滇西菜区小菜蛾发生规律及抗药性监测

掌握滇西菜区小菜蛾Plutella xylostella种群发生规律和抗药性水平，对提出区域性防控策略具有重要意义。2009-2015年，采用诱集法和浸叶法监测了滇西菜区小菜蛾种群发生动态及其对常用杀虫剂的抗药性。结果表明：滇西菜区小菜蛾全年发生，为害期有9个月，春夏季为害重，3-6月为发生高峰期，2009-2015年最高诱蛾量为290~905头/7 d，小菜蛾种群对化学杀虫剂均产生了不同水平的抗药性，其中对阿维菌素和高效氯氰菊酯的抗药性最高，达到高水平抗药性，对多杀菌素、茚虫威和溴虫腈维持在中等水平抗药性，2011年对氯虫苯甲酰胺产生了28倍的抗药性，后恢复敏感，3年后又出现抗药性的上升趋势。可见，3-6月是滇西菜区小菜蛾防控的重要时期，可选择Bt、多杀菌素、茚虫威和溴虫腈等药剂轮换使用，减少氯虫苯甲酰胺使用次数，建议停用阿维菌素和高效氯氰菊酯。

Occurrence and resistance monitoring of Plutella xylostella in Western Yunnan

Study of population of occurrence and resistance level of Plutella xylostella is important to put forward regional control strategies in Western Yunnan. From 2009 to 2015, we monitored the dynamic of population occurrence of adult P. xylostella and their resistance to common insecticide by sex pheromone attraction-inducing method and indoor leaf immersion method. The result showed that P. xylostella occurred throughout the year in western Yunnan, and the damage last 9 months. The damage was severer in spring and summer. And the peak period was from March to June. The maximum number of light tripping was 290~905/7 d in 2009 to 2015. The population had developed different degrees of resistance to several commonly used insecticides. The highest resistance was occurred on abamectin and beta-cypermethrin. Pleocidin, indoxacarb and chlorfenapyr were maintained at medium resistance level. The resistance to chlorantraniliprole was reached up to 28 times in 2011. Then restored the sensitive. And the resistance raised again after three years. March to June was an important period for prevent and control. Bt, pleocidin, indoxacarb and chlorfenapyr should be selected in rotation. Do not single using chlorantraniliprole to avoid high levels of resistance. And abamectin and beta-cypermethrin should be discontinued.