Effects of Pre-Harvest Spraying with Salicylic Acid (SA) and Sodium Nitroprusside (SNP) on Storage Quality and Pathogenic Fungal Species in ‘Manaohong’ Cherries

Abstract

Chinese cherries, with their delightful blend of sourness and sweetness, are highly favored for their taste and nutritional benefits. However, they mature in conditions of high temperatures and rainfall, making them vulnerable to fungal infections which compromise their post-harvest quality. Our research aimed to study the effects of pre-harvest spraying with salicylic acid (SA) and sodium nitroprusside (SNP) on the pathogenic fungi in Manaohong cherries and their subsequent storage quality. We discovered that using SA and SNP at varying fruit development stages preserved fruit hardness, texture, appearance, and respiratory rate during storage, although it did not significantly alter the fruit’s dimensions. Furthermore, this pre-harvest treatment preserved levels of titratable acids, total phenols, and other antioxidants in the cherries, bolstered the activities of certain antioxidant enzymes (SOD, APX), and inhibited the activity of PPO and POD enzymes.Notably, the SA treatment alone demonstrated superior storage performance compared to combined treatments. Our research also identified Alternaria alternata and Colletotrichum godetiae as the primary pathogens in Manaohong cherries. In in vitro experiments, neither SA nor SNP inhibited these fungi’s growth. Consequently, we evaluated 12 pesticides and determined that 5% hexaconazole and 50% benomyl were most effective against these pathogens. Thus, to enhance the shelf life of Manaohong cherries and ensure their post-harvest quality, we recommend a pre-harvest spray of a SA, and combined with 5% hexaconazole and 50% benomyl. This approach not only promises enhanced cherry longevity but also lays a foundational strategy for the flourishing Manaohong Cherry industry.