当归新病害——炭疽病病原鉴定及发病规律研究

Pathogen identification and occurrence regularity of a novel disease——Angelica anthracnose

2012年至2013年在甘肃省各当归主产区发现的一种疑似当归炭疽病的病害,该病害主要危害植株茎秆。发病初期先在植株外部茎秆上出现浅褐色病斑,随后病斑逐渐扩大,形成深褐色长条形病斑,叶片变黄枯死,茎秆从外向内逐渐干枯死亡,后期在病斑上出现黑色小颗粒(分生孢子盘),最后整株枯死。通过病菌形态学鉴定、ITS基因序列分析以及致病性测定,已确定该病害是由束状炭疽菌危害引起的当归炭疽病。本研究系首次报道。经过室内盆栽接种试验表明,针刺、灌根和喷雾接种均能发病,以针刺发病最重,其次为灌根处理,喷雾接种最轻,表明病菌通过伤口、根部以及地上部分均可侵入;此病一般在6月中、下旬开始发生,8月下旬到9月上旬达到发病高峰,田间发病率、病情指数与气温和相对湿度存在极显著的正相关,即温度高、湿度大有利于病害发生,且湿度的影响大于温度影响。本研究为当归炭疽病的防治提供了依据。

A suspected anthracnose disease on Angelicastems was found in the main producing areas in Gansu province in 2012 and 2013.The major damage of this disease is to the plant stem.In the initial stages of the disease,many light brown spots appear on stems,and then expand to dark brown rectangular lesions,leaf chlorosis and wilting.Stems gradually dry up from outside to inside,abundant black acervuli appear on the spots,and then the plant dies.Through pathogenicity testing,morphology and ITS sequence analysis we determined that the pathogen of Angelicaanthrax is Colletotrichum dematium.As far as we know,this study is the first report for this disease.An inoculation test using potted plants indoors shows that puncturing,root-irrigation and spraying with conidial suspension all can cause disease.Puncturing caused the most severe symptoms.Spraying with suspension induced the lightest symptoms.C.dematium can infect Angelica through wounds,roots and aerial parts.This disease first appears in mid or late June,and incidence peaks in late August or early September.Field temperature and relative humidity are significantly positively correlated with disease incidence and severity,suggesting that high temperature and high humidity promote progress of the infection.The impact of humidity on disease development is greater than temperature.This study provides a basis for developing prevention and control methods for Angelicaanthrax.