Insecticidal and repellent effects of essential oils from leaves of Hyptis suaveolens and Ocimum canum against Tenebroides mauritanicus (L.) isolated from peanut in post-harvest

The present work aims to evaluate the insecticidal and repellent effects of essential oils from fresh leaves of Hyptis suaveolens and Ocimum canum against Tenebroides mauritanicus (L.) (Coleoptera: Tenebrionidaea) isolated from peanut in post-harvest in Benin. Chemical analysis of essential oils by GC and GC-MS indicated that, in the volatile extracts, different groups of terpene and terpenoid were present. The results of contact toxicity tests indicated that at a concentration of 0.5 µl of essential oil/g of peanut the mortality rate of Tenebroides mauritanicus (L.) is 100% after 24 h for the essential oil of Hyptis suaveolens, while it is still at 20% for the essential oil of Ocimum canum. Results also indicated that Hyptis suaveolens oil has a high repellent activity, when compared to the essential oil of Ocimum canum. This essential oil with high repellent and insecticidal properties represents a novel approach in the protection of grains against T. mauritanicus and the reduction of post-harvest losses.