Leaf mold, which is cause by Cladosporium paeoniae, is one of the most serious diseases on peony, causing reduced growth, flower discolouration and peony seed oil reduction. In order to screen fungicides for the control of peony leaf mold, this paper investigated the inhibitory activity of four fungicides, pyraclostrobin, phenamacril, flutolanil and boscalid, on the growth and development of Cladosporium paeoniae using the coating plate method, and further determined the field control efficacy of the fungicides against leaf mold using fungicide sprays. The results showed that pyraclostrobin had strong inhibitory activity against all developmental stages of the fungus, with EC₅₀ of 0.0045, 0.0013, 0.0184 and 0.0072 μg/mL for conidial germination, germ tube elongation, mycelial growth and conidial production, respectively. Phenamacril strongly inhibited germ tube elongation and conidial production, with EC₅₀ of 0.3358 and 0.1368 μg/mL respectively, and also inhibited conidial germination, but had little effect on mycelial growth. Both flutolanil and boscalid showed weak inhibition of conidial germination and germ tube growth with EC₅₀ above 25 μg/mL. Boscalid had strong inhibitory effects on mycelial growth and conidia production, with EC₅₀ less than 2.2 μg/mL, but flutolanil had almost no inhibitory effects on mycelial growth and could even promote sporulation of the pathogen. Although all four fungicides inhibited elongation of germ tubes, none of them had significant teratogenic effects on germ tubes and conidia production. Compared with the control group without any spraying, all four fungicides significantly decreased the disease index in the field after application, and all achieved more than 60% control efficacy on the disease; with the increase of the dilution of the fungicide, the control efficacy was reduced. Pyraclostrobin and phenamacril are recommended for use as protective fungicides before the appearance of leaf mold, while after disease occurrence, pyraclostrobin and boscalid are recommended.

由牡丹枝孢引起的叶霉病是牡丹最严重的病害之一，可引起生长减慢、花朵变色和牡丹籽油减少。为筛选防治牡丹叶霉病的杀菌剂，本文采用包衣板法考察了唑菌胺酯、非那麦利、氟唑菌胺和啶酰菌胺4种杀菌剂对牡丹枝孢菌生长发育的抑制活性，并进一步确定了该领域使用杀菌剂喷雾剂控制杀菌剂对叶霉病的控制效果。结果表明，唑菌胺酯对真菌的各个发育阶段都有很强的抑制活性，EC ₅₀0.0045、0.0013、0.0184 和 0.0072 μg/mL 分别用于分生孢子萌发、胚芽管伸长、菌丝体生长和分生孢子生产。Phenamacril强烈抑制胚管伸长和分生孢子产生，EC ₅₀分别为0.3358和0.1368 μg/mL，对分生孢子萌发也有抑制作用，但对菌丝生长影响不大。氟唑尼和啶酰菌胺均显示出对分生孢子萌发和胚管生长的弱抑制作用，EC ₅₀高于25 μg/mL。啶酰菌胺对菌丝生长和分生孢子产生有很强的抑制作用，EC ₅₀小于2.2 μg/mL，但对菌丝体生长几乎没有抑制作用，甚至可以促进病原菌的孢子形成。尽管所有四种杀菌剂都抑制了胚管的伸长，但它们都没有对胚管和分生孢子产生显着的致畸作用。与未施药的对照组相比，四种杀菌剂施用后田间病害指数均显着降低，均达到60%以上的病害防治效果；随着杀菌剂稀释度的增加，防治效果降低。推荐在叶霉出现前使用吡唑醚菌酯和非那美利作为保护性杀菌剂，而在病害发生后推荐使用吡唑醚菌酯和啶酰菌胺。