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The bacterium Xanthomonas campestris pathovar musacearum (Xcm) is the causal agent of banana Xanthomonas wilt (BXW). This disease has devastated economies based on banana and plantain crops (Musa species) in East Africa. Here we use genome-wide sequencing to discover a set of single-nucleotide polymorphisms (SNPs) among East African isolates of Xcm. These SNPs have potential as molecular markers for phylogeographic studies of the epidemiology and spread of the pathogen. Our analysis reveals two major sub-lineages of the pathogen, suggesting that the current outbreaks of BXW on Musa species in the region may have more than one introductory event, perhaps from Ethiopia. Also, based on comparisons of genome-wide sequence data from multiple isolates of Xcm and multiple strains of X. vasicola pathovar vasculorum, we identify genes specific to Xcm that could be used to specifically detect Xcm by PCR-based methods.

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Understanding the factors influencing farmers' adoption decisions of the disseminated Banana Xanthomonas wilt (BXW) control package is critical for successful management of the disease. This paper analysed the determinants of farmers' decisions to adopt the control package by smallholder banana farmers in Uganda. A binomial Logit model is applied to household survey data collected from 350 households. Results from the study show that household labour availability, technology package attributes such as labour demand and perceived effectiveness of the practices in managing the disease; and agro-ecological location and banana production system significantly influence adoption decisions. These results suggest the need for adaptation of the technology package to better suit the needs and socio-economic conditions of smallholder farmers through a farmer participatory technology development approach that takes into account research findings, farmers' indigenous knowledge and resource constraints to enhance adoption.

The present study developed a pathovar-specific PCR for the detection of Xanthomonas campestris pv. musacearum (Xcm), the cause of banana xanthomonas wilt, by amplification of a 265-bp region of the gene encoding the general secretion pathway protein D (GspD). A distinct DNA fragment of the expected size was amplified from genomic DNA from all of 12 Xcm isolates tested and no amplification of DNA was observed from other xanthomonads or plant-associated bacteria, including the two closely related species Xanthomonas vasicola pv. holcicola and Xanthomonas axonopodis pv. vasculorum. The Xcm-specific PCR was successfully multiplexed with internal control primers targeting 16S rDNA for application on DNA from bacterial cultures and with primers targeting plant mitochondrial 26S rDNA for application on DNA extracted from plant material. Diagnostic discrimination of healthy and infected plants was subsequently demonstrated in tests on artificially inoculated screenhouse cultivars of banana and field bananas with and without symptoms sampled from different parts of Uganda. This study therefore demonstrated a robust and specific Xcm diagnostic tool with the added advantage of applying internal PCR controls for direct quality assessment of results.