Phelipanche aegyptiaca (Egyptian Broomrape) is one of the most important parasitic weeds imposing severe damage on crops especially in Middle East countries such as Iran. In order to study the biological control of broomrape in tomato, outdoor pot experiments were conducted to evaluate the efficacy of bacterial and hormonal treatments in Randomized Complete Block Design with five replications in Agronomy & Plant Breeding Department of University of Tehran, Karaj in 2009 and 2010. The treatments were Pseudomonas strains (UTPF5, UTPF18, UTPF68, and UTPF124), Benzothiadiazole (30 and 60 ppm), salicylic acid, and controls with and without broomrape infestation. The results indicated that Pseudomonas isolate UTPF5 caused an increase (14-fold) in tomato shoot dry weight compared to the infested control. Furthermore, UTPF5 reduced the shoot dry weight, nodules and numbers of broomrape stems, 77, 71 and 50%, respectively. Among Pseudomonas strains, UTPF5 amplified the activity of catalase enzyme and ascrobat peroxidase 1.81- and 9.71-fold, respectively. Benzothiadiazole and salicylic acid, the hormonal treatments, had no meaningful effect on broomrape control and damage reduction. Bacterial strain, UTPF5, which had a significant effect on increasing the tomato yield and reducing the parasite traits, could be useful for developing biological control approaches in combination with other methods against broomrape.
