Résumé:
This study aims at proposing alternative solutions based on the use of natural products "biopesticides of vegetal origins" In this context, we have evaluated the in vitro insecticidal activity of hydro-ethanoic extracts, hydro- methanoic and synergistic of two toxic plants "Ricinus communis and Sapindus saponaria" on “A. fabae” of beans. The extraction of the crops (Soxhlet method) obtained by the two hydro-ethanolic and hydro-methanolic are (30 and 38%) for R. communis and (22.75 and 27%) are for S. saponaria respectively, while hydro methanoic extract remains the most effective one; these extracts were tested by the direct contact or the toxicity spray method. The biological tests on the insect “A. fabae” has shown that there is a difference between the toxicity of the hydro-ethanoic extracts and the hydro-methanoic ones within the same plant. The synergistic extract caused a remarkable death rate of 100% of this insect. While R. communis and S. saponaria showed the toxicity of 66.67% for hydro-ethanoic extracts and 83.33% for hydro-methanoic. After the fourth day of exposure to the test, the LD50 were very low (less than 3) for the hydro-ethanoic extracts, hydro- methanoic, synergistic of the two plants used.
