Survey of Fusarium Crown and Root Rot on Tomato (Solanum lycopersicum) in Katsina State, North West Nigeria

Tomato (Solanum lycopersicum) is a critical vegetable crop in Katsina State, where both large-scale and smallholder production contributes to local food security and market supply. Fusarium crown and root rot, caused by Fusarium oxysporum f. sp. radicis-lycopersici and related soilborne Fusarium species, is an increasingly recognised disease complex affecting tomato production in irrigated systems. This undergraduate study surveyed the incidence of Fusarium crown and root rot in tomato fields across five local government areas of Katsina State during the 2023 dry season. Fifty farms were assessed, with diseased plants exhibiting crown canker, root browning, and foliage wilt selected for sampling. Laboratory isolation on selective Fusarium media and pathogenicity testing confirmed F. oxysporum and F. solani as the predominant species associated with crown and root symptoms. Disease incidence averaged 33 percent, with the highest concentrations in fields under continuous tomato cultivation for three or more seasons. Soilborne inoculum levels, estimated indirectly through bioassay, were significantly elevated in monocropped plots compared to rotated fields. Extension interviews revealed that most farmers were unaware of soilborne pathogen dynamics and attributed wilting to water deficit. The study recommends mandatory crop rotation in commercial tomato production schedules in Katsina State and evaluation of soil solarisation as an affordable fumigation alternative. Keywords: tomato, Fusarium crown rot, soilborne pathogen, Katsina State, disease survey.