The purpose of the present study was to develop a new method for producing and identifying a bacteriophage suspension and research its potential against plant bacteria. The suspension obtained with the new technique was effective in controlling Xanthomonas campestris PV. campestris both in vitro and in vivo. A difference was observed between the suspension with pathogen (PLP) and crude suspension with lesioned plant without the pathogen originated from it (PLN). Clear zones were observed at 48 h/28^°C in both (PLS) suspension added saccharose and (PLP). Although PLP and PLS treatments showed no statistical difference in CFU values (5 × 105 and 1 × 105, respectively), they differed from the crude suspension (PLN) and the control. Then, in vivo assessment of suspensions with clear zones in the dishes was performed. In vivo (PLPS) and (PLPP) treatments consisting of inoculum were added to the crude suspensions (PLS and PLP) to increase bacteriophages. A decrease in the disease severity index compared to the control was observed, showing that treatment with the phage suspension protects the plant. The lowest disease indexes were reported with (PLP) and (PLS), with values of 1.46 and 1.40, respectively. The highest averages in dry matter (5.1 inboth treatments) were obtained with (PLP) and (PLS) treatments.