The extensive use of chemicals in plant protection has given rise to concerns about pesticide residues in the environment and to the development of pesticide-resistance by any organisms. Allelopathic plants offer better alternative for this purpose due to being cost-saving, eco-friendly, easy to use, efficient and safe. So, the present work was carried out to evaluate the allelopathic effect of three desert plants (Artemisia judaica, Asphodelus microcarpus, Solanum nigrum) on root knot nematode (Meloidogyne incognita) and three gram negative pathogenic bacterial strains (Erwinia carotovora, Xanthomonas campestris and Ralestonia solanacearum) using root exudates and leaf extracts of each plant with different concentrations. Under laboratory conditions, the data indicated that the three plants contain nematicidal compounds; the inhibitory effect was proportional to the concentrations used. Artemisia judaica extract showed the highest level (100%) of nematicidal activity and indicated good antibacterial activities against all the tested bacterial strains also recorded the best result of minimum inhibitory concentration followed by A.microcarpus root exudate. While the root exudate of A.judaica, S. nigrum had no antibacterial activity, leaf extracts of S. nigrum had weak antibacterial activity. Aqueous leaf extracts of A.judaica appears to be attractive for the development of nematicidal and bactericidal bio- pesticides.