【摘要】 通过对在中国新发现的梨梢枯病病原菌（Aureobasidium pullulans var. pullulans）在不同温度、pH、碳源、氮源和光照等培养条件和孢子致死温度的测定,明确病原菌的生长规律和死亡条件,并采用生长速率法对该病原菌进行9种杀菌剂的毒力筛选。结果表明:梨梢枯病病原菌菌丝生长的适宜温度为15～25 ℃,最适温度为20 ℃,温度高于35 ℃时,菌丝生长缓慢;菌丝生长最佳培养基为PDA培养基,产孢最佳培养基为OA培养基;甘露醇和酵母粉分别为菌丝生长和产孢的最佳碳源和氮源;菌丝可在pH 4～10条件下生长,pH 5为生长最适pH;光照对菌丝生长有促进作用,并且有利于病原菌产孢,在光暗交替的培养条件下,菌落会形成明显的轮纹。病原菌分生孢子的致死温度为48.9 ℃。该病原菌对75%肟菌·戊唑醇水分散粒剂的敏感性较高,其EC₅₀ <0.01 mg·L^-1;对70%甲基硫菌灵可湿性粉剂、50%多菌灵可湿性粉剂、43%氟菌·肟菌酯悬浮剂和325 g·L^-1苯甲·嘧菌酯悬浮剂的敏感性次之,其0.01 mg·L^-1 <EC₅₀ <1 mg·L^-1。更多还原

【Abstract】 To investigate the biological characteristics and fungicides sensitivity of the newly purified strains of Aureobasidium pullulans var. pullulans,which cause serious spot blight of pears. The effects of different carbon and nitrogen sources,pH values,temperatures and light conditions on the mycelial growth rate and spore productions were evaluated. The indoor toxicity of nine fungicides on the mycelium of A. pullulans var. pullulans was determined by the growth rate method of mycelium. The regression equation of virulence was established by the logarithm of concentration and probability value,the correlation coefficient（r）and estimate concentration of 50%(EC₅₀)btained. The results showed that the suitable temperature for mycelium growth and spore production of the pathogen was ranged from 15 ℃ to 25 ℃,and 20 ℃ was the optimum. When the temperature exceeds 35 ℃,the growth rate of mycelium becomes very slow. PDA was the optimal media for mycelium growth,while OA was the optimal media for spore production. Mannitol and Yeast extract were optimal for mycelium growth and spore production.A. pullulans var. pullulans could grow on the medium of pH 4–10. The optimum pH for mycelium growth and spore production was 5. Light promoted spore production and mycelium growth. The obvious ringlets observed on the colony with the cultural condition of alternating dark and light. The lethal temperature of conidia was 48.9 ℃. The sensitivity of A. pullulans var. pullulans to nine fungicides was evaluated by the growth rate method of mycelium. The results showed that the pathogen was more sensitive to 75% Trifloxystrobin·Tebutazol WDG,EC₅₀ < 0.01 mg·L^-1,followed by 70%Thiophanate-methyl WP,50% Carbrndazim WP,43% Fluopyram·Trifloxystrobin SC and 325 g·L^-1 Difenoconazole·Azoxystrobin SC,0.01 mg·L^-1 < EC₅₀ < 1 mg·L^-1.更多还原