【目的】系统地研究罗汉松(Podocarpus macrophyllus)叶枯病病原物——罗汉松拟盘多毛孢(Pestalotiopsis podocarpi)的生物学特性并进行室内抑制药剂筛选,为该病害有效防控提供参考。【方法】在不同营养条件、温度、pH、光照处理下通过玻片萌发法测定罗汉松拟盘多毛孢孢子的萌发率,以分析其生物学特性。采用含毒介质生长速率法和玻片萌发法对75%(质量分数,下同)百菌清、50%多菌灵、80%代森锰锌、70%甲基托布津等4种药剂进行室内筛选,分别测定了不同药剂在不同浓度下对罗汉松拟盘多毛孢菌丝生长和孢子萌发的抑制作用。通过拟合毒力回归方程计算有效浓度(EC₅₀),筛选得到有效药剂。【结果】寄主植物叶煎汁对病菌孢子萌发具有促进作用,最适浓度(体积分数)为10%;病菌孢子在15~35 ℃均能萌发,最适温度为25 ℃;在pH 6~9时萌发率可达50%以上,以pH为7时萌发率最高;病菌孢子对光照不敏感,光暗交替处理孢子萌发率略高于其他处理。多菌灵对罗汉松拟盘多毛孢菌丝生长抑制效果最好,其有效浓度(EC₅₀)为0.048 9 mg/L;甲基托布津效果次之,EC₅₀为0.850 5 mg/L;而代森锰锌和百菌清的效果较差。代森锰锌对病菌孢子萌发的抑制效果最好,EC₅₀为0.257 3 mg/L。甲基托布津、百菌清和多菌灵的抑制效果依次降低。【结论】适宜病原罗汉松拟盘多毛孢孢子萌发的罗汉松煎汁浓度(体积分数)为10%,最适生长温度和pH分别为25 ℃和7。可选用多菌灵和代森锰锌作为防治罗汉松叶枯病的潜在药剂,但其林间防效还需进一步研究。

【Objective】In order to effectively prevent and control the disease, this study aims to systematically investigate the biological characteristics of the pathogen causing Podocarpus macrophyllus leaf blight disease and screens effective fungicides.【Method】The germination rate of spores was measured under different nutritional conditions, temperatures, pH levels, and light treatments using the glass slide germination method to study the biological characteristics of Pestalotiopsis podocarpi. The four fungicides, including 75% (mass fraction) chlorothalonil, 50% (mass fraction) carbendazol, 80% (mass fraction) mancozeb, and 70% (mass fraction) thiophanate-methyl, were evaluated in vitro for their efficacy in restraining hyphal growth and conidia germination. The toxicity regression equations were fitted to calculate the EC₅₀, and effective fungicides were screened.【Result】The host plant decoction could promote spore germination, with the optimal concentration being 10%. The spores could germinate between 15-35 ℃, with the optimal temperature at 25 ℃. The germination rate could exceed 50% at pH 6-9, peaking at pH 7. The spores were insensitive to light, with alternating light-dark treatment resulting in slightly higher germination rates than other treatments. The most effective one against hyphal growth is carbendazol with the EC₅₀ of 0.048 9 mg/L, followed by thiophanate-methyl with the EC₅₀ of 0.850 5 mg/L. Mancozeb and chlorothalonil are less effective against hyphal growth. Mancozeb demonstrates the strongest inhibitory effect on conidia germination with the EC₅₀ of 0.257 3 mg/L, followed in decreasing order of effectiveness by thiophanate-methyl, chlorothalonil, carbendazol.【Conclusion】The optimal concentration of P. macrophyllus decoction for spore germination of P. podocarpi is 10%. The optimal growth temperature and pH are 25 ℃ and 7, respectively. Carbendazol and mancozeb can be used as potential fungicides for controlling podocarpus (P. macrophyllus) leaf blight disease, while their field control efficacy requires further research.