海南橡胶树炭疽病调查及喀斯特炭疽病菌的鉴定

Investigation of Colletotrichum sp.and Identification of C.karstii of Rubber Trees in Hainan

天然橡胶是四大工业原料中唯一的可再生资源,由炭疽病菌侵染引起的橡胶树炭疽病是当前我国橡胶生产上最为严重的两大叶部病害之一。本研究通过调查海南省主栽橡胶树品种(系)及监测炭疽病发生流行情况,调查发现PR107和RRIM600种植面积最大,分别占51.06%(102000 hm^(2))和43.39%(86700 hm^(2));在对橡胶树炭疽病的随机踏查和固定监测中发现,该病在实生苗、嫁接苗、增殖苗、各主栽品种幼龄树和成龄胶园中全年均可发生,3—4月为盛发期;海南省橡胶树种植面积大,且品种(系)单一,因此炭疽病在适宜发病条件下易暴发流行。通过形态观察、致病性测定和多基因系统发育分析发现,分离自琼中县阳江农场苗圃橡胶树叶片上的菌株HCkHNQZ1736为喀斯特炭疽菌(Colletotrichum karstii),这是首次在海南省橡胶树上发现该类病菌。致病力评价发现其对PR107、RRIM600、热研7-33-97和大丰95四个主推品种均有强致病力。杀菌剂敏感性测定结果表明,菌株HCkHNQZ1736和分离自云南保山的同种菌株MeCkYN1705对咪鲜胺锰盐差异不显著且不具抗药性,EC_(50)分别为0.0784μg/mL和0.0775μg/mL。HCkHNQZ1736对多菌灵表现出高抗药性,EC_(50)达1107.2654μg/mL,而MeCkYN1705的EC_(50)仅为0.0554μg/mL。

Rubber tree(Hevea brasiliensis)is the only renewable resource among the four major industrial raw materials.The rubber tree anthracnose which infected by the Colletotrichum sp.is one of the most serious foliar disease of rubber production in China.In this study,we investigated the main rubber tree varieties(strains)and monitoring the occurrence and prevalence of anthracnose in Hainan province.It was found that PR107 and RRIM600 had the largest planting area,accounting for 51.06%(102000 hm^(2))and 43.39%(86700 hm^(2))respectively.The anthracnose of mature rubber planta-tions and value-added nurseries in Yangjiang Farm was occurred all year round,with the peak period from March to April;Therefore,the rubber tree planted in Hainan province was large,and the variety(strain)was single,so it was easy to break out and spread when the anthracnose was suitable.HCkHNQZ1736 isolated from the leaves of the rubber nurs-ery of Yangjiang Farm in Qiongzhong County,was identified as a new strain of Colletotrichum karstii,which had highly pathogenic to four main varieties of rubber tree,PR107,RRIM600,Reyan 7-33-97 and Dafeng 95.Studied on the results of carbendazim and prochloraz-manganese sensitivity test of HCkHNQZ1736 and MeCkYN1705 showed that the two strains had no resistance to prochloraz-manganese,while the EC_(50)was 0.0784µg/mL and 0.0775µg/mL respec-tively.However,HCkHNQZ1736 showed high resistance to carbendazim,at this time,the EC_(50)was 1107.2654µg/mL,while MeCkYN1705 had only 0.0554µg/mL.