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期 刊 ：植物保护学报 2010年

关键词：烯酰吗啉；嘧菌酯；辣椒疫霉；生物活性；

Keywords:dimethomorph, azoxystrobin, Phytophthora capsici, efficacy,

摘 要 ：为了分析烯酰吗啉与嘧菌酯对辣椒疫霉病原菌不同发育阶段的敏感性,分别采用离体和活体试验方法比较了供试药剂对病原菌的生物活性。结果表明,烯酰吗啉对辣椒疫霉菌菌丝生长、孢子囊产生以及游动孢子释放具有强烈的抑制作用,EC₅₀分别为0.68、0.21和4.92μg/mL,其活性分别是嘧菌酯的34.7、30.4和4.6倍。烯酰吗啉与嘧菌酯在浓度为12.5μg/mL时对菌丝体细胞膜的电导率无影响,但当烯酰吗啉和嘧菌酯的浓度分别为25μg/mL和50μg/mL时其电导率值明显上升。采用液相氧电极法,测定了三种典型抑制剂与供试药剂对菌丝体呼吸代谢的影响,结果显示,嘧菌酯作用于三羧酸循环(TCA)途径,而烯酰吗啉对三羧酸循环(TCA)途径和磷酸戊糖(HMP)途径有一定的影响。室内盆栽试验结果表明:在相同浓度下,烯酰吗啉与嘧菌酯对辣椒疫病均具有较好的保护效果,两者无显著差异;在辣椒植株接菌后24h采用800μg/mL的药液喷雾处理时,烯酰吗啉对辣椒疫病的防治效果为66%,优于嘧菌酯。

Abstract:The efficacies of dimethomorph and azoxystrobin against Phytophthora capsici were evaluated in this paper. The results in vitro indicated dimethomorph inhibited different stages in the life cycle of Phytophthora capsici including mycelial growth, sporangium production, zoospore release with the EC₅₀ values of 0.68, 0.21 and 4.92μg/mL respectively. The EC₅₀ values of dimethomorph are 34.7, 30.4 and 4.6 times those value of azoxystrobin respectively. To examine the effects of the two fungicides on the permeability of the cell membrane, the effects of the two fungicides on electrolyte leakage of mycelia cell suspension were studied. The conductivity of mycelia suspension treated with dimethomorph and azoxystrobin were both increased at 25μg/mL and 50μg/mL respectively. The changes of conductivity caused by the two fungicides were both subtle at 12.5μg/mL. Mycelial respiration rate test results showed that azoxystrobin had inhibition the approaches of tricarboxylic acid cycle (TCA) and the dimethomorph had an effect on the approaches of TCA and hexosemonophosphate (HMP). Bioassay in vivo showed that dimethomorph and azoxystrobin had similar protection effect against P.capsici with the same concentration, while dimethomorph had a better curative effect against P.capsici than azoxystrobin.

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