1Dry Land Institute, Djorf Road, Medenine, 4100 Tunisia.
2Olive Tree Institute, Mahrajène City, Hédi Karray Street, BP 208, 1082 Tunis, Tunisia.
Brazilian peppertree (Schinus terebinthifolius) leaf extract was applied against two strains of the crown gall disease agent (Agrobacterium tumefaciens); strains C58 and AR125. In vitro, we used the agar well diffusion method and the extract was tested in different solvents selected according to their polarity indices, at different concentrations and different incubation temperatures. In vivo, we tested the extract prepared in different solvents on the stems of young tomato plants (cv. Firenze) which were inoculated with the strain C58.The best results were obtained with the extract prepared in hot sterile distilled water and in methanol (0.3 g.ml-1) incubated at 25 °C and 30 °C. The minimum inhibitory concentration (MIC) was evaluated to be 10-4 g.ml-1. In another aspect, to identify the nature of certain substances from S. terebinthifolius leaf extracts, we made a test of fractionation using the Thin Layer Chromatography (TLC) method and phytochemical screening of the crude methanol leaf extract. We noticed the presence of alkaloids and flavonoid compounds which may be responsible for the antibacterial activity. These tests indicated that false pepper leaf extract has an antibiotic effect against Agrobacterium tumefaciens both in vitro and in vivo, which represents a conceptual approach with great promise for future biological control.