Role of Carboxyamidase in the in vivo metabolism of Chlorfluazuron in the Black Cutworm, Agrotis ipsilon (Hfn.) (Lepidoptera : Noctuidae)

Fahmy, Adel Ramzy

doi:10.21608/eajbsa.2008.15733

Role of Carboxyamidase in the in vivo metabolism of Chlorfluazuron in the Black Cutworm, Agrotis ipsilon (Hfn.) (Lepidoptera : Noctuidae)

Document Type : Original Article

Author

Adel Ramzy Fahmy

Entomology Department, Faculty of Science, Ain Shams University Cairo 11566, Egypt

10.21608/eajbsa.2008.15733

Abstract

Triphenyl phosphate (TPP), a carboxylesterase
inhibitor, has synergized chlorfluazuron in the resistant strain of the black
cutworm but not in the susceptible strain. In vivo metabolism of ¹⁴C
– chlorfluazuron revealed that the amount of radiolabeled major metabolites
(2,6 – difluorobenzoic acid and 2,6 – difluorobenzamide) recovered from
resistant larvae was four times higher
than susceptible larvae. Addition of TPP did not affect chlorfluazuron metabolism
pattern in the susceptible insects but it caused a significant reduction of the
amount of detected metabolites in the resistant insects. Cleavage of
chlorfluazuron molecule took place at one or both of the urea C-NH-C bonds which suggests the responsibility of
carboxyamidase enzyme for chlorfluazuron metabolism. In vitro assays
revealed that carboxyamidase activity was about four times higher in the
resistant larvae than the susceptible ones which supports the hypothesis of the
involvement of carboxyamidase in chlorfluazuron resistance in this insect pest.

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