Resistance Level and Enzyme Activity of Spodoptera litura F. to Chlorpyrifos and Their Sensitivity to the Oil Formulation of Azadirachta indica Juss. and Cymbopogon nardus (L.) Rendl.

This study aimed to obtain resistance information of S. litura from Karangpawitan and Lembang districts (West Java, Indonesia) against chlorpyrifos insecticides (200 g/l) their sensitivity oil mixture A . indica C nardus (1:1) using feeding topical assay. The activity acetylcholinesterase, esterase, glutathione s-transferase larvae in both populations were tested determine role insect resistance. Results showed that population had a higher level compared Karangpawitan. the two relatively similar ratio (RR) value less than 1 botanical insecticide. These indicated resistant could be controlled by this botanicals Enzyme test at concentration 0.26% inhibit acetylcholinesterase 98.66% while those Lembang, it was only 35.31%. Specific esterase 13.37 units/mg 119.65 units/mg. specific Glutathione S-Transferase (GST) 1140.82 793.73 high three enzymes responsible for chlorpyrifos.