Adult time-mortality response and changes in reproductive attributes in <i>Callosobruchus maculatus</i> (Fab.) following UV irradiation

Abstract

Using 254nm UV radiations of exposure periods from 2 to 16 min against adults. Time mortality response of the cowpea weevil, Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae), adults and alterations in vital reproductive attributes as fecundity, immature duration, adult emergence and adult longevity of the beetles from parental through F 1 generation have been estimated. Time mortality response of the adults of the cowpea weevil Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae), and alternations in vital reproductive attributes is fecundity, immature duration, adult emergence and longevity from parental through F 1 generation using 254nm UV radiations of response periods from 2-16min have been estimated. Results show that an exposure time to kill 50% of the adults is around 20 min (LT 50 = 19.99min), and irradiation significantly reduced egg-laying (P<0.001), lengthened immature durations (i.e. larval and pupal developmental periods; P<0.05), decreased adult emergences as well as longevity in both sexes (P<0.001) in the parental generation. The effects of the UV-rays on F 1 progenies, however, were less pronounced than that expressed in the parental generation, but the immature duration was significantly increased (P<0.01) but the longevity in both sexes was significantly reduced (P<0.001). Relevance of this study in relation to prospective phytosanitary treatments of the stored pulses with UV-rays has been discussed.