取食吡蚜酮及吡虫啉亚致死浓度处理棉蚜对十一星瓢虫捕食功能的影响

Effects of Aphis gossypii treated with sublethal concentration of pymetrozine and imidacloprid on the predatory function of Coccinella undecimpunctata

本文研究了吡蚜酮及吡虫啉亚致死浓度处理棉蚜对十一星瓢虫捕食功能的影响,结果表明:取食吡蚜酮和吡虫啉亚致死浓度处理棉蚜后,对十一星瓢虫各龄期幼虫和成虫的捕食功能均产生不利影响,且吡虫啉的影响程度较吡蚜酮更大。饲喂吡虫啉LC25处理的棉蚜后,十一星瓢虫日捕食量较对照总体降低,其中2~4龄幼虫日捕食量下降最为显著,十一星瓢虫的各龄幼虫和成虫的瞬时攻击率分别下降4.64%、12.35%、9.03%、22.92%和2.02%;处理单头棉蚜的时间分别延长0.0064 d、0.0031 d、0.0005 d、0.0005 d和0.0004 d;日最大捕食量(1/Th)分别下降1.80头、4.62头、6.54头、7.01头和7.14头;4龄幼虫的控害效能(a/Th)在各龄期幼虫中受影响最为显著,与对照相比下降32.4292;寻找效应随猎物密度增加而呈现不同程度的下降。饲喂吡蚜酮LC25处理棉蚜后,十一星瓢虫各龄期幼虫和成虫捕食功能的各项指标总体较对照下降不明显,说明吡蚜酮LC25在棉蚜体内的残留量对十一星瓢虫捕食功能造成的影响较小。以上研究结果可为利用天敌与农药协同防控棉蚜提供参考依据。

This study explored the effects ofAphis gossypii treated with sublethal concentrations of pymetrozine and imidacloprid on the predatory function of Coccinella undecimpunctata,the results showed that after feeding onA.gossypii treated with sublethal con-centration of pymetrozine and imidacloprid,the predation function of all instar larvae and adults of C.undecimpunctata were adversely affected,and the impact of imidacloprid was greater than that of pymetrozine.After feeding theA.gossypii treated with LC25 of imida-cloprid,the daily predation of C.undecimpunctata was decreased on totals,among them,the decrease of the daily predation of 2nd to 4th instar larvae were the most significant,the instantaneous attack rate of each instar larvae and adults of C.undecimpunctata were de-creased by 4.64%,12.35%,9.03%,22.92%and 2.02%;the handling time of singleA.gossypii were prolonged by 0.0064 d,0.0031 d,0.0005 d,0.0005 d and 0.0004 d;the daily maximum predation amounts(1/Th)were decreased by 1.80 head,4.62 head,6.54 head,7.01 head and 7.14 head;the control efficiency(a/Th)of 4th instar larva was the most significantly affect in each instar larvae,it was reduced by 32.4292;with the increase of density,the searching efficiency presented a various degree of decrease compared with the control group.After feeding theA.gossypii treated with pymetrozine LC25,the various indexes of the predatory function response of C.undec-impunctata had no significant decrease,it explained that the pymetrozine LC25 residue inA.gossypii had little effect on predatory func-tion ofC.undecimpunctata.These results can provide a reference for the coordinated control ofA.gossypii by enemies and pesticides.