Penetration, metabolism, and excretion of radiocarbon were observed after topical treatment of Helicoverpa zea (Boddie), Spodoptera frugiperda (J. E. Smith), and Agrotis ipsilon (Hufnagle) larvae and adults with cypermethrin-14C. These pharmacokinetic events usually were higher with trans-cypermethrin-14C than with cis-cypermethrin-14C. They also were generally higher with H. zea and S. frugiperda than with A. ipsilon, and they were higher in larvae than in adults. No marked sex differences in the degradation of trans-cypermethrin were apparent. Pretreatment of H. zea, S. frugiperda, and A. ipsilon larvae and adults with S,S,S-tri-n-butyl phosphorotrithioate (DEF) 30 min before application of cypermethrin resulted in a perturbation of trans-cypermethrin pharmacokinetics manifested primarily by a lower rate of pyrethroid metabolism as compared with that in the absence of DEF. Appreciably higher internal levels of the toxic parent pyrethroid were often observed in the presence of DEF than in the absence of DEF in most cases. Suppression of cypermethrin penetration and elimination also was usually detected. Inhibition by DEF of the enzymatic degradation of cypermethrin may account for the synergy observed between these two compounds.
How to translate text using browser tools
1 August 2001
Pharmacokinetic Mechanisms Associated with Synergism by DEF of Cypermethrin Toxicity in Larval and Adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae)
K. Amin Usmani,
Charles O. Knowles
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Journal of Economic Entomology
Vol. 94 • No. 4
August 2001
Vol. 94 • No. 4
August 2001
cypermethrin
Noctuidae
pharmacokinetics
S,S,S-tri-n-butyl phosphorotrithioate
synergism