Biological Activity of the Mentha spicata L. and Salvia officinalis L. (Lamiaceae) Essential Oils on Sytophilus granarius L. and Tribolium confusum Jac. Du Val. Infested Stored Wheat

This work is part of the development and enhancement of natural substances and the search for effective, non-polluting and beneficial control methods for human health and for the environment against insect pests of stored cereals. For this purpose, the essential oil extracted by hydro-distillation using Clevenger of aromatic plants Mentha spicata L. and Salvia officinalis L. of the Lamiaceae family, have been tested for a possible effect bio-insecticides, by the method of direct contact against two different species of insect pests of stored cereals belonging to the order Coleoptera: wheat weevil Sytophilus granarius Linnaeus, 1758 (Curculionidae) and confused flour beetle Tribolium confusum Jacquelin du Val, 1863 (Tenebrionidae). This method involves the use of three solutions of essential oils (1ml, 2ml, 10ml of essential oil). 1ml of each solution was applied uniformly to a filter paper disc placed in a petri dish. A batch of adult insect individuals was introduced into each petri dish which was immediately closed and placed in their respective oven. Evaluation of the effectiveness of the product tested: this involves counting the dead individuals daily in the first hours after launching the tests. The test results show that the aerial part of Sage and Spearmint have a toxic effect on adults of Weevil (more than 60% mortality for Spearmint and more than 90% for Sage) and Tribolium (with more than 70% mortality for spearmint and more than 90% for sage). The dose (D3) is the most effective concentration. The insecticidal activity of the essential oil of Spearmint and Sage officinale more effective with respect to both species. In conclusion, these two aromatic and medicinal plants are naturally occurring substances that act as insecticides to control the stored cereals insect pest species.