Characterization of Stemphylium vesicarium isolates from pear orchards in Emilia Romagna (Italy) and assessment of potential microbial biocontrol agents.

Brown spot of pear caused by Stemphylium vesicarium is one of the most important fungal diseases in Europe, as it may cause more than 90 % yield losses. A set of ten S. vesicarium isolates from diseased pear fruits cv. Abbé Fétel, collected in Emilia-Romagna orchards, was molecularly identified, showing high genetic similarity. At pathogenic level, S. vesicarium isolates showed two main degrees of virulence (i. e., “low” and “high”). The most virulent S. vesicarium isolate was then used for assessing the biocontrol of six bacterial isolates, by means of in vitro tests and detached pear fruit assays. The two most promising bacteria, belonging to the genera Bacillus and Pseudomonas, highlighted their potential as putative microbial biocontrol agents for implementing a sustainable control of S. vesicarium.