Integrated Management of Sorghum Grain Mould Complex in North West Nigeria: Pathogen Identification and Control Strategy Evaluation

Sorghum grain mould, caused by a complex of fungi colonising the grain from anthesis to harvest, is a major yield quality constraint in North West Nigeria, reducing food and market value of sorghum grain. The compositional diversity of the mould complex and the comparative efficacy of management strategies under North West Nigerian conditions have not been rigorously evaluated. This study characterised the grain mould fungal complex and evaluated integrated management strategies across sorghum farms in Sokoto, Zamfara, and Kebbi States over two seasons. Grain mould was assessed at physiological maturity using a 1-5 scoring scale, and fungal isolation from 120 mould-affected grain samples was performed on selective media. Integrated management treatments, including fungicide spray at anthesis, resistant variety deployment, early harvest, and their combinations, were evaluated in a factorial field experiment. Fungal isolation identified Fusarium thapsinum, Alternaria alternata, Curvularia lunata, and Bipolaris sorghicola as the dominant grain mould species, with F. thapsinum accounting for 48 percent of isolates across all sites. Resistant variety combined with fungicide spray at anthesis reduced grain mould score by 64 percent and fumonisin contamination levels by 71 percent relative to the susceptible unsprayed control. Early harvest at physiological maturity reduced contamination by 39 percent in all treatment combinations, attributable to reduced grain exposure during the humid post-flowering period. Cost-benefit analysis favoured resistant variety plus early harvest as the most accessible integrated programme for resource-limited farmers. Keywords: sorghum, grain mould, Fusarium thapsinum, integrated management, North West Nigeria.