番石榴枝枯病菌生物学特性及防治药剂筛选OA

[Objective]This study aims to clarify the biological characteristics of Neopestalotiopsis egyptiaca,the causal agent of guava twig blight,and screen effective fungicides to provide a theoretical basis for disease control.[Method]The effects of different culture conditions on fungal growth and conidial germination were determined through single-factor experiments.The inhibitory effects of six common chemical fungicides were evaluated using the mycelial growth rate method.[Result]The optimal mycelial growth was observed at 25℃,pH 5.0,and under 24 h light exposure.In contrast,sporulation was significantly enhanced at 20℃,pH 10.0,and under 12 h light conditions.The optimal conidial germination occurred at 25℃and pH 7.0.Furthermore,both mycelia and conidia exhibited certain salt tolerance.Among the six tested fungicides,thiophanate-methyl and pyraclostrobin showed the strongest inhibitory effects,with half maxmal effective concentration(EC50)of 0.698 6 and 1.405 4 μg·mL-1,respectively.Kasugamycin and mancozeb also demonstrated inhibitory activity,with EC50 of 244.477 1 and 365.990 5 μg·mL-1,respectively.[Conclusion]N.egyptiaca exhibits strong adaptability,thriving across a wide range of temperatures and pH levels.In vitro toxicity tests indicate that thiophanate-methyl and pyraclostrobin are the most effective fungicides and should be prioritized for field control.