Current status and determinants of tomato Fusarium wilt ( <i>Fusarium oxysporum f. sp. lycopersici</i> ) epidemics under high-tunnel production system in northwest Ethiopia

Abstract Background : High-tunnel tomato cultivation technology is vital for year-round production during the rainy season and for enhancing income among smallholder farmers in north-west Ethiopia. However, its productivity and sustainability are adversely affected by Fusarium wilt (FW) disease. This study assessed the current status of FW epidemics, examined associated biophysical factors, and characterized Fusarium oxysporum f. sp. lycopersici (FOL) isolates during the 2024 main cropping season. Methods : A total of 75 high-tunnel technologies were inspected in four major tomato-producing districts within two zones. A logistic regression model was used to associate biophysical factors with disease incidence and severity. Results : All the surveyed high-tunnels were infected with FW, with incidence ranging from 43.6% (Libo Kemkem) to 60.5% (Dera), and severity from 41.4% to 58.3%. Disease incidence and severity were strongly correlated (P &lt; 0.001) with district, age and leakiness of high-tunnels, seed type and source, plant and weed density, crop rotation, and irrigation method. Elevated incidence and severity (&gt;50%) were notably associated with Dera district, gray soils, older and leaky high-tunnels, local and unknown seed varieties, informal seed exchange, high plant and weed density, fruit-setting stage, absence of crop rotation, and contact irrigation method. Pathogen isolation and characterization study identified eight morpho-culturally and pathogenically diverse FOL isolates. Conclusion : FW exhibits extensive distribution across high-tunnel technologies, driven by various biophysical factors and has diverse strains. Therefore, integrated management strategies, including cultural interventions and resistant varieties, are imperative for sustainable high-tunnel tomato production in the study area. Further research on temporal pathogen dynamics and molecular characterization of isolates is also recommended.