High level methoprene resistance in the mosquito Ochlerotatus nigromaculis (Ludlow) in central California.
In the summer of 1998, failures of methoprene field applications to control the mosquito Ochlerotatus nigromaculis (Ludlow) were noticed in several pastures in the outskirts of Fresno, California, USA. Effective control with methoprene had been achieved for over 20 years prior to this discovery. Susceptibility tests indicated that the Fresno Oc nigromaculis populations had developed several thousand-fold higher LC50 and LC90 tolerance levels to methoprene compared with methoprene-naïve populations. The synergists piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate and 3-octylthio-1,1,1-trifluoro-2-propanone had little synergistic effect, suggesting that the mechanism of methoprene tolerance was not mediated by P450 monooxygenase or carboxylesterase enzyme degradation. As part of initiating a resistance management strategy, partial reversion back to methoprene susceptibility was achieved in a resistant population after six consecutive applications of Bacillus thuringiensis israelensis Goldberg & Marga coupled with two oil and two pyrethrum + PBO applications.
Department of Entomology, University of California, Davis, Kearney Agricultural Center, Mosquito Control Research Laboratory, Parlier, CA 93648, USA. cornel@uckac.edu
Anthony J
AJ
Cornel
Matthew A
MA
Stanich
Rory D
RD
McAbee
F Steve
FS
Mulligan
D000096:Acetone / Q000031:analogs & derivatives / Q000494:pharmacology; D000383:Agriculture; D000818:Animals; D001413:Bacillus thuringiensis / Q000502:physiology; D002140:California; D009033:Culicidae / Q000187:drug effects* / Q000382:microbiology; D004305:Dose-Response Relationship, Drug; D007305:Insecticide Resistance; D008726:Methoprene / Q000494:pharmacology*; D063086:Organothiophosphates / Q000494:pharmacology; D010574:Pesticide Synergists / Q000494:pharmacology; D010882:Piperonyl Butoxide / Q000494:pharmacology
D063086:Organothiophosphates; D010574:Pesticide Synergists; D000096:Acetone; C006863:butyl phosphorotrithioate; C055697:3-octylthio-1,1,1-trifluoro-2-propanone; D008726:Methoprene; D010882:Piperonyl Butoxide