Xanthomonas Wilt of Bananas in East and Central Africa Diagnostic and Management Guide E. B. Karamura, F. L. Turyagyenda, W. Tinzaara, G. Blomme, F. Ssekiwoko, S. Eden–Green, A. Molina & R. Markham Bioversity International Rome, Italy Bioversity Kampala, Uganda Bioversity International is an independent international scientific organization that seeks to improve the well-being of present and future generations of people by enhancing conservation and the deployment of agricultural biodiversity on farms and in forests. It is one of 15 centres supported by the Consultative Group on International Agricultural Research (CGIAR), an association of public and private members who support efforts to mobilize cutting-edge science to reduce hunger and poverty, improve human nutrition and health, and protect the environment. Bioversity has its headquarters in Maccarese, near Rome, Italy, with offices in more than 20 other countries worldwide. The Institute operates through four Programmemes: Diversity for Livelihoods, Understanding and Managing Biodiversity, Global Partnerships, and Commodities for Livelihoods. The international status of Bioversity is conferred under an Establishment Agreement which, by January 2008, had been signed by the Governments of Algeria, Australia, Belgium, Benin, Bolivia, Brazil, Burkina Faso, Cameroon, Chile, China, Congo, Costa Rica, COte d’lvoire, Cyprus, Czech Republic, Denmark, Ecuador, Egypt, Ethiopia, Ghana, Greece, Guinea, Hungary, India, Indonesia, Iran, Israel, Italy, Jordan, Kenya, Malaysia, Mali, Mauritania, Mauritius, Morocco, Norway, Oman, Pakistan, Panama, Peru, Poland, Portugal, Romania, Russia, Senegal, Slovakia, Sudan, Switzerland, Syria, Tunisia, Turkey, Uganda and Ukraine. Financial support for Bioversity’s research is provided by more than 150 donors, including governments, private foundations and international organizations. For details of donors and research activities please see Bioversity’s Annual Reports, which are available in printed form on request from bioversity-publicationscgiar.org or from Bioversity’s Web site (www. bioversityinternational.org). The geographical designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of Bioversity or the CGIAR concerning the legal status of any country, territory, city or area or its authorities, or concerning the delimitation of its frontiers or boundaries. Similarly, the views expressed are those of the authors and do not necessarily reflect the views of these organizations. Mention of a proprietary name does not constitute endorsement of the product and is given only for information. Citation: E. B. Karamura, F. L. Turyagyenda, W. Tinzaara, G. Blomme, A. Molina and R. Markham. 2008. Xanthomonas wilt of bananas in East and Central Africa. Diagnostic and Management Guide. Bioversity International, Uganda. INIBAP ISBN: 978-2-910810-85-2 Cover photo: William Tinzaara Bioversity International — Headquarters Bioversity — Uganda Via dei Tre Denari 472a P.o. Box 24384 00057 Maccarese Plot 106, Katalima Road, Naguru Rome, Italy Kampala, Uganda © Bioversity International, 2008 Contents Foreword vii Acknowledgements ix 1.0 Bananas in the East and Central Africa (ECA) 1 1.1 Importance of bananas in ECA 1 1.2 Banana varieties and their uses 2 1.3 Challenges to the banana industry in ECA 5 2.0 Xanthomonas wilt of banana in East and Central Africa 9 2.1 Regional distribution 9 2.2 Taxonomy and nomenclature 15 2.3 Disease diagnosis 15 2.3.1 Leaf symptoms 16 2.3.2 Inflorescence symptoms 17 i) Male bud symptoms 17 ii) Fruit symptoms 18 2.3.3 Pseudostem symptoms 20 2.3.4 Confirmatory tests 21 2.4 Disease development and spread 22 2.4.1 Host plants 22 2.4.2 Movement within plants 25 2.4.3 Movement between plants and fields. 27 i) Insects, bats, birds 27 ii) Contaminated tools 27 iii) Infected plant/planting material 28 iv) Grazing animals 29 2.4.4 Survival in soil and plant debris 30 2.5 Control of Xanthomonas wilt of banana 31 iii iv 2.5.1 Raising public awareness 35 2.5.2 Understanding cropping systems (ABB visa-avis AAA) 37 2.5.3 Removing the male bud 40 2.5.4 Disinfecting tools 41 2.5.5 Destruction of infected plant material 44 2.5.6 Use of clean planting materials 44 2.5.7 Host plant resistance/tolerance/escape 45 2.5.8 Exclusion options 46 3.0 Evaluation of the Xanthomonas wilt management guide 48 3.1 Evaluation methods 48 3.1.1 Trainers of trainers evaluation 48 3.1.2 Scoring the criteria 49 3.2 Results and discussion 49 3.3 Conclusion 51 References 52 Plates 57 List of Acronyms 59 Acknowledgements The field work was made possible with the funding extended to Bioversity International by the Catholic Relief Services (CRS) which together with the International Institute of Tropical Agriculture (IITA) executed the Crop Crisis Control Project (C3P) funded by the USAID. The technical team from Bioversity provided significant input into the planning and testing of the tools, and subsequently into the design of the guide. The field testing was carried out in collaboration with National Agricultural Research Organization scientists and Caritas Community-based trainers, who worked with farmers and collected responses, and provided useful criticisms that were incorporated in the final draft. The National Agricultural Research Organization (NARO-Uganda) provided the technical support in terms of tools, laboratory analysis and expertise during the development of the Guide. v Foreword The banana industry in Eastern and Central Africa is a major factor in the region’s food and income security strategy, without which many of the countries would have been net importers of food. Until recently the main biotic threats (weevils, nematodes, fungal and viral diseases) were managed through the use of cultural practices that exploited the differences in resistance / tolerance of the cultivars on farm. In this way farmers suffered reduced productivity but maintained a reasonable level of food and income security. However with the arrival of the Xanthomonas wilt (Xw) of bananas in the region, entire crop holdings were wiped out in some areas where highly susceptible genotypes were dominating the farming systems. A number of national and regional organizations declared the Xw, a priority banana production constraint and appealed for support to control the epidemics that were rapidly developing in the region. The Banana Research Network for Eastern and Southern Africa (BARNESA) steering committee meeting, March, 2001, Nairobi, Kenya, declared Xw as a priority production constraint and appealed for resources to search for a solution to the problem. Later, an impact assessment study conducted in Uganda estimated that up to US$4 billions by 2010 could be lost if no measures were taken to arrest the epidemic. Subsequently, the International Network for the Improvement of Banana and Plantains (INIBAP) (now Bioversity International) in collaboration with the Food and Agriculture Organization of the United Nations (FAO) convened a regional stakeholders’ meeting, February, 2005 and developed a strategy that envisioned multi-disciplinary, multi-sectoral approaches in a coherent regional response. It took into account the countries that were Xw-free but threatened; the frontline areas where the disease had just arrived; and the endemic areas where the disease was already established. vi It also sought to raise the awareness of all stakeholders along the production-consumption chain and empowering them with knowledge and skills for the diagnosis and management of the disease. Hence, awareness-raising and associated training were seen as an integral component of the intervention strategy to control the epidemic and restore productivity in the banana-based farming systems. To achieve this, tools, approaches and innovations were developed and tested to facilitate knowledge generation, learning and sharing in an effort to mobilize stakeholder support and consolidate the fight against the disease. Lessons learnt in the implementation of the regional strategy have been consolidated into the ”Xanthomonas Wilt of bananas in East and Central Africa: Diagnostic and Management Guide” targeting field practitioners (extension providers and planners, researchers and local councils and other policy makers). The guide itself was tested among a cross-section of practitioners from different parts of the region affected by the Xw. It can be used in the development of strategies for stakeholder mobilization, knowledge generation, sharing of information about the disease and training of trainers at country and other levels. In developing the tools, use was made of the wide range of Bioversity experiences with Bugtok (Ralstonia solanacearum) in the Philippines and with Moko (R. solanacearum) in Latin America, both of which have similar symptoms as Xw. Locally, use was made of the experiences gained in Uganda. The tools presented in the guide were deliberately simplified to enable use by a wide range of partners/players. For the same reason a range of management options were proposed to allow practitioners to innovate depending on local circumstances as they use the tools. The regional strategy received a considerable boost with the support of the Crop Crisis Control Project (C3P) funded by the USAID and jointly executed by the Catholic Relief Services (CRS) and the International Institute of Tropical Agriculture (IITA). The project brought together national and regional partners along the production-consumption chain which