Fenoxycarb - a potent inhibitor of metamorphosis and reproduction in Rice Moth, Corcyra cephalonica (Stainton)
Rizwana Begum and Ayesha Qamar
Six different concentrations viz. 0.025%, 0.05%, 0.1%, 0.25%, 0.5% and 1.0% of fenoxycarb were topically applied at 2µl dose to the last instar larvae of rice moth, Corcyra cephalonica. There was a concentration-based and time-dependent response with respect to various life cycle parameters as quantified in the present work. The larvae treated with 0.5% and 1.0% fenoxycarb did not reach the adult stage as the mortality occurred owing to direct knockdown, incomplete moulting and unsuccessful metamorphosis. At concentration 0.05% and 0.025% fenoxycarb resulted in retardation of metamorphosis and developmental rate of the surviving C. cephalonica larva/pupae which, during the course of developmental path, showed morphological abnormalities. The females that emerged from treated stock exhibited malformed reproductive system along with reduced fecundity and hatchability. Furthermore, when the normal eggs were contact exposed to fenoxycarb (0.025% to 1.0%) the hatching was prevented in 37.2%-57.2% eggs; thus indicating the gonadotropic action of the current juvenoid. Therefore, fenoxycarb appears to be a promising agent for the control of C. cephalonica with the pronounced effects on the development and reproduction.