Characterization of stem-end rot pathogens and field evaluation of systemic fungicides in mango orchards of Punjab, Pakistan

Stem-end rot (SER) is a major postharvest disease that limits mango (Mangifera indica L.) production and export potential in Pakistan. This study developed a sustainable SER management framework by integrating pathogen characterization with chemical control strategies. Fungal isolates collected from six districts of Punjab were identified morphologically and molecularly as Lasiodiplodia theobromae, Colletotrichum gloeosporioides, Curvularia spicifera, and Alternaria alternata. Pathogenicity assays confirmed their role in SER, with L. theobromae producing the largest lesions (74.6 mm). In vitro fungicide screening revealed fludioxonil as the most effective compound, inhibiting mycelial growth by 84.6-94.4% across all pathogens at 500-2000 ppm. Field trials showed that fludioxonil at 2000 ppm reduced SER incidence and severity by 87.1% and 92.1%, respectively, compared to untreated controls (71.3% incidence). Azoxystrobin and difenoconazole demonstrated moderate efficacy, while fluoxastrobin was the least effective. Phylogenetic analysis indicated close genetic relatedness between Pakistani isolates and those from India and China, suggesting regional pathogen dispersal. These results establish fludioxonil as a highly effective fungicide for SER management under Pakistani conditions. To mitigate resistance development and enhance sustainability, its use should be integrated with cultural practices and biocontrol agents. Overall, this study provides a science-based, region-specific integrated disease management model to improve mango quality, reduce postharvest losses, and strengthen Pakistan’s export competitiveness.