Fusarium wilt of banana, a recurring threat to global banana production

TR4 first emerged in Southeast Asia (Ploetz, 1990) and its current rapid spread was analysed by Ordóñez et al. (2015). Subsequent studies showed that the TR4 strain is extremely virulent towards many banana cultivars, including Cavendish cultivars grown in large-scale monoculture plantations for export markets and many banana varieties important for food security and domestic consumption. There are no readily available solutions to manage this disease. Moreover, this global threat connects export trade, strongly dependent on the susceptible Cavendish cultivars, to local production systems wherein a range of banana varieties contributing to food security are also impacted.This research topic aims to provide a platform for information exchange and knowledge sharing. The contributions demonstrate an active research community in search of effective control of FWB. Taken together, the papers provide an overview of our current understanding of the biology and epidemiology of TR4, its management and how integrated and innovative solutions are required and need to be embraced by all stakeholders in an effort to build a sustainable banana industry for the future

Fusarium Wilt of Banana: Current Knowledge on Epidemiology and Research Needs Toward Sustainable Disease Management

Banana production is seriously threatened by Fusarium wilt (FW), a disease caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc). In the mid-twentieth century FW, also known as “Panama disease”, wiped out the Gros Michel banana industry in Central America. The devastation caused by Foc race 1 was mitigated by a shift to resistant Cavendish cultivars, which are currently the source of 99% of banana exports. However, a new strain of Foc, the tropical race 4 (TR4), attacks Cavendish clones and a diverse range of other banana varieties. Foc TR4 has been restricted to East and parts of Southeast Asia for more than 20 years, but since 2010 the disease has spread westward into five additional countries in Southeast and South Asia (Vietnam, Laos, Myanmar, India, and Pakistan) and at the transcontinental level into the Middle East (Oman, Jordan, Lebanon, and Israel) and Africa (Mozambique). The spread of Foc TR4 is of great concern due to the limited knowledge about key aspects of disease epidemiology and the lack of effective management models, including resistant varieties and soil management approaches. In this review we summarize the current knowledge on the epidemiology of FW of banana, highlighting knowledge gaps in pathogen survival and dispersal, factors driving disease intensity, soil and plant microbiome and the dynamics of the disease. Comparisons with FW in other crops were also made to indicate possible differences and commonalities. Our current understanding of the role of main biotic and abiotic factors on disease intensity is reviewed, highlighting research needs and futures directions. Finally, a set of practices and their impact on disease intensity are discussed and proposed as an integrative management approach that could eventually be used by a range of users, including plant protection organizations, researchers, extension workers and growers

Aspects of current research to combat Fusarium wilt of banana with a special focus on TR4. Brief proceedings of an RTB virtual mini-symposium. FP3 Resilient Crops - Cluster BA3.3 Fungal and Bacterial Wilts.

Sharing both recent research results and plans for future studies are vital components of RTB’s strategy to contribute to tackling the threat posed by Foc TR4, and it was for this reason that researchers from BA3.3 convened a mini symposium entitled ‘Aspects of current research to combat Fusarium Wilt of banana with a special focus onTR4’. This brought together more than 60 researchers from across the world for a two-day virtual exchange of cutting-edge research presentations and discussion. Importantly, the results presented are to be published through a special issue of the Journal of Fungi. The work presented in this booklet, which summarizes the proceedings of the mini symposium, constitutes cutting-edge research to address the challenges posed by Foc TR4 that threatens Cavendish as well as other key susceptible cultivars. The research reveals new insights into the spread of Foc TR4 in southern Africa, the Greater Mekong Delta, and Latin America; evaluating biocontrol agents; the survival of Fusarium spores in water; the effects of nematodes and weevils in pathogen spread and infection; and in breeding for resistance. There are great opportunities to harness potential synergies from the many complementarities revealed in the symposium, and a need to scale the research from in vitro to field studies, with the ultimate goal of implementing scalable findings at farm and plantation level. Fusarium wilt will continue to be a challenge for banana producers in the near future. However, as control technologies described here are scaled out, there is real hope that production of what is one of humanity’s most treasured fruits will be restored and that livelihoods of all those that depend on it will be enhanced

Evaluación de diferentes somaclones de papa para la resistencia a Alternaria solani Sorauer, mediante el uso de la inoculación artificial en condiciones de campo

The use of plant pathogens, for the genetic improving programs is an important matter to guarantee its success. Utilization of phytopathogenic isolates from natural source, let us to employ rapid screening in some important genotypes. In this work it was used a mycelium homogenizated of Alternaria solani Sor (strain IBP-As-4), with a relative concentration of 1.7x105 ufc ml-1. The inoculum was applied by spraying to the somaclons (obtained by mutagenic and in vitro selection with culture filtrated of the fungus), also to the susceptible (Desireé) and resistant (Solanum chacoense) cultivars, respectively. The first symptoms appeared after seventh day of inoculation. The behavior between somaclons and testers in the final evaluation were different. Solanum chacoense was the most resistant genotype, the somaclons IBP-93 and IBP-38 were more susceptible than Desireé. The somaclons IBP-27 reached a similar affectation score respect to Solanum chacoense. The rest of the somaclons had an intermediate performance. It was proved the important of using of pathogenic strains of Alternaria solani Sor, for making selection where the natural inoculum source it is weak.Key words: genetic, improvement, selection, Solanum tuberosum L.El uso de microorganismos fitopatógenos en los programas de mejoramiento genético es de vital importancia para garantizar el éxito de los mismos. La utilización de aislados patogénicamente representativos de condiciones naturales permite estudiar genotipos promisorios respecto a las diversas enfermedades de interés económico. En el presente trabajo se utilizó como inóculo artificial un homogeneizado micelial de la cepa IBP As-4 (Alternaria solani Sorauer) con una concentración de 1.7x 105 ufc.ml-1. El mismo fue aplicado mediante aspersión foliar a diferentes somaclones de papa de la variedad Desireé, obtenidos por mutagénesis y selección in vitro. Los primeros síntomas aparecieron a los siete días después de efectuada la inoculación. Se observaron diferencias respecto al desarrollo de los síntomas entre los somaclones y los testigos en las distintas evaluaciones. Solanum chacoense se comportó como el genotipo más resistente mientras que los somaclones evaluados registraron valores intermedios, aun cuando algunos de ellos alcanzaron grados de afectación promedio superiores al testigo Desireé. Se pudo comprobar la importancia del empleo de la inoculación artificial para efectuar la selección de individuos promisorios donde la presión de inóculo sea débil.Palabras clave: mejoramiento genético, selección, Solanum tuberosum L., tizón tempran

Bacterial diseases of bananas and enset: Current state of knowledge and integrated approaches toward sustainable management

Bacterial diseases of bananas and enset have not received, until recently, an equal amount of attention compared to other major threats to banana production such as the fungal diseases black leaf streak (Mycosphaerella fijiensis) and Fusarium wilt (Fusarium oxysporum f. sp. cubense). However, bacteria cause significant impacts on bananas globally and management practices are not always well known or adopted by farmers. Bacterial diseases in bananas and enset can be divided into three groups: (1) Ralstonia-associated diseases (Moko/Bugtok disease caused by Ralstonia solanacearum and banana blood disease caused by R. syzygii subsp. celebesensis); (2) Xanthomonas wilt of banana and enset, caused by Xanthomonas campestris pv. musacearum and (3) Erwinia-associated diseases (bacterial head rot or tip-over disease Erwinia carotovora ssp. carotovora and E. chrysanthemi), bacterial rhizome and pseudostem wet rot (Dickeya paradisiaca formerly E. chrysanthemi pv. paradisiaca). Other bacterial diseases of less widespread importance include: bacterial wilt of abaca, Javanese vascular wilt and bacterial fingertip rot (probably caused by Ralstonia spp., unconfirmed). This review describes global distribution, symptoms, pathogenic diversity, epidemiology and the state of the art for sustainable disease management of the major bacterial wilts currently affecting banana and enset. (Résumé d'auteur

Melhoramento genético da bananeira: estratégias e tecnologias disponíveis

A banana cultivada 107 países, em uma área de 4,1 milhões de hectares e produção de 95 milhões de toneladas, é segunda fruta mais produzida do mundo. A bananeira é atacada por vírus (CMV e BSV), fungos (Sigatoka amarela e negra, mal-do-Panamá), bactéria (Moko), nematoide e insetos (Broca do rizoma). No entanto, por meio do melhoramento genético é possível obter resistência a maioria das pragas e doenças. O centro de origem de grande parte do germoplasma de Musa spp. é o Continente Asiático, onde são encontradas bananeiras diploides, triploides tetraploides, com genomas de Musa acuminta e M. balbisiana. No melhoramento de banana, feito principalmente para resistência às doenças, são usados os seguintes métodos: introdução e seleção de clones; hibridação (cruzamentos de diploides com diploides, triploides com diploides e diploides com tetraploides); duplicação de cromossomos; mutação e transgenia. Os métodos que envolvem hibridação, embora sejam os mais usados, apresentam limitações como a partenocarpia, a esterilidade; o número variável de ploidia e a baixa produção de sementes. Todo material produzido no programa, é depois avaliado nas regiões produtoras de banana. Atualmente novas técnicas de melhoramento, baseadas em informações genéticas de Musa spp. estão sendo incrementadas

Sistemas de producción de musáceas en Perú

Este documento se elaboró como parte de las actividades del proyecto “Fortaleciendo conocimientos, capacidad de diagnóstico y buenas prácticas frente a la amenaza de Fusarium y otros problemas fitosanitarios para las familias productoras de plátanos del Perú”, implementado por la Alianza de Bioversity International y el CIAT, el Instituto Nacional de Innovación Agraria (INIA), el Servicio Nacional de Sanidad Agraria (SENASA) y la Secretaría Técnica de CGIAR en Perú. Está orientado a productores, estudiantes, técnicos y profesionales del rubro musáceas, que buscan ampliar sus conocimientos y fortalecer sus capacidades técnicas para mejorar la toma de decisiones en los sistemas productivos de estos cultivos

Ex-ante assessment of returns on research investments to address the impact of Fusarium Wilt tropical race 4 on global banana production

The spread of Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), causal agent of Fusarium wilt of banana (FWB), has been projected to reach 17% of the global banana-growing area by 2040 equaling 36 million tons of production worth over US$10 billion. This potential loss has fueled (inter)national discussions about the best responses to protect production and small-scale growers’ livelihoods. As part of a multi-crop ex ante assessment of returns on research investments conducted by the CGIAR Research Program on Roots, Tubers, and Bananas (RTB) from 2012 to 2016, four FWB research options were assessed: (i) improved exclusion, surveillance, eradication, and containment (ESEC) measures to reduce Foc TR4 spread, (ii) integrated crop and disease management (ICDM) to facilitate production of partially FWB resistant cultivars on Foc-infested soils, (iii) conventional breeding of FWB-resistant cultivars (CBRC), and (iv) genetically modified (GM) FWB-resistant cultivars (GMRC). Building on a risk index (Foc scale) predicting the initial occurrence and internal spread of Foc TR4 in 29 countries, an economic surplus (ES) model, cost-benefit analysis, and poverty impact simulations were used to assess impact under two adoption scenarios. All options yield positive net present values (NPVs) and internal rates of return (IRRs) above the standard 10% rate. For the conservative scenario with 50% reduced adoption, IRRs were still 30% for ICDM, 20% for CBRC, and 28% for GMRC. ESEC has IRRs between 11 and 14%, due to higher costs of capacity strengthening, on-going surveillance, farmer awareness campaigns, and implementation of farm biosecurity practices, which could be effective for other diseases and benefit multiple crops. The research investments would reach between 2.7 million (GMRC) and 14 million (ESEC) small-scale beneficiaries across Asia/Pacific, Sub-Saharan Africa, and Latin America/Caribbean. The options varied in their potential to reduce poverty, with the largest poverty reduction resulting from CBRC with 850,000 and ESEC with 807,000 persons lifted out of poverty (higher adoption scenario). In the discussion, we address the data needs for more fine-grained calculations to better guide research investment decisions. Our results show the potential of public investments in concerted research addressing the spread of Foc TR4 to yield high returns and substantially slow down disease spread