Abstract
Accurate pathogen diagnosis is fundamental for effective crop disease management. In Kenya, a pathogen causing significant damage in potato farms was initially misidentified as Phytophthora infestans. This study aimed to correctly identify this pathogen and explore initial control measures using a polyphasic approach. The methodology integrated morphological observation, pathogenicity testing, and molecular analysis using ITS and EF1-α gene sequencing. The results confirmed the pathogen's identity as Fusarium equiseti, with morphological features consistent with this species and molecular sequencing showing 99.6% identity to reference strains. This is the first official report of Fusarium equiseti as a potato pathogen in Kenya. Furthermore, in vitro assays evaluated the efficacy of native fungal endophytes for biocontrol. Four endophytes inhibited the pathogen's mycelial growth by over 70%, with Trichoderma atroviride isolate ICIPE 710 exhibiting the highest inhibition rate of approximately 91%. This research shows that effective identification of pathogens is crucial for proper management of diseases, ensuring timely control, saving resources and reducing crop losses. This study identified the native endophyte Trichoderma atroviride strain ICIPE 710 as a promising biocontrol candidate. The critical next step is to validate its efficacy in field trials for future development as a sustainable, practical alternative to chemical fungicides.