Controlling Xanthomonas wilt of banana: Influence of collective application, frequency of application, and social factors on the effectiveness of the Single Diseased Stem Removal technique in eastern Democratic Republic of Congo

Abstract

The continuous cutting of single diseased stems at soil level (Single Diseased Stem Removal - SDSR) reduces Xanthomonas wilt incidence from as high as 80% to below 2% within 3–4 months when applied weekly and collectively by all farmers within a village or landscape. However, various constraints (e.g. labour shortage, absentee farmers, perception on the effectiveness of the technology) may hamper frequent and collective SDSR application. The current study explored effects of varying the intensity of SDSR application in space (collective vs individual/isolated farm application) and frequency of application at mid-high elevations (1400–1800 m a.s.l.) dominated by east African highland bananas. In addition, farmer technology adoption or disadoption (i.e., tried out the technology and then [partially] adandoned it) levels, and the bottlenecks to SDSR application were assessed 6 and 12 months after close of study site, through a survey of farms that participated in the SDSR experiments in east Democratic Republic of Congo (DR Congo). Research results suggest that initial application of SDSR preferably needs to be carried out at regular intervals (i.e. at least weekly) during the first 3–4 months of application, to remove most of the Xanthomonas campestris musacearum (Xcm) inoculum from a field or landscape. This is valid for both collective and individual/isolated disease control approaches. After this phase of rigorous removal of inoculum, frequency of application could be reduced (e.g. to bi-weekly applications), in case e.g. labour is a constraint. With the exception of the weekly SDSR application, collective application relative to the isolated/individual application more rapidly reduced the XW infection levels. An isolated SDSR application compared to collective application did not significantly differ for the weekly SDSR application. Specific level/speed of success will hence mainly depend on frequency of SDSR application. For SDSR, the continuous appearance of diseased plants, even when numbers are very low, over an often large time period, is discouraging small-scale farmers who often want quick results. This is calling for continuous support and training of affected farm communities. Tool sterilization, one of the recommended SDSR package technologies was poorly applied across the sites due to damage caused to metal farm tools by fire. Novel approaches of tool sterilization thus need to be explored.