Etude préliminaire des activités biologiques (insecticide et antifongique) des huiles essentielles de deux plantes aromatiques Thymus sp. et Origanum sp.

Abstract

As part of a natural resources development, it seemed interesting to study the insecticidal and antifungal action of the essential oils of two aromatic plants Thymus sp. and Origanum sp. pushing to the spontaneous state in Algeria. The present study aims to propose alternative solutions based on the use of natural products to fight against the white grub. The main objective of our work is to verify the effectiveness "in vitro" of the essential oils of Thymus sp. and Origanum sp. on whiteworm larvae and at the same time test their effect on entomopathogenic fungi Beauveria sp. and Fusarium sp .. The results of the first part show that whiteworm larvae are highly sensitive to the effect of Thymus sp. in comparison with that of Origanum sp..The use of thyme to control this pest allowed to observe mortality rates greater than 92% at the 5th day at a dose of 0.031%; while for individuals exposed to the effect of oregano HE less than 61% of the larval population was eliminated on the same day and at the same dose. The analysis of the results of the antifungal activity of the HEs of the two aromatic plants with respect to the entomopathogens Beauveria sp.et Fusarium sp. show that the HE of Thymus sp. has a lower inhibitory capacity for mycelial growth than Origanum for both strains of entomopathogens tested.