The Monitoring of Sensitivity of Acetylcholinesterase to Organophosphates inPlutella xylostella(L.) and Apanteles plutellae Kurd

It showed that the resistance to organophosphates(OPs) was associated with the insensitivity of acetylcholinesterase(AChE) in P. xylostella and .plutellae Kurd. by determining the kinetic parameters, K m, V max and the bimolecular rate constant K i.There was lower sensitivity of AChE to isofenphos methyl and methamidophos applied from Sep.to Apr.,but higher sensitivity of AChE from Jun.to Aug. in field monitoring. Meanwhile, the tendency of the change of AChE sensitivity in A.plutellae was correlative with that of P.xylostella but the sensitivity of AChE in A.plutellae was higher than that of P.xylostella .It could be concluded that the AChE sensitivity in P.xylostella and A. plutellae was associated with the insecticide pressure in environment.