Taking together our results, we showed the positive effect of application of composted almond shells as organic amendment in biological control of avocado soil-borne pathogen Rosellinia necatrix. In this work, we assigned this biocontrol activity to soil microbial community, where different groups of Gammaproteobacteria, including Pseudomonas spp., were naturally selected. Isolation of culturable members from the suppressive soil of Pseudomonas spp., Serratia spp. and Stenotrophomonas spp., showed the ability of these microorganisms to control the disease index cause by the pathogen, both in avocado roots as in wheat root, using different biological control methods. Due to the importance of genus Pseudomonas sp. in this suppressive soil, and using Pseudomonas spp. previously described by their biocontrol activity against R. necatrix, we design a bacterial consortium in order to improve the knowledge of the putative community interactions that occur during biological control process.