辣椒疫霉病菌对内吸性杀菌剂抗药性的研究

从江西省采集分离的辣椒疫病菌（ＰｈｙｔｏｐｈｔｈｏｒａｃａｐｓｉｃｉＬｅｏｎｉａｎ）１５３个菌株对甲霜灵抗药性测定结果表明：野生已有５５．６０％的菌株存在抗药性，其中中、高抗菌株占２７．５０％；甲霜灵与恶唑烷酮、甲呋酰胺之间存在交互抗性，与霜霉威之间没有交互抗性；甲霜灵对敏感菌株菌丝生长、游动孢子囊的形成和游动孢子的释放均有明显的抑制作用，其ＥＣ５０分别为０．２７７６ｍｇ／ｋｇ、０．２６６３ｍｇ／ｋｇ、２．２９５ｍｇ／ｋｇ，而霜霉威浓度达５００ｍｇ／ｋｇ时，对菌株菌丝生长、游动孢子囊的形成和游动孢子的释放均没有明显的抑制作用，但在活体寄主上对病菌有较好的防效。

Study on Resistance of Phytophthora capsici to Systemic Fungicides

The resistance of 153 Phytophthora capsici isolates fror Jiangxi to metalaxyl was studied. The results showed that resistant isolates took up 55.6% in the total, including 27.5% HR or MR. The cross-resistance existed among metalaxyl, oxadixyl and ofurance p. capsici but it didn't do between metalaxyl and propamocarb.Metalaxyl can inhibited evidently the hyphal growth, sporangin production and zoospore release, with EC 50 of 0.277 6, 0.266 3 and 2.295 mg/kg respectively, and 500 mg/kg propamocarb couldn't do that, but the later could control P. Capsici on the host well.