The citrus pathogen Xanthomonas axonopodis pv. citri (Xac) can cause extensive damage to twigs, leaves, and fruit of susceptible varieties. The overall objective of this research program has been to develop a bio-control system for citrus canker that utilizes virulent (lytic) phages and/or phage components. Our approach has been to develop a bank of virulent phages and/or antibacterial particles called �tailocins�, which are derived from phages. We have isolated a pool of both type IV and non-type IV dependent phages and tailocins active against Xac. In greenhouse studies, both phage and tailocin cocktails showed efficacy in reducing canker symptoms. We have continued further characterization of phages to confirm their virulent lifestyle by conducting lysogeny testing and sequencing of the genomic termini to determine packaging. Phages CCP504, 505, 511 and 513 have been determined to be virulent. More recently, we have focused on characterization of myophages CCP509 and CCP519 that are both type IV pili dependent. Although both phages are type IV pili dependent, the two phages exhibit differential plating activity, which indicates that their secondary receptor sites are different. Phage CCP509 exhibits activity against 9/13 Xac strains including Xac306, whereas CCP519 has activity against 7/13 Xac strains with some overlap, which makes them good candidates for a phage cocktail. Tailocins XT-1 and XT-4 exhibit broad host range activity, killing 13/13 Xac isolates in vitro and have shown efficacy in greenhouse studies. A tailocin cocktail composed of XT-1 and XT-4 reduced lesion formation by an average of 51%, as compared to non-tailocin challenged plants inoculated only with Xac. In order to minimize the protocol necessary for production of tailocins, we evaluated Carbadox (0-8.5 mM) and hydrogen peroxide (0 -100 mM) two known inducing agents. Carbadox did not induce tailocin production, but 25 mM hydrogen peroxide added to midlog cultures resulted in production of XT-1 and XT-4 equivalent to that observed for UV induction. Our results indicate that hydrogen peroxide can be used as alternative method to UV induction of tailocins, which reduces the steps involved in the production of antibacterial cocktails.