Abstract: Leaf blight is one of the most serious leaf diseases on Chrysanthemum morifolium, a Chinese medical herb in Zhejiang Province. In this study, the mycelium growth rate method and spore germination method were used to screen the control agents of C. morifolium leaf blight. The protective and curative efficacy of fungicides including pyraclostrobin against leaf blight disease were determined. The sensitivity baseline of Phoma bellidis population (n = 113) to pyraclostrobin was built. The results indicated that fludioxonil, prochloraz, and pyraclostrobin exhibited the best inhibitory activity on the mycelium growth rate of P. bellidis among the 9 tested fungicides, with the EC₅₀ values of 0.04, 0.06 and 0.07 μg/mL, respectively. In contrast, only the two QoIs, pyraclostrobin and azoxystrobin, showed good inhibitory activity on spore germination, with EC₅₀ values of 0.18 and 2.21 μg/mL. Pyraclostrobin, pyraclostrobin + difenoconazole (V/V=1 : 1), and pyraclostrobin + fludioxonil (V/V=1 : 1) exhibited good protective efficacy against leaf blight disease. However, the curative efficacy of all treatments was weaker than their protective efficacy. The EC₅₀ values of pyraclostrobin for inhibiting mycelial growth of P. bellidis population(n=113) ranged from 0.01 to 0.49 μg/mL, and the average EC₅₀ value was (0.28 ± 0.11) μg/mL. The sensitivity frequency distribution conforms to normal distribution, and it can be used as the sensitivity baseline of P. bellidis to pyraclostrobin. These results provide the basis and guidance for the management of leaf blight on C. morifolium, effective and reasonable application of pyraclostrobin, and the monitoring of resistance development in the future.