Bioactivity of essential oils ofCymbopogon citratus(DC) Stapf andCymbopogon nardus(L.) W. Watson from Benin againstDinoderus porcellusLesne (Coleoptera: Bostrichidae) infesting yam chips

Dinoderus porcellusL. (Coleoptera: Bostrichidae) is a most abundant and damageable pest of stored yam chips in West Africa. In view of the negative effects related to the use of synthetic chemical insecticide, it is important to develop alternative eco-friendly methods of control, such as the use of plant essential oils. The chemical composition and biological effects (repellent, antifeedant, contact and fumigant toxicity) of essential oils fromCymbopogon citratus(DC) Stapf andCymbopogon nardus(L.) W. Watson were evaluated for the first time againstD. porcellus. The chemical composition ofC. citratusessential oil revealed that neral (24.64%), geranial (23.46%), and beta-pinene (21.90%) were the predominant compounds whereas citronellal (37.87%), nerol (19.88%) and citronellol (9.11%) were identified inC. nardusessential oil. Data showed that both essential oils were more effective as repellents and fumigant than the commercial insecticide Actellic 50 EC. The results also revealed the low contact toxicity ofC. citratusandC. nardusessential oils againstD. porcellus. However, similarly to Actellic 50 EC,C. citratusessential oil presented good antifeedant activity againstD. porcellusand reduced yam chips weight loss. The results obtained suggest the good potential of C.citratusas both antifeedant and fumigant toxic agent againstD. porcellus. While,C. nardusessential oil could be recommended as repellent. However, further studies are required to evaluate the insecticidal activity of both Cymbopogon essential oils under farmers' storage conditions and to develop a good formulation as biopesticide.

Automated summary

The study evaluated the chemical composition and biological effects of essential oils from Cymbopogon citratus and Cymbopogon nardus against the pest D. porcellus. Results showed that these oils were more effective as repellents and fumigants compared to the commercial insecticide, but had lower contact toxicity.