Potato bacterial wilt in Rwanda: occurrence, risk factors, farmers’ knowledge and attitudes

Abstract

Potato is an important food commodity and efforts to increase its productivity should focus on addressing production limiting factors. Potato bacterial wilt (PBW) caused by Ralstonia solanacearum is one of the major constraints to potato production in Rwanda and no single method effectively controls the disease. Development of a sustainable management approach requires understanding of PBW distribution, risk factors, farmers' knowledge and management attitudes. Therefore, we surveyed PBW disease and interviewed farmers in eight districts of Rwanda during March-April 2015. We detected PBW in all the surveyed districts and it was ranked as the major potato disease constraint. Among districts, disease incidence and severity varied from 5 to 24% and 3 to 13%, respectively, and was significantly higher in minor compared to major potato growing districts. Low PBW incidence and severity were associated with high altitude and low planting density, intercropping, crop rotation and avoidance of sharing farm tools. In all districts, farmers had little knowledge about PBW detection and spread, and the farmers' awareness of PBW management was often inconsistent with their practices. This incomplete knowledge about PBW was likely caused by inadequate extension services since most information about PBW was acquired from fellow farmers, parents or other relatives. Thus raising awareness of PBW and integrated disease management, including practices that are associated with low PBW, could limit the impact of this disease and help to secure food and income for potato growing farmers in Rwanda.

Ralstonia solanacearum causing potato bacterial wilt: host range and cultivars’ susceptibility in Rwanda

“…The incidence was calculated as the percentage of wilted plants per total number of inoculated plants. The percentage severity was calculated by transforming severity scale data where 1 = no symptoms, 2 = one or two leaves wilted, 3 = half of the leaves wilted, 4 = almost all leaves wilted, 5 = the whole plant died (Horita and Tsuchiya, 2001) into percentage wilting, where 1 = 0%, 2 = 20%, 3 = 50%, 4 = 75%, 5 = 100% (Uwamahoro et al, 2018). Scientific), 1× DreamTaq buffer, and MgCl 2 added to a final concentration of 3.5 mM.…”

“…Potato bacterial wilt, also named southern bacterial wilt or brown rot, caused by some members of the Ralstonia solanacearum species complex (RSSC), is a limiting factor for potato production in Rwanda. The disease is widespread in the country and about 24% disease incidence has recently been reported (Uwamahoro et al , ).…”

“…The potato plant has a short growth cycle and can easily be integrated into existing agricultural systems. Potato growers in Rwanda are mainly smallholder farmers, cultivating <1 hectare, and the crop is grown either in pure stand, rotated or grown in intercropping systems with other crops (Uwamahoro et al , ). A number of crops and other plant species grown together with or adjacent to potato crops could serve as hosts for important pests and pathogens of potato.…”

“…The potato plant has a short growth cycle and can easily be integrated into existing agricultural systems. Potato growers in Rwanda are mainly smallholder farmers, cultivating <1 hectare, and the crop is grown either in pure stand, rotated or grown in intercropping systems with other crops (Uwamahoro et al, 2018).…”

Management strategies for banana Xanthomonas wilt in Rwanda include mixing indigenous and improved cultivars

“…The relationship between Xanthomonas wilt incidence or severity with independent variables was tested in single, multiple, and reduced models (Uwamahoro et al 2018) by using logistic regression in R statistical software (Everitt and Hothorn 2006). Thirteen independent variables were used and categorized into variable classes.…”