Integrating ethnophytopathological knowledge and field surveys to improve tomato disease management in Tanzania

The prevalence of tomato diseases and local smallholder farmer knowledge was assessed in five villages in the Morogoro Region of Tanzania during the rainy and dry production seasons. The most commonly occurring foliar diseases in both seasons were early blight (88 of 100 fields), bacterial spot/speck (49), viral diseases (42) and Septoria leaf spot (34). Bacterial spot/speck, tomato yellow leaf curl virus, other viral diseases, and late blight were present in significantly higher numbers of fields during the rainy season than the dry season, while significantly more plants per field were affected by early blight in the rainy season than the dry season. A root health assay was conducted to assess root knot nematode damage and root rot severity, and root knot nematodes were found in 44 of 50 fields surveyed. Farmers used local names for plant diseases, which tended to be associated with the symptomatology of the disease, concepts borrowed from other aspects of life, perceived causal agent or weather conditions. Identification of local names improved communication between farmers and researchers and elucidated how farmers perceived key diseases in the region. Extension materials were developed to improve farmers’ identification and management of key tomato diseases in the region. Farmers can better allocate limited resources to manage key diseases through an improved understanding of prevalent diseases and local plant disease knowledge. This study serves as an example of how plant pathologists can develop a baseline understanding of key regional plant disease constraints through the integration of field surveys and ethnophytopathological studies.