Abstract

Postharvest losses due to fungal pathogens pose a significant challenge, impacting the quality, quantity, and market value of agricultural commodities throughout the food supply chain. Despite the substantial consequences of these losses, a critical knowledge gap exists, particularly in identifying the fungal pathogens responsible for postharvest diseases in apples in Nasir Abad, Hunza Valley, Gilgit Baltistan (GB). In this study, approximately 15 fungal isolates were recovered from stored apples. Each isolate, labeled from "Asp-A-1" to "Asp-A-15," was characterized and assessed for its impact on apple fruits. The growth rates of Aspergillus sp. isolates were investigated. Asp-A-2 emerged as the fastest-growing isolate with a mean radial growth of 59.3 mm, while Asp-A-6 exhibited the slowest growth rate at 39.27 mm. The remaining isolates demonstrated intermediate growth rates, providing valuable insights into their varied growth characteristics. Pathogenicity testing was conducted to evaluate the impact of fungal isolates on both wounded apple fruits (WAF) and non-wounded apple fruits (NWAF). Among the isolates, Asp-A-2 exhibited the highest pathogenicity, causing significant damage with WAF and NWAF values of 91.7% and 25.4%, respectively. Asp-A-8 also demonstrated notable pathogenicity, with WAF and NWAF values of 86.4 and 22.9%. Isolates Asp-A-7 and Asp-A-14 displayed moderate pathogenicity, while Asp-A-1 and Asp-A-10 showed lower levels of pathogenic impact. Asp-A-12 and Asp-A-13 exhibited similar levels of pathogenicity. In conclusion, these findings contribute to understanding the complex interactions between Aspergillus sp. isolates and apple fruits, offering insights into potential strategies for managing postharvest losses in apple production in Gilgit Baltistan.