Plant diseases need to be effectively controlled to support a constant production of food and feed worldwide. Plants can be affected by viral, bacterial and fungal dieses.  Common practices for controlling bacterial plant pathogens involve application of chemical bacteriocides. These techniques, however, are not sustainable and lead to environmental pollution that is becoming a major health concern connected to agricultural practices worldwide.  We here propose to develop a new, sustainable, green-tech approach for biological control of bacterial plant diseases. The approach is based on the natural viral enemies of bacterial pathogens, the bacteriophages. We will use newly developed sequencing based methods to discover, isolate and characterize hundreds of new bacteriophages. Ultimately, formulated cocktails of new bacteriophages will be tested and applied in lab settings to prevent and treat the seven most crop-destroying and costly bacterial plant diseases known today.