樱桃叶斑病菌生物学特性及室内药剂筛选

Biological Characteristics and Fungicides of Cherry Leaf Spot Disease Pathogen

【目的】明确青海省樱桃叶斑病菌杨柳炭疽菌Colletotrichum salicis的生物学特性,并筛选出高效的杀菌剂。【方法】采用十字交叉法及孢子计数法研究了病原菌的生物学特性,并用生长速率法测定病原菌对26种杀菌剂的敏感性。【结果】该病原菌的最适培养基为PDA;菌落生长和产孢的最适碳源分别为肌醇和葡萄糖,菌落生长和产孢的最适氮源分别为牛肉膏和蛋白胨。该菌在5~40℃条件下均能生长,且最适温度为25℃,致死条件为58℃水浴处理10 min;在pH值为4~12内均可生长和产孢,最适pH值为7;在12 h/12 h光暗交替下,菌落生长快且产孢多。供试杀菌剂中化学与生物杀菌剂抑菌效果最好的分别是10%苯醚甲环唑WG和0.3%丁子香酚SL,其EC50值分别为0.6、1.15 mg·L^(-1);20%乙蒜素EC、80%代森锰锌WP和500 g·L^(-1)异菌脲SC的抑菌效果较差,EC50值高达301.44、679.36、1012.52 mg·L^(-1)。【结论】明确了樱桃叶斑病病原菌生长和产孢的最适培养条件和营养物质,并筛选出抑菌效果较好的杀菌剂。

【Objective】Biological characteristics of Colletotrichum salicis,the pathogen that causes the leaf spot disease on cherry plants in Qinghai Province,were studied and effective fungicides evaluated for the control.【Methods】C.salicis were examined by the cross and spore counting methods.Its sensitivity to 26 fungicides was determined in the laboratory according to the growth inhibition on culture media.【Results】PDA medium was found to be optimal for the C.salicis mycelial growth and sporulation.Inositol and glucose were the optimal carbon sources for sporulation,while beef extract the nitrogen for colony growth and peptone for spore production.The pathogen could grow between 5℃and 40℃but most rapidly at 25℃and died at 58℃in 10 min;between pH 4 and 12 but optimally at pH 7;and well under a photoperiod cycle of 12 h light/12 h dark.Among the tested antifungal agents,10%phentermine methiconazole aqueous dispersion or 0.3%eugenol dissolvable solution had the greatest inhibition with EC50 of 0.6 mg·L^(-1)and 1.151 mg·L^(-1),respectively,whereas 20%allicin oil emulsion,80%manganese zinc wettable powder,and 500 g·L^(-1)isobaric urea suspension the least efficacies with EC50 up to 301.44mg·L^(-1),679.36 mg·L^(-1),and 1012.52 mg·L^(-1),respectively.【Conclusion】The conditions and nutrients for optimal C.salicis culture were determined and the effective fungicides were identified.