Preventive and curative application of antagonistic microorganisms in controlling soft rot caused by Rhizopus stolonifer on Moroccan peaches and nectarines in postharvest

The application of biological, inorganic, and chemical treatments significantly reduced both disease incidence and lesion expansion in 'Benedicte' peaches and 'Orion' nectarines. Among the tested biological control agents, the consortium of B. amyloliquefaciens and B. subtilis yielded the most robust inhibitory effect. In peach trials, this combination limited rot incidence to 18.5% in preventive treatments and 20% in curative assays, outperforming single-agent applications. Nectarines showed a similar trend, although overall susceptibility was higher, with minimum incidence levels reaching 27% and 33% for preventive and curative modes, respectively. Morphometric analysis confirmed a consistent reduction in lesion diameter, with values ranging between 28.8 and 35.8 mm in fruits treated with the Bacillus mixture. The observed variations in disease progression between cultivars suggest that host–pathogen interactions are highly dependent on the physiological characteristics of the fruit. These findings underscore the potential of microbial consortia as viable substitutes for conventional fungicides like fludioxonil, aligning with current European regulations for sustainable postharvest management.