The aim of this work was to determine the best extraction method and concentration for Ruta graveolens L. (Rutaceae), Artemisia verlotorum Lamotte (Asteraceae) and Petiveria alliacea L. (Phytolaccaceae) concerning their insecticidal effect against Diabrotica speciosa Germar (Coleoptera: Chrysomelidae). Extracts using commercial soybean oil as at least one of the solvents resulted in higher D. speciosa mortality in controls (solvent = oil) of the three studied plants, relative to their treatment concentrations. R. graveolens extract in water, at 5% concentration, showed higher D. speciosa corrected mortality (32.5%) than A. verlotiorum extracts in water (10% concentration) (20.3%) and P. alliacea in ethanol (2% concentration) (12.5%). The extraction method with water is simple and can be used by small farmers. R. graveolens is an easily cultivated plant and constitutes, therefore, a good alternative to control this plague.
medicinal plants; defoliating beetles; alternative control
