小菜蛾对九种杀虫剂的抗药性

Resistance of Plutella xylostella to nine insecticides in several field populations in China

采用叶片药膜法测定了9种杀虫剂对海南、山东、广东、湖北武汉和襄樊等5个地区小菜蛾Plutella xylostella（L．）田间种群的毒力，和室内相对敏感品系比较。结果显示，5个地区的小菜蛾种群都对氯氰菊酯产生了10倍以上的抗性，广东和山东种群达到30倍以上的抗性。对阿维菌素的抗性山东小菜蛾种群达到135倍，广东种群达到30倍，其他地区均在10倍以下。但是，作用机制与阿维菌素类似的药剂，氟虫腈的抗性5个地区均在5倍或5倍以下。对昆虫生长调节剂定虫隆和氟虫脲的抗性除广东种群分别在10倍和20倍以上外，其他地区均在5倍以下。广东种群对多杀菌素的抗性为7．8倍，其他地区的种群没有产生抗性，多杀菌素和杀虫双均为作用于乙酰胆碱受体的药剂，但是作用的位点不同。杀虫双对5个种群的LC90值均是比较大的（〉800mg／L），尽管没有明显的抗性，不适宜用于小菜蛾田间防治。对呼吸链电子转移抑制剂溴虫腈的抗性均在10倍以下。对辛硫磷的抗性在2～5倍。

Five field populations of Plutella xylostella （L.） were collected from Hainan, Shandong, Guangdong, Wuhan, and Xiangfan areas of ttubei, respectively. Bioassay of the toxicity of nine insecticides to the five populations of the insect was carried out by dipping leaves method. The results showed that five field populations of Diamondback moth produced more than 10 fold resistance to cypermethrin compared with relatively susceptible lab colony. Among them, Guangdong and Shandong field populations produced over 30 fold resistance to eypermethrin. Resistance of field populations, which are from Shandong and Guangdong, to abameetin was over 135 fold and 30 fold, respectively whereas other field populations were relatively sensitive to abameetin with less than 10 fold resistance compared with that of relatively susceptible lab colony. Although fipronil has similar action mechanism to abameetin, resistance ratio of fipronil was 5 fold or lower. Field populations in Guangdong produced 10 fold and 20 fold resistance to chlorfluazuron and flufenoxuron, respectively, whereas other field populations lower than 5 fold. Field population from Guangdong produced 7.8 fold reslstanee to abameetin whereas other four field populations were sensitive. Although AChR is the same target site of spinosad and dimehypo, they have different action sites. Toxicity of dimehypo to five field populations of diamondback moth was very low with LCs0 more than 80t3 mg/L although diamondback moth didn＇ t produce any resistance to dimehypo. Resistance ratio of five field populations of diamondback moth was lower than 10 fold to ehloffenapyr, a kind of inhibitor to respiration chain and electron transfer. Resistance ratio of five field populations of diamondback moth to phoxim was between two fold and five fold.