广西不同地区小菜蛾田间种群对3种新型杀虫剂的抗性测定

目的]测定广西6个蔬菜产区的小菜蛾田间种群幼虫对氯虫苯甲酰胺、氟虫双酰胺和氰氟虫腙等3种新型杀虫剂的敏感性,为3种杀虫剂的合理使用及各种群对3种药剂的抗性监测提供基础数据.方法]采用浸叶法分别测定小菜蛾敏感品系和6个小菜蛾田间种群幼虫对氯虫苯甲酰胺、氟虫双酰胺、氰氟虫腙的敏感性,比较田间种群和敏感品系的LC50,计算小菜蛾田间种群的抗性倍数.结果]小菜蛾荔浦种群对氯虫苯甲酰胺最敏感,其LC50为0.000735 mg/L,抗性倍数为1.32倍,田东种群的敏感性最低,其LC50为0.004230 mg/L,抗性倍数达7.61倍;对于氟虫双酰胺,柳江种群的敏感性相对较低,其LC50为0.366 mg/L,抗性倍数为2.27倍,南宁安吉种群最敏感,其LC50为0.168 mg/L,抗性倍数为1.04倍;对于氰氟虫腙,柳江种群的敏感性相对较低,其LC50为4.692 mg/L,抗性倍数为2.96倍,荔浦种群最敏感,其LC50为1.622mg/L,抗性倍数为1.02倍.结论]小菜蛾田东种群对氯虫苯甲酰胺的抗性倍数为7.61倍,已达低水平抗性,应给予高度重视.其余地区的小菜蛾种群对3种杀虫剂的抗性倍数均低于5倍,仍处于敏感期,应加强不同药剂的轮换使用,以延缓小菜蛾抗性的形成与发展.

Resistance of Plutella xylostella (L.) to three new insecticides in field of different areas in Guangxi

【Objective】The susceptibility of larval field population of Plutella xylostella in six vegetable areas in Guangxi against chlorantraniliprole，flubendiamide and metaflumizone were evaluated to provide a theoretical basis for application of pesticide in Plutella xylostella and their resistance monitoring to these pesticides. 【Method】Comparative analysis on the LC50 value of the three pesticides between susceptible strains and field populations of Plutella xylostella， which employed the leaf dipping method （IRAC Method No. 7） to measure the toxicity of chlorantraniliprole， flubendiamide and metaflumizone against the larva of strain and the six field populations of Plutella xylostella， respectively， was used to determine the relevant resistance ratio. 【Result】The sensitivity of the field population in Tiandong County to chlorantraniliprole was the lowest， its LC50 value was 0.00423 mg/L， and its resistance ratio was 7.6 fold， while that in Lipu County was the highest， its LC50 value was 0.00735 mg/L， and its resistance ratio was 1.3 fold. The sensitivity of the field population in Liujiang County to flubendiamide was the lowest， its LC50 value was 0.366 mg/L， and its resistance ratio was 2.27 fold， while that in Anji aera was the highest， its LC50 value was 0.168 mg/L， and its resistance ratio was 1.04 fold. The sensitivity of the field population in Liujiang County to metaflumizone was the lowest， its LC50 value was 4.692 mg/L， and its resistance ratio was 2.96 fold， while that in Lipu County was the highest， its LC50 value was 1.622 mg/L， and its resistance ratio was 1.02 fold. 【Conclusion】In Tiandong County the field population had the resistance ratio of 7.61 fold， which meant low resistance， therefore adequate attention should be given. The resistance ratio to three pesticides of Plutella xylostella was less than 5 fold compared with the susceptible strain， except Tiandong population. Plutella xylostella of six field populations was still pretty sensitive to the three new insecticides. Consequently， these insecticides must be used in rotation to delay the resistant forming and growth.