药剂对稻曲病菌的毒力测定及复配研究

为筛选防治稻曲病的有效单剂和复配组合,采用菌丝生长速率法,测定烯唑醇、腈菌唑、丙环唑、咪鲜胺、苯菌灵、多菌灵、戊唑醇、井冈霉素、松脂酸铜9种杀菌剂及互相复配后对稻曲病菌的毒力,并比较了不同复配组合的协同作用.结果表明:稻曲病菌对烯唑醇最敏感,EC5o为0.145 μg/mL；井冈霉素对稻曲病菌的毒力作用最弱,EC50为13.6 μg/mL.从252种不同比例复配的药剂中,筛选出12种增效配方,其中烯唑醇和咪鲜胺复配(1∶10),协同系数高达3.70,增效作用最大；烯唑醇和咪鲜胺(1∶10)对稻曲病菌的毒力作用最强,EC5o为0.06μg/mL,其次是烯唑醇和咪鲜胺(1∶20)与烯唑醇和腈菌唑(10∶1),EC50分别为0.10μ/mL和0.11μg/mL.田间试验结果也表明:烯唑醇与咪鲜胺(1∶10)复配,对稻曲病的平均防效为79.2％,高于其他常用药剂.

Toxicity test of fungicides to Ustilaginoidea virens and mixed formulation

In order to select effective single-dose and compound fungicides for the control of rice false smut,the toxicity of diniconazole,myclobutanil,propiconazole,prochloraz,benomyl,carbendazim,tebuconazole,jinggangmycin,copper abietate and mixtures of them with different proportions were tested by the method of hyphal growth rate.The results showed that Ustilaginoidea virens was most sensitive to diniconazole,with an EC50 of 0.145 μg/mL;the toxicity of jinggangmycin was the lowest,with an EC50 of 13.6 μg/mL.Twelve formula with synergistic effects were selected from 252 pharmaceutical mixed doses with different proportions.The synergistic effect of the mixture of diniconazole and prochloraz at the proportion of 1∶10 was the best,with a concordance coefficient of 3.70.The EC50 of the mixture of diniconazole and prochloraz at the proportion of 1∶10,the mixture of diniconazole and prochloraz at the proportion of 1∶20 and the mixture of diniconazole and myclobutanilyl at the proportion of 10∶1 were 0.06 μg/mL,0.10 μg/mL and 0.11 μg/mL,respectively.The results of field experiments also indicated that the control efficiency of the mixture of diniconazole and prochloraz at the proportion of 1∶10 on rice false smut was 79.2%,better than other common fungicides.