Control of Olive Tuberculosis Trees with Olive Mill Wastewater: Inhibition of Pseudomonas savastanoi Adhesion

Abstract

This innovative study focused on the threat posed by Pseudomonas savastanoi, the causal agent of olive tuberculosis. This pathogen induces the formation of tumors on the bark and leaves of olive trees, adversely affecting the health of the tree and olive oil production. The objective was to assess the effectiveness of a coating based on olive mill wastewater (OMWW) as a biocontrol agent. Specifically, the study examined its influence on the initial adhesion of P. savastanoi on various olive tree surfaces, including bark and the upper and lower leaf surfaces. The physicochemical characteristics of these surfaces were analyzed by evaluating the contact angle between the bacterial strain and the supports, both before and after treatment with OMWW. The results revealed significant variations in initial bacterial adhesion before treatment, with the lower leaf surface (LSL) showing higher adhesion capacity. However, after treatment with OMWW, initial adhesion decreased by up to 95 %, demonstrating the effectiveness of the coating. Furthermore, OMWW treatment influenced the physicochemical characteristics of all supports, particularly the electron donor character, which significantly reduced initial bacterial adhesion. This underscores the crucial role that surface physicochemical properties play in bacterial interactions, both before and after treatment. These findings provide promising insights for the development of sustainable biocontrol methods aimed at mitigating the impact of olive tuberculosis on the olive oil industry.