Bio-efficacy of Clerodendrum capitatum (Willd) Schumachet. Thonn. (Lamiales: Verbenaceae) against Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae) larvae infestation on smoked catfish Claria gariepinus (Burchell, 1822) (Siluriformes: Clariidae)

Abstract

Studies were conducted under ambient condition to assess the efficacy of Clerodendrum capitatum (Willd) Schumachet. Thonn. (Lamiales: Verbenaceae) against larvae infestation and adult emergence of Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae) on smoked dried catfish Claria gariepinus (Burchell, 1822) (Siluriformes: Clariidae). The leaf powder was admixed at 2.5 g, 3.0 g, 4.0 g and 5.0 g/15 g to disinfected smoke-dried catfish Clarias gariepinus separately in a 125 mL plastic container. Ten newly emerged (0-72 h) larvae of D. maculatus were introduced into each of the plastic containers. Efficacy of Clerodendrum capitatum was assessed based on percentage larval mortality, adult emergence reduction and weight loss. Results showed that the plant powder cause significantly (p < 0.05) larval mortality compared to the untreated fish at 24 h, 48 h and 72 h post infestation. Percentage reduction of adult emergence was not significant (p > 0.05) in treated fish samples compared to untreated sample. While fish sample protected with powder of Clerodendrum capitatum, exhibit significant (p < 0.05) low weight loss as against weight loss observed in untreated fish. The efficacy of Clerodendrum capitatum is inversely proportional to increase in dosage rate. This study clearly demonstrated the larvicidal potential of Clerodendrum capitatum powder in offering effective protection against infestation and damage by D. maculatus and recommended for utilization in integrated post-harvest management strategies of smoke-dried fish.