Contact activities of Piper guineense(Schum and Thonn) and Eugenia aromaticum( L). (Merril and Perryl) extracts in the control of Dermestes maculatus larvae infesting stored fish (Clarias gariepinus) was investigated under laboratory condition (28 Â±3oC and 65Â± 5% R,H.). The extracts were tested by application of 2.0ÂµL each to ten third instars larvae using micro pipette at a concentration of 6.00, 10.00 and 20.00% of each of plants extracts (methanol, n-hexane and ethyl acetate). Mortality was recorded at 1, 2, 3 and 7days of post treatments. The observed mortality was dose and exposure - dependents. All the extracts significantly enhance larval mortality (P>0.05) when compared to control. The n- hexane and ethyl-acetate extracts of Piper guineense at 20% concentration induced the highest mortality of 86.66%, lowest mortality of 56.66% was observed on methanol fraction treated larvae after 7days of post treatments. The n-haxane of E. aromaticum extracts recorded highest mortality (80.0%), followed by ethyl-acetate (76.66%) and methanolic (7.00%) fractions treated larvae at 20% concentration after 7days of post -treatments. The results showed strong insecticidal activity in control of larvae of hide beetles infesting dried fish.
Keywords: Plant extracts, Piper guineense, Eugenia aromaticum ,Dermestes maculatus