青海省樱桃叶斑病菌生物学特性及室内药剂毒力测定

Biological characteristics of pathogen causing leaf spot disease of cherry in Qinghai province and toxicity test of different fungicides in laboratory

为明确青海省樱桃叶斑病菌链格孢Alternaria alternata的生物学特性及筛选出对其防效最佳的药剂,本研究采用菌丝生长速率法和孢子计数法研究了不同培养条件对该病原菌菌丝生长和产孢量的影响,并用菌丝生长抑制率法对9种杀菌剂进行室内毒力测定。结果表明,菌丝生长和产孢的最适培养基分别为马铃薯蔗糖琼脂(PSA)培养基和马铃薯葡萄糖琼脂(PDA)培养基,最适温度为25℃,最适氮源为蛋白胨,最适碳源分别为肌醇和乳糖,最适pH分别为6~8和6~7,24 h持续黑暗处理更有利于菌丝生长和产孢。9种化学药剂对病原菌均有不同程度的抑制作用,其中250 g/L嘧菌酯悬浮剂抑菌效果最好,EC50为1.258 mg/L。该研究结果可为青海省樱桃叶斑病的防治提供理论依据。

The aim of this study is to confirm the biological characteristics of Alternaria alternata causing leaf spot disease of cherry in Qinghai province and to screen out the best fungicides.Influence of different culture conditions on mycelium growth and sporulation of pathogen was investigated using the mycelial growth rate method and spore counting method.The toxicity of nine fungicides to the pathogen was determined by mycelial growth inhibition method in laboratory.The results showed that the optimal medium for mycelium growth and sporulation was PSA medium and PDA medium,respectively.The optimal temperature was 25℃,the optimal nitrogen source was peptone,the optimal carbon source was inositol and lactose,and the optimal pH value was 6-8 and 6-7,respectively.24 h dark treatment was more favorable for mycelium growth and sporulation.Nine kinds of fungicides had different inhibition activity on the pathogen.Among them,azoxystrobin 250 g/L SC has the best antibacterial effect,with the EC50 value of 1.258 mg/L.The results provide a theoretical basis for the control of cherry leaf spot in Qinghai province.