灭菌唑与氰烯菌酯复配对水稻恶苗病菌的抑制活性

采用菌丝生长速率法，测定了灭菌唑对水稻恶苗病菌的毒力，测得灭菌唑对10株水稻恶苗病菌的EC₅₀值范围为0.0664~0.7661 μg/mL。采用有效成分质量浓度分别为60、120和240 μg/mL的25 g/L灭菌唑种子处理悬浮剂处理水稻种子后，对水稻发芽率、株高、鲜重均无影响。表明灭菌唑对水稻恶苗病菌具有较好的抑制活性，且对水稻安全，可用于水稻恶苗病的化学防控。氰烯菌酯对10株水稻恶苗病菌的EC₅₀值范围为0.0076~0.2629 μg/mL。将氰烯菌酯和灭菌唑分别按质量比4 : 1、3 : 1、2 : 1、1 : 1、1 : 2、1 : 3和1 : 4复配，测定了复配药剂对水稻恶苗病菌的联合毒力，所得增效系数在0.5~1.5之间，均为相加作用。研究表明，将氰烯菌酯与灭菌唑复配后施用，不仅能显著降低单剂的使用剂量，且能降低氰烯菌酯对病原菌群体的选择压力，延缓抗药性的发生和发展速度，保障病害防效和水稻生产安全。

Antifungal activity of the compound of triticonazole and phenamacril against Fusarium fujikuroi

In this study, the mycelial growth rate method was used to determine the antifungal activity of triticonazole against Fusarium fujikuroi, and the EC₅₀ values of triticonazole against 10 strains of F. fujikuroi ranged from 0.0664 μg/mL to 0.7661 μg/mL. After seed treatment with 60, 120, and 240 μg/mL active concentrations of 25 g/L triticonazole suspension concentrate, the germination rate, plant height, and fresh weight of rice were not affected. The results indicated that triticonazole not only has good antifungal activity against F. fujikuroi, but also has good security for rice, and can be used to control rice bakanae disease. The EC₅₀ values of phenamacril against 10 strains of F. fujikuroi ranged from 0.0076 to 0.2629 μg/mL. The joint toxicities of phenamacril and triticonazole at the ratios of 4 : 1, 3 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 3, and 1 : 4 against F. fujikuroi were determined. The result showed the synergistic ratio ranged from 0.5 to 1.5, indicating that the combinations of phenamacril and triticonazole exhibited an additive effect on the inhibition of F. fujikuroi mycelial growth. This study indicated the combinations of phenamacril and triticonazole not only decrease the use dosage of a single component significantly but also reduce the selective pressure of F. fujikuroi populations to phenamacril and delay the resistance development, ensuring the control efficacy of rice bakanae disease and safe production of rice.