牡丹黑斑(TPBS),主要由链格孢菌引起,是观赏牡丹常见的叶部病害,这对当年的花蕾和来年的开花质量构成了很大的威胁。然而,只有一种杀菌剂注册控制了这种疾病,苯醚甲环唑.为避免因长期使用苯醚甲环唑引起的病原菌耐药性问题,有必要筛选更多的化学杀菌剂用于TPBS的预防和控制。在论文中,氟他尼的生物活性,非那普利,吡唑酮酯,和菌丝生长上的云菌丝,分生孢子萌发,测定了苦参的胚管伸长和孢子形成量,和现场控制疗效进行评估,以评估预防和治疗活动。苯醚环唑,同时用作对照。结果表明,吡唑醇对分生孢子萌发的抑制作用最强,菌丝生长,胚芽管伸长和孢子形成量,平均EC50分别为0.0517、0.5343、0.0008和0.8068μg/mL。氟妥兰对沙棘四个发育阶段的抑制活性弱于其他三种杀菌剂。与氟妥兰相比,boscalid,其他琥珀酸脱氢酶抑制剂,对菌丝生长和孢子形成量有更大的抑制作用,平均EC50分别为3.8603和1.4760μg/mL。非那普利有中等抑制水平,对分生孢子萌发和胚管伸长有更强的抑制活性,平均EC50为31.5349和5.2597μg/mL。四种杀菌剂对孢子和胚芽管的形状均无显著影响。对照杀菌剂苯醚甲环唑对菌丝生长的抑制作用最强,平均EC50仅为0.3297μg/ml。然而,其对其他三个生长阶段的抑制活性不高。在现场试验中,即使在低浓度下,吡唑酮对TPBS也有很高的控制功效,达到最低62.6293%,高于苯醚甲环唑。其他3种杀菌剂在高浓度时具有较高的防治效果,但在低浓度时显著下降。考虑到剂量和控制效果,吡唑酮酯是控制TPBS的第一选择。吡唑雌胺酯是苯醚甲环唑在生产中预防和控制TPBS的首选替代杀菌剂。
Tree peony black spot (TPBS), mainly caused by Alternaria suffruticosae, is a common leaf disease on the ornamental peony, which poses a great threat to the flower buds in the current year and the flowering quality in the next year. However, there is only one fungicide registered for the control of this disease, difenoconazole. In order to avoid the severe problem of pathogen resistance caused by long-term use of difenoconazole, it is necessary to screen more chemical fungicides for the prevention and control of TPBS. In this study, the biological activities of flutolanil, phenamacril, pyraclostrobin, and boscalid on mycelial growth, conidial germination, germ tube elongation, and sporulation quantity of A. suffruticosae were determined, and the field control efficacy was tested to evaluate the preventive and therapeutic activities. Difenoconazole was used as a control simultaneously. The results showed that pyraclostrobin had the strongest inhibitory effects on the conidial germination, mycelium growth, germ tube elongation, and sporulation quantity, with the average EC50 values of 0.0517, 0.5343, 0.0008, and 0.8068 μg/ml, respectively. The inhibitory activity of flutolanil on the four developmental stages of A. suffruticosae was weaker than that of the other three fungicides. Compared with flutolanil, boscalid, the other succinate dehydrogenase inhibitor, had more strong inhibitory effects on the mycelial growth and sporulation quantity, with the average EC50 values of 3.8603 and 1.4760 μg/ml, respectively. Phenamacril had a moderate inhibitory level and had more inhibitory activity on conidial germination and germ tube elongation, with the average EC50 values of 31.5349 and 5.2597 μg/ml, respectively. All of the four fungicides had no significant effects on the shape of spores and germ tubes. The control fungicide difenoconazole had the strongest inhibitory activity on mycelial growth, and the average EC50 value was only 0.3297 μg/ml. However, its inhibitory activity on the other three growth stages was not high. In the field trials, pyraclostrobin had high control efficacy on TPBS even at low concentrations, reaching a minimum of 62.6293%, which was higher than that of difenoconazole. The other three fungicides had higher control efficacy at high concentrations but decreased significantly at low concentrations. Considering the dosage and control efficacy, pyraclostrobin was the first choice for the control of TPBS. Pyraclostrobin is the preferred alternative fungicide to difenoconazole for the prevention and control of TPBS in production.