Fusarium equiseti Pathogen of Potato in Kenya and Its Potential In Vitro Biocontrol Using Fungal Endophytes

Accurate pathogen diagnosis is fundamental for effective crop disease management. In Kenya, a pathogen causing significant damage in potato farms was initially misidentified as <i>Phytophthora infestans</i>. 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 <i>Fusarium equiseti</i>, with morphological features consistent with this species and molecular sequencing showing 99.6% identity to reference strains. This is the first official report of <i>Fusarium equiseti</i> 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 <i>Trichoderma atroviride</i> 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 <i>Trichoderma atroviride</i> 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.