百合新病原菌假短孢弯孢生物学特性及其对杀菌剂的敏感性

The biological characteristics of Curvularia pseudobrachyspora,a new causal agent of lily leaf spot,and its sensitivity to fungicides

假短孢弯孢Curvularia pseudobrachyspora是我国新记录种,首次在龙牙百合贮藏期腐烂鳞茎上发现,并能引起龙牙百合叶斑病。为明确其生物学特性及其对药剂的敏感性,研究了不同碳源、氮源、pH、光照、温度等处理对病原菌菌丝生长的影响,并采用菌丝生长速率法测定该病原菌对9种杀菌剂的敏感性。研究表明,最适合菌丝生长的碳源为麦芽糖和木糖,氮源为牛肉浸膏,pH为7.0~8.0,最适温度为30℃,致死温度为52℃,黑暗条件有利于菌丝生长,病原菌可以侵染马铃薯、甘薯、荠菜,不能侵染蒜、葱。在9种参试杀菌剂中,1%申嗪霉素SC对该病原菌的毒力最高,相应的抑制中浓度EC 50为0.012 mg/L;68%精甲霜·锰锌WG的毒力最低,EC 50为15.820 mg/L。

Curvularia pseudobrachyspora is a new record in China.It was found for the first time on the rotten bulbs of Longya lily during storage and could cause the leaf spot of Lilium brownii var.viridulum.The biological responses of the pathogen to different carbon sources,nitrogen sources,pH and light treatments were also studied.The results showed that the most suitable carbon sources were xylose and maltose;the most suitable nitrogen source was beef extract;the optimum temperature for the mycelium growth was 30℃,and the mycelium lethal temperature was 52℃;the optimum pH for the mycelium growth was 7.0-8.0,and the suitable light condition for the mycelium growth was 24 h dark.The sensitivity of the pathogen to nine fungicides was tested,and the results showed that the inhibitory effects of six fungicides on the mycelium growth of the pathogen were significant.The fungicide shenqinmycin 1%SC had the strongest inhibitory effect among the fungicides tested,with an EC 50 value of 0.012 mg/L.The fungicide metalaxyl-M·mancozeb 68%WG had the minimum inhibitory effect,with an EC 50 value of 15.820 mg/L.