Developing a National Early Warning System for Crop Disease Epidemics in Nigeria: A Data-Driven Modelling and Governance Framework

Epidemic crop diseases impose unpredictable and severe economic shocks on Nigerian agriculture, yet no operational national early warning system exists to provide advance notice of disease risks to farmers, extension services, and policymakers. The development of such a system requires integration of epidemiological modelling, remote sensing, climate forecasting, and governance design in a technically and institutionally coherent framework. This doctoral research develops both the technical architecture and the governance framework for a national crop disease early warning system applicable to Nigeria's major food crop pathosystems. The technical development encompasses: retrospective analysis of 20 years of disease outbreak data from Nigeria's state agricultural development programme archives; development and validation of climate-driven early warning algorithms for four priority pathosystems, including cassava mosaic disease, rice blast, maize stem rust, and groundnut aflatoxin; integration of MODIS and Sentinel-2 satellite-derived stress indices as proxies for pre-epidemic crop susceptibility; and prototype design of a mobile and web-accessible warning delivery platform with tiered alert levels calibrated to extension response capacities. The governance component applies adaptive management and multi-actor governance theories to design an institutional architecture for warning system operation that is functional within Nigeria's current federal structure and plant health agency landscape. Validation trials across sentinel farms in Kano, Benue, and Ogun States assess warning lead times and farmer response behaviour. The research delivers an original early warning model framework, governance blueprint, and validated pilot system representing a concrete solution to a documented national plant health infrastructure gap. Keywords: early warning system, crop disease, epidemiological modelling, Nigeria, governance.