Fungal pathogens associated with harvested table grapes in Lebanon, and characterization of the mycotoxigenic genera

Abstract

Table grapes are exposed to fungal infections before and after harvest. In particular, Aspergillus, Penicillium, and Alternaria can cause decays and contamination by mycotoxins. The main fungi affecting Lebanese table grapes after harvest were assessed as epiphytic populations, latent infections, and rots. Effects of storage with and without SO2 generating pads were also evaluated. Representative isolates of toxigenic genera were characterised, and their genetic potential to produce ochratoxin A, fumonisins, and patulin was established. The epiphytic populations mainly included wound pathogens (Aspergillus spp. and Penicillium spp.), while latent infections and rots were mostly caused by Botrytis spp. The use of SO2 generating pads reduced the epiphytic populations and rots, but was less effective against latent infections. Characterization of Aspergillus, Penicillium, and Alternaria isolates showed that A. tubingensis, P. glabrum, and A. alternata were the most common species. Strains of A. welwitschiae and P. expansum were also found to be genetically able to produce, respectively, ochratoxin A plus fumonisins and patulin. These data demonstrate the need for effective measures to prevent postharvest losses caused by toxigenic fungi.

Maturity Assessment of Different Table Grape Cultivars Grown at Six Different Altitudes in Lebanon

“…Lebanon dedicates 70% of its cultivated area for table grape production and 30% for winemaking [ 7 ]. Both local cultivars, including “Beitamouni”, “Tfeifihi”, and “Obeidi”, and imported cultivars, such as Superior Seedless, “Italia”, and Red Globe, are grown in Lebanon and are well adapted to the Mediterranean agroclimatic conditions of this country [ 7 , 8 , 9 ].…”

Postharvest Diseases of Pomegranate: Alternative Control Means and a Spiderweb Effect

“…Indeed, pomegranates are chiefly available from September to February in the northern hemisphere and from April to July in the southern one; therefore, pomegranates are globally scarce in March and August [ 20 ]. Morphological features of pomegranate fruit, such as the persistence of the calyx, remains, and senescent stamens, allow for the setting of latent infections [ 11 , 12 , 21 ], as reported for strawberries and table grapes [ 22 , 23 ]. Indeed, this is one of the leading causes of pomegranate losses, as described by Opara et al [ 24 , 25 ], who analyzed the South African pomegranate trade.…”

Are Basic Substances a Key to Sustainable Pest and Disease Management in Agriculture? An Open Field Perspective

“…Grey mold can result from multiple infection pathways on ripening grape berries, including latent infections established during blooming, direct berry infection due to airborne conidia, and berry-to-berry infection caused by mycelium originating from previously infected berries (nesting path) within the cluster [49,50], which spread according to a nesting path. Although B. cinerea causes about 30% of latent infections [51], it is difficult to precisely estimate the global losses due to its broad host range and specific missing statistics. New Zealand recorded costs due to grey mold direct crop losses and grey mold control measures of up to NZD 5000/ha and NZD 1500/ha, respectively, in growing seasons favorable for disease development [47].…”

“…Currently, latent infections caused by Botrytis spp. are completely prevented in storage through the use of SO 2 -generating pads [51], although these entail adverse effects on food, humans, and the environment (i.e., phytotoxicity, development of antimicrobial resistance, allergy, pollution, etc.) [58], and cannot be applied to organic table grapes.…”