Infection risk of Monilinia fructicola on stone fruit during cold storage and immersion in the dump tank

Abstract

Monilinia spp. is the main pathogen responsible for postharvest losses of stone fruit. Several studies have examined the conditions for Monilinia spp. infection in the field, but very limited information is available about postharvest. Storing fruit for 1 day in the cold room or dumping fruit in a water tank are the most common handling operations during the postharvest of fruit. Then, the aim of this study was to investigate the risk of Monilinia fructicola infection for two peach and one nectarine cultivars during cold storage and water dump operations. A new methodology was performed using a dry inoculum of M. fructicola. A set of fruit was used as control to demonstrated that at 20 °C 60% relative humidity (RH) was not able to infect fruit, however, the disease was developed when was already infected. In addition, M. fructicola was able to infect and develop disease in fruit at 20 °C 100 RH. The storage of fruit with the presence of M. fructicola conidia on their surface for up to 30 days at 0 °C 100% RH or 4 °C 100% RH did not suppose an important risk of infection since only 3.3 and 3.8%, respectively of fruit were already infected. Overall, all treatments tested with the water dump operation gave optimal conditions to M. fructicola to infect fruit when it was superficially dry inoculated or it was immersed with water contaminated with conidia, increasing the need for water disinfection. In addition, when fruit was immersed in water free from M. fructicola conidia, the postharvest operation gave optimal conditions to develop infections already produced.