Understanding Biotic Constraints to Taro (Colocasia esculenta) Production in the Derived Savanna and Humid Forest Agroecosystems of Nigeria

Taro (<i>Colocasia esculenta</i>) is a socioeconomically and nutritionally important crop that is predominantly cultivated in the derived savanna and humid forest agroecosystems of Nigeria. Taro production in the country has declined since the taro leaf blight (TLB) outbreak caused by <i>Phytophthora colocasiae</i> Raciborski. This study conducted field surveys during the 2021-2022 production season to assess the status of taro diseases, as well as a structured questionnaire to capture farmers' management practices and the socio-economic determinants of taro cultivation across seven major taro-producing states in Nigeria. Data was collected from 63 randomly selected farmers across 53 farms, and 449 corms were sampled from farms and markets to assess corm-borne diseases. Sixty-three percent of farmers identified biotic constraints as the major production challenge, with TLB recognized as the most significant threat. Virus-symptomatic plants were not observed in the farmers' fields, but the occurrence of Dasheen mosaic virus (or <i>Potyvirus dasheenis</i>) (DsMV, genus <i>Potyvirus</i>) was detected among the plants regenerated from corms collected from farms and markets. The widespread occurrence of TLB and DsMV suggests that these two pathogens pose a serious threat to taro production and that there is a risk of further spread through the continuous recycling of self-sourced planting materials across seasons.