Characterization of the phytopathogenic fungal community in yellow pitahaya (Selenicereus megalanthus) crops from Boyacá, Colombia

Background and Aims: Yellow pitahaya (Selenicereus megalanthus) is a high-value fruit crop in Colombia, but is highly susceptible to fungal phyto-pathogens affecting stems, flowers, and developing fruits. Improved knowledge of pathogen diversity and characterization is critical for accurate diagnosis and effective disease management. This study aimed to identify and characterize the mycobiota associated with diseases in yellow pitahaya crops in Boyacá, Colombia. Methods: Phytopathogenic fungi were isolated both from symptomatic stem and fruit tissues of yellow pitahaya plants. Samples were surface-ster-ilized and cultured on potato dextrose agar (PDA). Fungal genomic DNA was extracted, and the ITS, LSU, tef1, and BenA gene regions were amplified and sequenced. Taxonomic identification was performed using BLAST and multilocus phylogenetic analysis. Pathogenicity tests were conducted on disinfected cladodes under controlled environmental conditions. Key results: Key pathogens identified included Fusarium foetens, F. guttiforme, F. sterilihyphosum, and Lasiodiplodia specieswere linked to basal stem rot lesions. The bug Leptoglossus zonatus was identified as a vector transmitting F. foetens. Diaporthe species were associated with grayish-orange stem blight, while other fungi like Neofusicoccum, Colletotrichum sp., and Alternaria sp. were isolated from chlorotic lesions. Pathogenicity tests confirmed F. foetens as the cause of stem rot. Molecular analysis revealed that the F. fujikuroi species complex was primarily associated with rot symptoms. Conclusions: Members of the Fusarium fujikoroi species complex were identified in pitahaya fruit as phytopathogenic mycobiota associated to crops in Boyacá, Colombia. This is the first report of Fusarium foetens causing stem rot in pitahaya crops.