褐斑病在紫薇生長季節常常發生。褐斑病發生嚴重時常常會導致植物葉片大量枯黃、脫落,影響觀賞和開花。
紫(zi)薇(wei)褐(he)斑(ban)病(bing)的(de)病(bing)原(yuan)菌(jun)是(shi)一(yi)種(zhong)真(zhen)菌(jun),主(zhu)要(yao)侵(qin)害(hai)葉(ye)片(pian),並(bing)且(qie)通(tong)常(chang)是(shi)下(xia)部(bu)葉(ye)片(pian)開(kai)始(shi)發(fa)病(bing),後(hou)逐(zhu)漸(jian)向(xiang)上(shang)部(bu)蔓(man)延(yan)。發(fa)病(bing)初(chu)期(qi)病(bing)斑(ban)為(wei)大(da)小(xiao)不(bu)一(yi)的(de)圓(yuan)形(xing)或(huo)近(jin)圓(yuan)形(xing),為(wei)紫(zi)黑(hei)色(se)至(zhi)黑(hei)色(se),邊(bian)緣(yuan)顏(yan)色(se)較(jiao)淡(dan)。隨(sui)後(hou)病(bing)斑(ban)顏(yan)色(se)加(jia)深(shen),與(yu)健(jian)康(kang)部(bu)分(fen)分(fen)界(jie)明(ming)顯(xian)。後(hou)期(qi)病(bing)斑(ban)中(zhong)心(xin)顏(yan)色(se)轉(zhuan)淡(dan),並(bing)著(zhe)生(sheng)灰(hui)黑(hei)色(se)小(xiao)黴(mei)點(dian)。發(fa)病(bing)嚴(yan)重(zhong)時(shi),病(bing)斑(ban)連(lian)接(jie)成(cheng)片(pian),整(zheng)個(ge)葉(ye)片(pian)迅(xun)速(su)變(bian)黃(huang),並(bing)提(ti)前(qian)脫(tuo)落(luo)。
ziweihebanbingshiyouqianqucaikeweibaojunqinranyinqi,bingjunshiyijunsitihuofenshengbaoziqidexingshizaibingcantishangyuedong,ciniantongguofenshengbaozijinxingchuqinranhezaiqinran,bingjieqiliuhuofengyuchuanbomanyan。zaigaowenduoyu,youqishibaofengyupinfandenianfenhuojijieyibaofa;通常下層葉片比上層葉片易感染。
防治方法:
園藝防治 及早發現,及時清除病枝、病葉,並集中燒毀或深埋,以減少病菌來源。加強栽培管理、整形修剪,使植株通風透光。
藥劑防治 發病初期,可噴灑50%多菌靈可濕性粉劑500倍液,或65%代森鋅可濕性粉劑1000倍液,或75%百菌清可濕性粉劑800倍液。
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