Pharmacokinetic Mechanisms Associated with Synergism by DEF of Cypermethrin Toxicity in Larval and Adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae)
Authors: Usmani, K. Amin; Knowles, Charles O.
Source: Journal of Economic Entomology, Volume 94, Number 4, August 2001 , pp. 874-883(10)
Publisher: Entomological Society of America
Abstract: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.
Document Type: Research Article
Publication date: 2001-08-01
- Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
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