title: Identification of factors responsible for insecticide resistance in Helicoverpa armigera.
abstract: Moth larvae (Helicoverpa armigera Hübner) collected from field crops were tested for resistance to cypermethrin, fenvalerate, endosulfan, monocrotophos and quinolphos. Larvae were treated with a dose of the pesticide that would kill 99% of the susceptible insects. The percent survival of the resistant strains was determined. Highest seasonal average percentage survival was recorded by fenvalerate (65.0%) followed by cypermethrin (62.4%). Acetylcholinesterase of resistant larvae was less sensitive to monocrotophos and methyl paraoxon. Resistant larvae showed higher activities of esterases, phosphatases and methyl paraoxon hydrolase compared with susceptible larvae. The presence of high activity of esterases was attributed to appearance of extra bands of esterases in native PAGE. The presence of P-glycoprotein expression was detected in resistant larvae using P-gp antibodies; this was not detected in the susceptible larvae. Our results indicate that the high level of resistance detected in the field pests could be because of a combined effect of decreased sensitivity to AChE, higher levels of esterases, phosphatases and the expression of P-gp.
authors.affiliation: Department of Biochemistry, Gulbarga University, 585 106, Karnataka, India.
authors.forename: R
authors.initials: R
authors.lastname: Srinivas
authors.forename: S S
authors.initials: SS
authors.lastname: Udikeri
authors.forename: S K
authors.initials: SK
authors.lastname: Jayalakshmi
authors.forename: K
authors.initials: K
authors.lastname: Sreeramulu
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D001681:Biological Assay; D004591:Electrophoresis, Polyacrylamide Gel; D004726:Endosulfan / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D004950:Esterases / Q000378:metabolism; D006867:Hydrolases / Q000378:metabolism; D007305:Insecticide Resistance; D007306:Insecticides / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D007814:Larva; D008999:Monocrotophos / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D009036:Moths / Q000187:drug effects* / Q000201:enzymology*; D009570:Nitriles; D009946:Organothiophosphorus Compounds / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D010261:Paraoxon / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D011722:Pyrethrins / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D012621:Seasons
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000906:Antibodies; D007306:Insecticides; D009570:Nitriles; D009946:Organothiophosphorus Compounds; D011722:Pyrethrins; C017160:cypermethrin; C009145:quinalphos; D008999:Monocrotophos; D006867:Hydrolases; D004950:Esterases; D010744:Phosphoric Monoester Hydrolases; D004726:Endosulfan; D010261:Paraoxon; C008480:methylparaoxon; C017690:fenvalerate