Title: Toxicology and metabolism of isomers of flumethrin in larvae of pyrethroid-susceptible and resistant strains of the cattle tickBoophilus microplus (Acari: Ixodidae)
Abstract: Some marked differences were found between the behaviour of flumethrin isomers and a companion pyrethroidtrans-cypermethrin, on susceptible and resistant strains ofB. microplus. Deposition of flumethrin on dipped larvae was approximately three times lower than that oftrans-cypermethrin. The metabolism (detoxication) of flumethrin was also approximately three times lower than that oftrans-cypermethrin. Coumaphos, which strongly synergized the effect oftrans-cypermethrin, was without effect on flumethrin. This was in accord with the effect of coumaphos on metabolism, which was not reduced as much in flumethrin-treated larvae as intrans-cypermethrin-treated larvae. This suggested that an enzyme other than a carboxylesterase was involved in the metabolism of flumethrin. In an earlier study, resistance to permethrin and cypermethrin in larvae of the Malchi strain greater than that exhibited by larvae of the DDT-R strain, (previously characterized pyrethroid-resistant strains), was attributed to increased metabolism. This greater resistance in the Malchi strain also extends to flumethrin, but cannot be accounted for by the same mechanism. One of the flumethrin isomers (trans-Z II) was extraordinarily toxic to larvae, being some fifty times more toxic than the hitherto most-toxic pyrethroids,cis-cypermethrin and deltamethrin. This is suggested as a possible reason for the success of flumethrin in a pour-on formulation for the control of ticks. Virtually no knock-down effect was exhibited by flumethrin, as opposed to the strong knock-down effect previously shown to be a feature of the action of other pyrethroids.
Publication Year: 1989
Publication Date: 1989-02-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 18
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