一(yi)般甜(tian)菜(cai)(cai)發病(bing)(bing)(bing)后．植株矮(ai)小、葉(xie)(xie)片(pian)褪綠(lv)黃化，或(huo)呈黃褐(he)色卷曲干枯，或(huo)葉(xie)(xie)片(pian)無明顯癥狀(zhuang)但在炎(yan)熱天氣下植株葉(xie)(xie)片(pian)呈匍匐狀(zhuang)萎蔫。發病(bing)(bing)(bing)規律(lv)致病(bing)(bing)(bing)細菌(jun)在土(tu)(tu)壤或(huo)病(bing)(bing)(bing)殘(can)體上越冬。病(bing)(bing)(bing)菌(jun)都是從塊(kuai)根(gen)(gen)(gen)的(de)各類傷口侵(qin)(qin)入．在高濕(shi)條(tiao)件下擴展(zhan)引起塊(kuai)根(gen)(gen)(gen)腐爛。生長(chang)期間．借(jie)耕(geng)作、雨水(shui)和灌(guan)(guan)溉水(shui)傳播，引起重(zhong)復(fu)侵(qin)(qin)染。防(fang)(fang)治(zhi)(zhi)措(cuo)施(shi)農業防(fang)(fang)治(zhi)(zhi)選(xuan)用(yong)(yong)(yong)抗根(gen)(gen)(gen)腐病(bing)(bing)(bing)的(de)甜(tian)菜(cai)(cai)品種(zhong)。選(xuan)擇土(tu)(tu)壤肥(fei)沃(wo)、輪(lun)作時(shi)(shi)間長(chang)的(de)平地或(huo)地下水(shui)位低的(de)田(tian)塊(kuai)，避(bi)免重(zhong)茬(cha)(cha)和迎茬(cha)(cha)，注意(yi)深(shen)耕(geng)、深(shen)松土(tu)(tu)，及時(shi)(shi)中(zhong)耕(geng)，破(po)除土(tu)(tu)壤板結(jie)層。干旱(han)嚴重(zhong)時(shi)(shi)要及時(shi)(shi)灌(guan)(guan)水(shui)，可(ke)(ke)大(da)大(da)減輕根(gen)(gen)(gen)腐病(bing)(bing)(bing)。化學防(fang)(fang)治(zhi)(zhi)育(yu)苗時(shi)(shi)，用(yong)(yong)(yong)95％惡霉靈(ling)(ling)(ling)(土(tu)(tu)菌(jun)消)3kg／667m2拌細土(tu)(tu)30均勻(yun)撒在苗床上耙入土(tu)(tu)中(zhong)或(huo)施(shi)于溝中(zhong)。發病(bing)(bing)(bing)初期藥劑(ji)灌(guan)(guan)根(gen)(gen)(gen)。必要時(shi)(shi)噴灑(sa)或(huo)澆灌(guan)(guan)47％春(chun)·王銅(tong)(加(jia)瑞農)可(ke)(ke)濕(shi)性粉劑(ji)800倍液、95％惡霉靈(ling)(ling)(ling)(綠(lv)亨1號)精品3000倍液、3％惡霉·甲霜水(shui)劑(ji)(廣(guang)枯靈(ling)(ling)(ling))800倍液。8甜(tian)菜(cai)(cai)叢根(gen)(gen)(gen)病(bing)(bing)(bing)8．1為害癥狀(zhuang)該病(bing)(bing)(bing)基本(ben)癥狀(zhuang)為根(gen)(gen)(gen)毛(mao)壞死(si)，次生側(ce)根(gen)(gen)(gen)、根(gen)(gen)(gen)毛(mao)異常(chang)增(zeng)生或(huo)陸續壞死(si)．大(da)量次生側(ce)根(gen)(gen)(gen)和根(gen)(gen)(gen)毛(mao)成團集結(jie)，塊(kuai)根(gen)(gen)(gen)、側(ce)根(gen)(gen)(gen)剖面維(wei)管束有黃褐(he)色條(tiao)紋，且地上部癥狀(zhuang)多(duo)變。8．2發病(bing)(bing)(bing)條(tiao)件病(bing)(bing)(bing)株殘(can)體和病(bing)(bing)(bing)土(tu)(tu)是叢根(gen)(gen)(gen)病(bing)(bing)(bing)的(de)最主要侵(qin)(qin)染來源。8．3防(fang)(fang)治(zhi)(zhi)措(cuo)施(shi)避(bi)免重(zhong)茬(cha)(cha)、迎茬(cha)(cha)；選(xuan)用(yong)(yong)(yong)抗、耐病(bing)(bing)(bing)品種(zhong)；增(zeng)施(shi)有機肥(fei)；采(cai)用(yong)(yong)(yong)紙筒育(yu)苗移(yi)栽，以保證(zheng)移(yi)栽苗健壯(zhuang)無病(bing)(bing)(bing)；大(da)田(tian)用(yong)(yong)(yong)種(zhong)需加(jia)工磨(mo)光。

選用(yong)抗病(bing)(bing)(bing)(bing)品種，合理布局，清(qing)除田間雜(za)草，減(jian)少侵染來(lai)源。化學防(fang)治用(yong)8％菌克毒(du)克(寧南霉素)looo倍液或(huo)2病(bing)(bing)(bing)(bing)毒(du)A500倍液，輪換交替使用(yong)。加強(qiang)防(fang)蚜(ya)治蚜(ya)。可(ke)選用(yong)蚜(ya)虱(shi)凈、吡蟲(chong)啉、敵(di)殺死或(huo)其他菊酯類殺蟲(chong)劑(ji)。特別要重(zhong)視保護天敵(di)等消滅蚜(ya)蟲(chong)的(de)綜合防(fang)治方法。6甜菜霜霉病(bing)(bing)(bing)(bing)6．1為害(hai)癥狀甜菜在出苗(miao)后整個生(sheng)育期間均可(ke)發病(bing)(bing)(bing)(bing)，子(zi)葉、真葉及采種株地上器官均可(ke)被害(hai)，以(yi)幼嫩(nen)心(xin)葉發病(bing)(bing)(bing)(bing)最重(zhong)。葉片(pian)被害(hai)，初生(sheng)淺(qian)綠(lv)色不(bu)規則小斑，后病(bing)(bing)(bing)(bing)斑不(bu)斷擴大并變為淺(qian)黃色，最后病(bing)(bing)(bing)(bing)斑呈深褐色干枯。在潮濕(shi)條件(jian)下，病(bing)(bing)(bing)(bing)斑背面產生(sheng)初為白色、后為灰(hui)紫色的(de)霉層。病(bing)(bing)(bing)(bing)菌極易侵染生(sheng)長點而(er)引起(qi)系統發病(bing)(bing)(bing)(bing)，導致(zhi)幼嫩(nen)心(xin)葉褪(tun)綠(lv)、葉肉變厚、易碎，葉緣向下卷曲、畸形，嚴重(zhong)時心(xin)葉枯死。  

發病(bing)規律病(bing)菌(jun)在(zai)土壤病(bing)殘(can)體(ti)(ti)和種子上越冬，成為次(ci)年初侵(qin)染源。冷(leng)涼潮濕、多雨(yu)地區最(zui)適于甜(tian)菜霜(shuang)(shuang)(shuang)霉(mei)病(bing)的發生(sheng)。溫(wen)度l6℃左右，濕度70％以(yi)上最(zui)適于該病(bing)的流(liu)行(xing)。防(fang)(fang)治(zhi)措施(shi)(shi)：農業防(fang)(fang)治(zhi)嚴格檢疫；種檀抗病(bing)品(pin)種；實行(xing)輪作；增施(shi)(shi)磷鉀肥，不偏(pian)施(shi)(shi)氮(dan)肥；及時清除(chu)田間病(bing)殘(can)體(ti)(ti)，并在(zai)田外(wai)燒毀(hui)。化學防(fang)(fang)治(zhi)發病(bing)初期噴灑78％波·錳鋅(xin)(科博)可濕性粉(fen)(fen)劑(ji)500倍(bei)液或58％甲霜(shuang)(shuang)(shuang)靈·錳鋅(xin)可濕性粉(fen)(fen)劑(ji)500倍(bei)液或72％霜(shuang)(shuang)(shuang)脲·錳鋅(xin)(克露)可濕性粉(fen)(fen)劑(ji)700倍(bei)液，7~10d一(yi)次(ci)．連續防(fang)(fang)治(zhi)2~3次(ci)。甜(tian)菜根腐(fu)病(bing)為害癥狀(zhuang)·36·根腐(fu)病(bing)的癥狀(zhuang)因致(zhi)病(bing)菌(jun)種類不同而(er)異。