The Black Shank–Fusarium Wilt disease complex: an emerging threat to tobacco production in Zimbabwe

Tobacco production in Zimbabwe is threatened by the Black Shank–Fusarium Wilt disease complex, an emerging disease due to coinfection by Phytophthora nicotianae and Fusarium species. The first disease case of this complex can be traced back to the 2017–18 season in tobacco samples brought to the Kutsaga plant clinic by farmers. Since then, there has been a steady increase in the incidence of the disease. In the 2023–24 season, some farmers reported up to 40% disease incidences and corresponding high yield losses in their crops. This article describes the characteristics of this emerging disease complex including its causative agents, symptoms, and disease development. It further explores the drivers of disease emergence, control options, and areas that need to be studied to understand the disease better. The major drivers of the emergence of this disease are climate change, globalization, changes in cropping systems, and pathogen evolution. An integrated approach encompassing the use of biological control agents, fungicides, cultural practices, and resistant varieties is practiced in managing the disease complex. The Black Shank–Fusarium Wilt disease complex has the potential to spread to other hosts. Research on developing new resistant varieties, testing of new fungicides, and cultural practices such as the use of biochar, needs to be carried out as part of efforts to control the disease.