寄主植物对小菜蛾田间种群抗药性衰退及其酯酶活性的影响

通过毒力测定和生化分析,研究小菜蛾[Plutella xylostella(L.)]田间种群对12种杀虫剂的抗性稳定性,探讨花椰菜(Brassica oleraceavar.botrytisDC)、芥兰(B.alboglabraBailey)、上海青[B.campestrisL.ssp.Chinensis(L.)M ak ino]、甘蓝(B.oleraceaKale)等4种不同寄主植物对抗药性衰退的影响,以及在此过程中小菜蛾幼虫乙酰胆碱酯酶和羧酸酯酶的活力变化.结果表明,在脱离选择压力的条件下,用花椰菜饲养4代后,小菜蛾对氯氰菊酯、杀虫双、灭多威、杀灭菊酯、毒死蜱、辛硫磷、甲胺磷抗性水平较快下降,抗性衰退比达1.65-3.68,而对阿维菌素、氟虫腈、虫螨腈、氟啶脲和刺糖菌素的敏感性变化相对较小,抗性衰退比为0.90-1.19.小菜蛾取食不同寄主植物4代后对甲胺磷敏感性变化显著,以取食上海青的小菜蛾种群最为敏感,其次为取食芥兰、甘蓝和花椰菜的种群,F1代与F5代的LC50比值分别为3.68、4.43、5.18、7.70.衰退过程中,不同种群乙酰胆碱酯酶和羧酸酯酶活力均有所下降,F5代各种群间乙酰胆碱酯酶比活力差异不显著,而羧酸酯酶比活力间则有显著差异,比活力大小顺序依次为花椰菜、芥蓝、甘监、上海青的小菜蛾种群,F1代与F5代活力比值分别为1.72、1.90、2.70、5.14;F1种群的米氏常数(Km)值明显高于F5种群,为F5种群的1.61-2.10倍,而F5代各种群变化不大,F1代种群的最大反应速率Vm ax与F5各种群相比没有明显差异.

Influence of host plants on the resistance recession and esterase activity of Plutella xylostella L. field population

Toxicity bioassay and biochemical analysis were conducted to find the resistance stability of Plutella xylostella L.field population to 12 kinds of insecticides,and the influence of 4 kinds of host plants Brassica oleracea var.botrytis DC,B.alboglabra Bailey,B.campestris L.ssp.Chinensis(L.) Makino,B.oleracea Kale,on the resistance recession of Plutella xylostella L.Fuzhou field population,and on the change of activity of larva acetylcholinesterase(AchE) and carboxylesterase(CarE) in the recession process.After being fed for 4 generations with B.oleracea,and being absent to insecticides selection,the resistance level to cypermethrin,bisultap,methomyl,fenvalerate,chlorpyrifos,phoxim and methamidophos declined apparently and the LC_(50) ratio of F_1 to F_5 ranged from 1.62 to 3.68.But the susceptibility to avermectin,fipronil,chlorfenapyr,chlorfluazuron and spinosad didn′t show apparent variation between F_1 and F_5 population,the ratio was between 0.90 and 1.19.The order of P.xylostella susceptibility to methamidophos was those reared for 4 generations respectively on B.campestris L.ssp.Chinensis,B.alboglabra,B.oleracea,B.oleracea var.botrytis,in which the LC_(50) ratio of F_1 to F_5 were 3.68,4.43,5.18,7.70,respectively.In the course of resistance recession,the activities of both AchE and CarE reduced.AchE activities of F_5 reared with different plants were not significantly different while CarE activities had significant difference.Insects CarE activities from the highest to lowest were those reared on B.oleracea var.botrytis,B.alboglabra,B.oleracea,B.campestris L.ssp.Chinensis and LC_(50) ratio of F_1 to F_5 were 1.72,1.90,2.70,5.14,respectively.K_m values of F_1 generation were higher than F_5(from 1.61 to 2.10 times) while there were no apparent variation among different populations of F_1.V_(max) values of F_1 population were not apparently different from F_5 populations.