美丽崖豆藤炭疽病病原鉴定及防治药剂的室内毒力测定

Pathogen identification of anthracnose disease on Millettia speciosa and indoor determination of fungicide toxicity

【目的】明确引起美丽崖豆藤炭疽病的病原菌种类并筛选其防治药剂。【方法】采用组织分离法对病原菌进行分离、纯化后,利用柯赫氏法则验证其致病性,依据菌株的形态学特征和多基因序列分析确定病原菌种类;采用菌丝生长速率法测定病原菌对生产上常用于炭疽病防治的4种杀菌剂的敏感性。【结果】分离得到的6株菌中有2株菌可侵染美丽崖豆藤叶片引起褐色病斑;结合形态学鉴定和多基因序列分析,确定引起美丽崖豆藤炭疽病的病原菌为暹罗刺盘孢Colletotrichum siamense。该病菌对苯醚甲环唑、咪鲜胺、吡唑醚菌酯和甲基硫菌灵的敏感性均高,抑制中浓度(EC50)均小于0.1 mg/L,其中,以咪鲜胺的防效最佳,EC50为0.015 mg/L。【结论】美丽崖豆藤炭疽病的病原菌为暹罗刺盘孢,苯醚甲环唑、咪鲜胺、吡唑醚菌酯和甲基硫菌灵可作为防治美丽崖豆藤炭疽病的首选药剂。

【Objective】To determine the pathogen causing anthracnose disease on Millettia speciosa and screen effective fungicides.【Method】Tissue isolation method was used to isolate the pathogen.The pathogenicity was tested according to Koch’s rule after purification.The pathogen was identified based on morphological characteristics and multi-locus sequence analysis.Furthermore,the sensitivity of this pathogen against four common fungicides was measured according to the mycelial growth rate.【Result】Two out of six obtained isolates could infect M.speciosa leaf and caused brown spot.Combining morphological characteristics and multi-locus sequences analysis,the pathogen caused anthracnose disease on M.speciosa was identified as Colletotrichum siamense.This pathogen was highly sensitive to difenoconazole,prochloraz,pyraclostrobin and thiophanate-methyl with EC50 values below 0.1 mg/L,and prochloraz showed the highest efficacy with EC50 of 0.015 mg/L.【Conclusion】The pathogen causing anthracnose disease on M.speciosa is C.siamense,and difenoconazole,prochloraz,pyraclostrobin and thiophanate-methyl can be applied to control anthracnose disease in the field.