黄瓜霜霉病菌对氟吗啉的抗性风险研究初报

以黄瓜霜霉病菌为材料，通过室内抗性诱导以及大棚抗性诱导等方法，对其抗性情况进行研究。结果表明：经过室内连续15代的抗性诱导，黄瓜霜霉病菌对氟吗啉的抗性略有上升，抗性倍数从初始的1．8l倍上升到3．58倍。在大棚条件下，黄瓜霜霉病菌对氟吗啉的抗性并没有上升，抗性倍数均维持在1．03-1.69之间。另外，抗性菌株的竞争能力明显低于敏感菌株。在不加药的条件下，抗性菌株的频率逐渐下降，从初始的50％下降到0．79％；在间隔用药的情况下，抗性菌株的频率从初始的50％逐渐上升到62.82％，上升速率也非常缓慢。这些结果初步表明，黄瓜霜霉病对氟吗啉的抗性风险可能较低。

Preliminary Studies on the Risk of Flumorph Resistance Development in Pseudoperonospora cubensis

Flumorph resistance induction studies were conducted with Pseudoperonospora cubensis in the laboratory and greenhouse. Flumorph resistance in P. cubensis increased slightly following 15 generations of resistance induction in the laboratory, with resistance rising from 1.81 to 3.58 times that of a control. Resistance in the greenhouse did not increase, however, with induced strains showing resistance enhancement by only 1.03 to 1.69 times. In addition, mycelia competitive ability of these induced resistant strains was significantly lower than that of the susceptible strains. In the absence of flumorph, the frequency of resistant mycelia gradually decreased from an initial 50% to 0.79%. Under conditions of intermittent flumorph exposure, frequency of resistant mycelia gradually increased, from an initial 50% to 62.8%, with a very low rate of increase. These preliminary results indicate that risk of flumorph resistance development in Pseudoperonospora cubensis is relatively low.