Contact activities of Piper guineense (Schum and Thonn) and Eugenia aromaticum (L). (Merril and Perryl) extracts against larvae of hide beetles, Dermestes maculatus (Degger) (Coleoptera: Dermestidae)

Abstract

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 ) were investigated under laboratory condition (28 ±3°C and 65±5% RH). The extracts were tested by application of 2.0 µL 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 7 days of post treatments. The observed mortality was dose and exposure-dependents. All the extracts significantly enhance larval mortality (P>0.05) when compared with control. The n-hexane and ethyl-acetate extracts of P. 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 the highest mortality (80.0%), followed by ethyl-acetate (76.66%) and methanolic (7.00%) fractions treated larvae at 20% concentration after 7 days of post-treatments. The results showed strong insecticidal activity in control of larvae of hide beetles infesting dried fish.