苯醚甲环唑与戊唑醇混配对水稻稻曲病菌联合作用的测定

为明确苯醚甲环唑与戊唑醇不同比例混配对水稻稻曲病菌联合作用的类型,采用病菌菌丝生长抑制率和菌丝生长速率法测定了苯醚甲环唑、戊唑醇及其5种配比对水稻稻曲病菌的毒力作用。结果表明,苯醚甲环唑与戊唑醇对水稻稻曲病菌的EC50分别为1.568、21.487 mg/L,苯醚甲环唑对水稻稻曲病菌的室内生物活性明显优于戊唑醇。在苯醚甲环唑与戊唑醇的5个不同配比中,4:5配比的EC50最小,为1.858 mg/L。1:8、2:7、3:6、4:5混配组合的SR均大于1.5,表明上述4种混配组合对水稻稻曲病菌均表现为增效作用;(2~4):(7~5)配比的SR均大于2.0,增效作用最强。苯醚甲环唑、戊唑醇对水稻稻曲病菌均有较高的室内生物活性,二者按(2~4):(7~5)的比例混配对水稻稻曲病菌有增效作用。建议用药浓度为117~375 mg/L。

Determination of Combined Effect of Difenoconazole and Tebuconazole on Mixed Rice False Smut

Different proportion of difenoconazole and tebuconazole mixed together can affect ustilaginoidea virens. In order to clarify different types of this combined effect, the inhibitory rate of mycelium growth of the pathogen and mycelium growth rate method are used to determine virulence to ustilaginoidea virens from difenoconazole, tebuconazole and their 5 matching ratios. The results indicated that EC₅₀ of ustilaginoidea virens was 1.568 and 21.487 mg/L, respectively, when affected by difenoconazole and tebuconazole, and indoor bioactive of ustilaginoidea virens influenced by difenoconazole was more than that influenced by tebuconazole. In the 5 different matching ratios of difenoconazole and tebuconazole, ratio 4:5 had the least EC₅₀, which was 1.858 mg/L. Ratio 1:8, 2:7, 3:6 and 4:5 had SR which were all above 1.5 and this illustrated these 4 matching combinations all had a synergistic effect towards ustilaginoidea virens. In addition, ratio (2-4): (7-5) produced SR greater than 2.0 and had the strongest synergistic effect. Difenoconazole and tebuconazole both had higher indoor bioactivity to ustilaginoidea virens, and the two with matching ratio of (2-4): (7-5) had the best synergistic effect towards ustilaginoidea virens. The suggested drug concentration was 117-375 mg/L.