Impact of Postharvest Handling on Preharvest Latent Infections Caused by Monilinia spp. in Nectarines.

Carlos Garcia-Benitez,Ismael Sánchez-Ramos,Carla Casals,Antonieta De Cal,Josep Usall,Paloma Melgarejo

doi:10.3390/jof6040266

Abstract

Latent infections caused by Monilinia spp. in nectarines cause great economic losses since they are not detected and rejected at harvest and can appear at any time post-harvest, even at the consumer’s home. The effect of a pre-cooling chamber, water dump operation, and cold-storage chamber on the activation and/or development of preharvest latent infections caused by Monilinia spp. on nectarines were studied under different postharvest conditions: (a) cold storage for 0, 1, or 3 d at 4 °C at either 75% relative humidity (RH) or 100% RH before water dumping, (b) water dumping for 10 minutes at 15 °C, and (c) cold storage for 0, 3, or 10 d at 4 °C at either 75% RH or 100% RH after water dumping. These storage conditions were transformed to fungal physiological time. For visualization of the latent infections caused by Monilinia spp., the nectarines were placed in sterile paper bags and frozen at −20 °C for 48 h in order to damage the epidermis. To compare different handling scenarios, the incidence of latent infection was modelled for physiological time description by a modified Gompertz model. The activation and/or development of preharvest natural latent infections caused by Monilinia spp. at postharvest was mainly related to temperature and incubation time at postharvest. Storing nectarines with any postharvest handling less than 11 days at 4 °C avoids brown rot symptoms and reduced the activation and/or development of pre-harvest latent infections caused by Monilinia spp., while more cold days caused the exponential phase of latent infection activation and/or development. The Gompertz model employed could be used for predicting the activation and/or development of latent infection caused by Monilinia spp. at postharvest conditions and looks at the postharvest life. To our knowledge, this is the first time that the effects of post-harvest handling on latent infections in fruit have been studied.

Highlights

Brown rot is an economically important fungal disease of peaches (Prunus persica (L.) Batsch), nectarines (P. persica var. nucipersica (Suckow) C
The natural incidence of latent infections caused by Monilinia spp. in each cultivar before their postharvest handling was determined for each experiment by placing 30 frozen surface disinfected nectarines [11,16] in a humidity chamber lined with sterilized moist filter paper and incubated at 25 ◦ C under fluorescent lighting (100 μE m−2 s−1 with a 16 h photoperiod) for seven days at 100%
The incidence of brown rot in harvested fruit before their handling was determined for each experiment by placing 30 nectarines in a humidity chamber lined with sterilized moist filter paper and incubating them at 25 ◦ C under fluorescent lighting (100 μE m−2 s−1 with a 16 h photoperiod) for seven days at 100% relative humidity (RH)

Summary

Introduction

Brown rot is an economically important fungal disease of peaches (Prunus persica (L.) Batsch), nectarines (P. persica var. nucipersica (Suckow) C. Brown rot is an economically important fungal disease of peaches (Prunus persica (L.) Batsch), nectarines K. Schneid), and other stone fruit species. The main causal agents of brown rot in Spain are Monilinia fructicola (G Winter) and M. laxa M. fructicola has started to displace M. laxa as the major species causing brown rot in the Ebro Valley, Spain [1]. This shift was not associated with an increased disease incidence [2]

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