It was observed in the walnut nursery of Valle Viejo department - Catamarca, symptoms coinciding with those caused by Agrobacterium tumefaciens circumscribed to the area of ​​the graft. The transmission of the pathogen causing these gills can be by means of tools during the grafting work. The nurserymen disinfect the tools with sodium hypochlorite between 2 and 5%, with the difficulty of deteriorating the blades, leaving them blunt. The objective of the present work was to corroborate the presence of the pathogenic organism that causes the gills observed, and to test, in the laboratory, the effectiveness of different tool disinfectant products. The bacterium was isolated by planting small pieces of gills in two different culture media: Nutritive Agar (AN) and Agar extract of yeast dextrose calcium carbonate (YDC). The ability of four antiseptics to disinfect the graft blade was also evaluated: Sodium Hypochlorite, Glutaraldehyde, 70 ° Alcohol and Quaternary Ammonium, at different concentrations, for 10 and 30 s. Colonies corresponding to A. tumefaciens were isolated and the pathogenicity tests on tomato seedlings reproduced the symptoms. The re-isolations confirm A. tumefaciens as causal agent of the gills in the walnut seedlings examined. The glutaraldehyde at 2% has an efficiency of 100% when submerging 10 s the tool. The glutaraldehyde does not oxidize the tools and does not remove the edge, an advantage over the hypochlorite rejected by the operators because it deteriorates the tools and they must be replaced more frequently.