柑橘轮斑病菌的生物学特性及有效防治药剂筛选.

【Objective】The paper aimed to clarify the biological characteristics of different strains of Pseudofabraea citricarpa from different districts, and screen effective control agents to provide data support for precise and efficient prevention and control of this diseases. 【Method】The growth rate method was used to determine the biological characteristics including the optimal growth temperature, pH value, culture medium, carbon source, nitrogen source of 3 strains of P. citricarpa from Shaanxi, Hubei and Chongqing, which were separately named WZSS1, CGDS2 and YLSDP80. The indoor toxicity of 24 fungicides for 3 strains of P. citricarpa was also measured. 【Result】Three strains of P. citricarpa all could grow at temperature ranging from 0 to 30 ℃, and with the fastest growth occurring between 15-20 ℃. When the temperature reached 35 ℃, the mycelium of 3 strains all could not grow. The mycelium of three strains could grow within the pH range of 4-11. Among them, the pH values most suitable for the growth of WZSS1, CGDS2, and YLSDP80 strains were 4, 5 and 6, respectively. When the pH value reached 12, all three strains could not grow. In the tested culture medium, all three strains had the largest colony diameter and loose colonies on Czapek’s medium. On the same culture medium, CGDS2 had the lowest colony diameter and growth rate, while WZSS1 had the highest. The optimal carbon sources for WZSS1, CGDS2 and YLSDP80 were sucrose, soluble starch and glucose, respectively. When the carbon source was fructose, YLSDP80 strain could grow normally, and the colony diameter was 20. 67 mm, while WZSS1 and CGDS2 strains could not. Except for ammonium carbonate, three strains could grow on other 14 nitrogen sources. Urea significantly inhibited the growth of WZSS1 and CGDS2, while ammonium sulfate inhibited the mycelial growth of YLSDP80. There were significant differences in the inhibitory effects of different pesticides on three strains of P. citricarpa. Among them, 10% feniconazole, 25% prochloraz, 43% tebuconazole all showed good inhibitory effects on three strains, with EC50 values below 0. 30 μg/mL. However, 50% carbendazim and 2% chloramphenicol for WZSS1 strain, 22. 5% imidacloprid for CGDS2 strain, 3% probiotics for YLSDP80 strain had poor inhibitory effects of the mycelial growth separately, with the highest EC50 value reaching 378. 584 μg/mL. 【Conclusion】The P. citricarpa strain is suitable for growth in a culture environment with a temperature of 15-20 ℃, pH value of 5, soluble starch and sucrose as carbon sources, and glutamine, proline and ammonium chloride as nitrogen sources. The inhibitory effects of 10% benzofenapyr, 25% prochlorpene and 43% tebuconazole on the mycelial growth of three strains are significant, making them potential agents for preventing and control citrus target spot disease. [ABSTRACT FROM AUTHOR]