In this paper, combined application of the plant activator acibenzolar-S-methyl (ASM) and the biocontrol fungus Fusarium oxysporum f. sp. orthoceras (Foo) in an integrated system was evaluated with two sunflower cultivars in a three-factor experiment under greenhouse conditions in order to understand their main effects and interactions on Orobanche cumana control and on sunflower production. The main effects of ASM at 5 mg LS^-1 (litre soil) thrice as soil drenches significantly reduced O. cumana number by 83% and dry matter by 80% and significantly increased sunflower shoot and head dry matter in average of two sunflower cultivars. ASM at 250 g L^-1 thrice as foliar sprays significantly reduced only O. cumana dry matter by 18%. Foo at 1 g LS^-1 significantly reduced O. cumana number by 48% and dry matter by 32% and significantly increased sunflower root and shoot dry matter. Sunflower cv. GO was more susceptible to the parasite than HA89. The interaction between ASM and Foo was highly significantly different on O. cumana number and dry matter and significantly different on sunflower shoot dry matter. In general, the combination of ASM and Foo increased control reliability of O. cumana and improved security of ASM to sunflower. Control of O. cumana in sunflower by ASM was cultivar-dependent. ASM soil drenches combined with Foo were more effective than ASM foliar sprays with Foo.