Insecticidal activity of Dennettia tripetaia Baker f. and Piper guineense Schum. and Thonn. against Dermestes
maculatus Degeer (Coleoptera: Dermestidae) and Necrobia rufipes Degeer (Coleoptera: Cleridae) on dried fish .
OKONKWO, E. U. and W. I. OKOYE
ABSTRACT: Various stages of Dermestes maculatus Degeer and Necrobia rujipes Degeer were placed in Kilner jars containing dried catfish Clarias sp. treated separately with 0.25, 0.5, 0.75 and 1.0g of Dennettia tripetala Baker f. and Piper guineense Schum. and Thonn. seed powders’ / 25g of fish. D. tripetala and P. guineense seed powders significantly (P<0.05) inhibited oviposition and achieved 100% adult mortality of the test insects in 7 days. In treated fish, larvae did not develop beyond second instar and 100% of larvae
died by day 30 with D. tripetala powder being more insecticidally active. Minimal frass was produced in fish treated with both plant powders at 0.25g powder 125g of fish. In experiments under simulated storage conditions, essential oil extracts of D. tripetala and
P. guineense treated at 0.1, 0.2 and 0.3ml / 25g of fish significantly (P < 0;05) inhibited oviposition and achieved 100% adult mortality of both D. maculatus and N. rufipes in 7days, and there-was no progeny development by day 30. In treated fish, all the larvae
died after 7 days, as compared to\fish treated with 0.1 and 0.2ml groundnut oil / 25g and the untreated control. The aesthetic attractiveness of the fish was high. There are prospects for use of D. tripetala and P. guineense powder and essential oil extracts in the protection of dried fish in storage in Nigeria.