广东省辣椒疫霉菌对嘧菌酯的敏感性

从广东省各地采集了54个辣椒疫霉菌株,分别测定了菌丝生长和游动孢子囊形成对嘧菌酯的敏感性。结果表明,嘧菌酯对辣椒疫霉的菌丝生长具有很强的抑制作用,EC₅₀范围为0.1428～1.9509μg/mL,平均为0.9649μg/mL;对游动孢子囊形成的抑制作用更强,EC₅₀范围为0.0010～0.0844μg/mL平均为0.0239μg/mL。正态分析表明,辣椒疫病菌54个菌株菌丝生长对嘧菌酯的敏感性符合正态分布,而孢子萌发则在高浓度区具有拖尾现象,表明自然界中已存在个别具有一定耐药性的辣椒疫霉种群。

Sensitivity of Phytophthora capsici to azoxystrobin in Guangdong

Fifty-four isolates of the pathogen Phytophthora capsici of capsicum blight were collected from several capsicum-planting areas in Guangdong Province.Sensitivity experiments showed that mycelial growth of the pathogen was affected by azoxystrobin,with a mean EC₅₀as 0.964 9 μg/mL,ranging from 0.142 8 μg/mL to 1.950 9 μg/mL,and sporangial formation was affected by the fungicide to a greater extent,with a mean EC₅₀as 0.023 9 μg/mL,ranging from 0.001 0 μg/mL to 0.084 4 μg/mL.Normal distribution analysis showed that the sensitivity of these isolates to azoxystrobin was fitted well with a normal distribution function,but that of sporangial formation was not.The results suggested that,under natural conditions in Guangdong,there were some strains of capsicum blight pathogen that had resistance to the fungicide to some extent.