianchengheihesebingqiefulan,mianmiaokuweiganku,henyicongtuzhongbachu,zheshigaibingdezhuyaotezheng。
二、流行特點 該gai病bing病bing菌jun以yi菌jun絲si體ti或huo菌jun核he在zai土tu壤rang中zhong或huo病bing殘can體ti上shang越yue冬dong,在zai土tu壤rang中zhong形xing成cheng的de菌jun核he可ke存cun活huo數shu月yue至zhi幾ji年nian。立li枯ku病bing的de初chu次ci侵qin染ran主zhu要yao來lai自zi土tu壤rang,帶dai菌jun種zhong子zi也ye可ke傳chuan染ran。棉mian苗miao未wei出chu土tu前qian,立li枯ku絲si核he菌jun可ke侵qin染ran幼you根gen和he幼you芽ya,造zao成cheng爛lan種zhong和he爛lan芽ya。棉mian苗miao子zi葉ye期qi最zui易yi感gan病bing,棉mian苗miao出chu土tu的de1個月內如果土壤溫度持續在15℃左zuo右you,甚shen至zhi遇yu到dao寒han流liu或huo低di溫wen多duo雨yu,立li枯ku病bing就jiu會hui嚴yan重zhong發fa生sheng,造zao成cheng大da片pian死si苗miao。若ruo收shou花hua前qian低di溫wen多duo雨yu,棉mian鈴ling受shou害hai,病bing菌jun還hai可ke侵qin入ru種zhong子zi內nei部bu,成cheng為wei下xia一yi年nian的de初chu次ci侵qin染ran源yuan。播bo種zhong過guo早zao、氣溫偏低、棉種萌發晚、出苗慢、病菌侵染時間長的地塊發病重。多年連作棉田發病重。地勢低窪、排水不良和土質黏重的棉田發病較重。
三、防治方法
1.nongyefangzhi。zaixuanyongkangbingpinzhonghezhongzibaoyidejichushangjiaqiangmiaoqiguanli。mianmiaoxianxinghoujikaishizhonggeng,yuhougengyingjishizhonggeng,yijiangditurangshidu,tigaodiwen。rumianmiaokaishifabing,ketiejinbomojiashenzhonggeng , 使 土 壤 通氣 、 散 墒 、 增溫,促使病苗盡快長出新根,棉苗長出3~4片真葉,莖部逐漸木質化,可抵抗病菌侵染。如已有死苗,可在死苗處噴灌0.1%的高錳酸鉀水,減少病菌傳播。並適時早間苗,及時拔除病苗。注意不要過早揭去地膜晾墒,否則夜間低溫不利於緩解病情。
2.藥物防治。①噴霧。發病初期,用10毫升適樂時或適麥丹+5毫升愛多收或申嗪黴素15毫升+15毫升海綠素對一桶水(15公斤),順棉苗主莖噴霧,使藥液順主莖滴入土壤,連噴2~3次,間隔期10~15天,對於防治棉花苗期立枯病有特效。②灌根。發病初期,用15毫升申嗪黴素+15毫升海綠素+20克磷鉀動力對一桶水灌根,連灌2~3次,間隔期5~7天。③塗刷。用10毫升適樂時或適麥丹+5毫升愛多收或15毫升申嗪黴素+15毫升海綠素,對0.5公斤水,扒開棉棵周圍的土使其露出病斑,用毛刷塗刷,連續塗刷2~3次,間隔期7~10天。
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