Repellent effects of some plant oils on Dermestes maculatus larvae in Smoke-dried West African lungfish (Protopterus annectens)

Abstract

AbstractDermestes maculatus accounts for about 71.5% of dried fish infestation in most of the producing areas with a substantial loss in both dry weight and nutritional value. The study aimed to evaluate the repellent effect of oils extracted from Garlic (Allium sativum), Coconut (Cocos nucifera), Ginger (Zingiber officinale), Jatropha (Jatropha curcas), and Neema (Azadirachta indica) on Dermestes maculatus larvae in smoke-dried Protopterus annectens. The extracted oils from each plant were applied to the fish at varying concentrations of 0.001, 0.004, 0.016, 0.064, and 0.256 ml/g fish in triplicates. Late instar larvae of D. maculatus were introduced into Kilner jars containing fish treated with these oils and repellency was monitored for 24 hrs. Repellency was highest (87%) in A. sativum oil and lowest (59%) in A. indica oil at the highest concentration (0.256 ml/g of fish) within 24 hrs. of exposure. Furthermore, an increasing trend in repellency was observed with increasing concentrations of oils from all the plants used. The order of repellency performance was A. sativum > C. nucifera > Z. officinale > J. curcas > A. indica, starting with the highest to the lowest. Therefore, this study demonstrates the repellent properties of the oils in offering effective protection against infestation and damage by D. maculatus, suggesting that the oils can be utilized in post-harvest preservation of smoke-dried fish.

Keywords

• Allium sativum
• fish
• repellency
• plant oils
• fatty acids
• Cocos nucifera