Etude de l’activité biologique de l’huile essentielle et l’extrait hydrométhanoïque des clous de girofle (Syzygium aromaticum) à l’égard du bioagresseur des denrées stockées Trogoderma granarium

Abstract

The use of chemical insecticides against pests of stored food products such as wheat can cause very dangerous problems for human health and the environment. Our study is devoted to the in vitro valorization of hydro-methanoic extract and essential oil of cloves (S. aromaticum) as a botanical insecticide by contact on two larval stages (L4 and L5) of wheat beetle (T. granarium) and their effects on grain germination. The yield of the extract obtained by the Soxhlet technique is estimated at 66.76%, it has a low larvicidal effect with 50% mortality at the most toxic dose 30g/ml after six days of exposure and with a low LD50 (17.67 and 22.54g/ml) marked on L4 and L5 respectively. However, EO has a free yield of 7.52% by the steam entrainment technique; their larvicidal effect is very strong with 100% mortality recorded on L4 and L5 after three days. The lethal concentrations of LD50 and LD90 calculated after 24 hours of EO respectively were very effective (3.39 and 8.11ul/ml). On the other hand, the hydro-methanoic extract was very toxic compared to EO on the germination power of wheat seeds, which means that both showed inhibitory effects on germination when the concentration was increased. They were respectively recorded at levels (48 of 71%). Finally, the insecticidal efficacy of these products needs to be confirmed in vivo