氟铃脲对水稻纹枯病菌的毒力和作用机制

Toxicity and mechanism of hexaflumuron on Rhizoctonia solani AG-1 IA

从现有成熟的昆虫生长抑制剂中寻找和挖掘具有抗真菌活性的药剂,不仅可以扩大该药剂的应用范围,还可以大大减少新药开发及其注册的费用和时间。室内毒力测定和田间药效试验结果表明,杀虫剂氟铃脲对水稻纹枯病菌具有很强的抑制作用,而且在水稻植株体上对水稻纹枯病菌的作用明显大于离体条件下的毒力,前者的EC_(50)是后者的4．1倍。氟铃脲处理水稻后对植株体内抗性相关酶的影响表明,50μg/mL氟铃脲喷洒水稻后,植株体内的β-1,3葡聚糖酶的活性在第7天达到最高,总几丁质酶活性在喷药后第14天增加明显。由此表明,该药剂在水稻植株体上具有诱导产生抗病反应的作用。50μg/mL氟铃脲田间防治水稻纹枯病的效果达到88．6%,为其替代井冈霉素提供了依据。

To try to seek and discover new antifungal activity from now available mature insect inhibitors, not only being able to expand their application ranges, but also being able to reduce the invest and time of developing new pesticides. We found the mycelial growth of Rhizoctonia solani AG-1 IA was suppressed by insecticide hexaflumuron. By comparing the virulence of this chemical to R. solani AG-1 IA on cultural medium PDA （ in vitro） and on rice plant （ in vivo）, the toxicity of the chemical to this fungus was 4.1 times higher in vivo than in vitro. Stronger activities of 13-1, 3-glucanase and total chitinase in the rice sheath were stimulated treated with 50μg/mL hexaflumuron after 7 d and 14 d, respectively. These results suggested that not only there is the direct toxicity of the pesticide against the pathogen but also defense reactions were triggered in rice plant after spraying it. Hexaflumuron will be a potential chemical which re- placed Jinggangmycin because its effect on rice sheath blight in rice field was 88.6%.