Potential use of essential oils from local Cameroonian plants for the control of red flour weevil <i>Tribolium castaneum</i> (Herbst.) (Coleoptera : Tenebrionidae)

Abstract

Animal feed is food constituted for breeding stock animals because it possesses vital nutrients for animal growth. Animal feed or their ingredients as constituted by cereal flour and are stored after formulation for ulterior breeds. These provender or cereal grains used are commonly attacked by storage insects principally of the genus Tribolium. Firstly, contact and ingestion test by two essential oils of aromatics plants Ocimum gratissimum L (Lamiaceae) and Xylopia aethiopica Dunal A. Rich (Annonaceae) were done firstly on adults and aged larvae of Tribolium castaneun. Secondly, the contact and inhalation test by three essential oils of the aromatic plants Annona senegalensis L. (Annonaceae), Lippia rugosa L.  (Lamiaceae) and Hyptis spicigera Lam. (Verbenaceae) were done for the control larvae, young and aged adults of the red flour weevil Tribolium castaneum Herbst (Coleoptera : Tenebrionidae) very resistant pest to chemical pesticides. Essential oils of Ocimum gratissimum and Xylopia aethiopica have no contact and  ingestion effect on adults of Tribolium castaneum; their insecticidal activity is characterized mostly by their inhibition of the  nymphosis of aged larvae of the same species. On the other hand contact and inhalation tests with crude essential oils of Lippia rugosa and Hyptis spicigera are the most promising because of their efficacy on the other life stages. They are more efficient, with 100% mortality, on larvae at early  stages and young adults. On resistant aged larvae and adults, the insecticidal  efficacy decreases but remains significant. Since this insect, Tribolium castaneum is the major pest of stored flours and provender, the incorporation of these  promising essential oils in flours or in storage formulations of these foods for animals could contribute to their better cereal food conservation. The important and indispensable element of cereals for storage, growth and reproduction animal feed could be preserved from insects attack by use of natural product and may  contribute to diminish toxicity of feeder, environmental pollution and the resistance phenomenon of insects.

Key words: Essential oils, Tribolium castaneum, Pesticides.