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Fusarium wilt of banana (FWB), caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc), poses an undeniable threat to global banana production. This disease has intensified in recent years, with the tropical race 4 (TR4) strain spreading rapidly. Since 2018, the number of affected countries has increased from 16 to 23, presenting a significant challenge to researchers, producers, and National Plant Protection Organizations (NPPOs) worldwide. The potential impact of TR4 in Latin America and the Caribbean (LAC) is particularly concerning. This region boasts seven of the top ten banana-exporting countries, and bananas and plantains are crucial for food security and income generation. In Colombia, where TR4 was detected in 2019, the disease has already spread from La Guajira to Magdalena, and it is currently affecting 20 large commercial export farms. In Peru, the disease was detected in 2021 and although still restricted to the northern region, flood irrigation and heavy rains associated with the Yaku cyclone, boosted pathogen spread, and more than 400 small organic banana farmers are currently affected. In Venezuela, TR4 detection occurred in 2023, with plantations across three states and five municipalities now affected. Worryingly, TR4 has also been confirmed in plantains, a staple food in the region. Current national responses in LAC primarily rely on preventive and reactive measures: preventing initial incursions and containing outbreaks to avoid further spread. However, the disease's relentless progression suggests that its eventual presence in all banana-producing areas is likely. Therefore, exploring alternative management approaches beyond pathogen exclusion becomes crucial, both in affected and disease-free regions. This paper examines the current spread of TR4, focusing on epidemiological aspects and recent research-based management options. Key epidemiological features were highlighted, drawing practical examples from various scales (plots to landscapes) and utilizing experiences from LAC's fight against TR4. The paper also reviews field-tested approaches in biosecurity, biological control, resistant varieties, soil health, and integrated disease management, acknowledging the specific challenges faced by smallholder settings. In each section research initiatives were analyzed, identifying gaps, and proposing directions to minimize TR4 impact and accelerate the development of sustainable solutions for managing this devastating disease.
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Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is the causal agent of Fusarium wilt, a major threat to the banana industry worldwide. Here, we report the genome of a Foc TR4 strain from Peru, sequenced using a combination of Illumina and Oxford Nanopore Technologies.
RESUMO
BACKGROUND: Entomopathogenic fungi can provide a set of ecological services, such as suppressing arthropod pests and plant pathogens. In this study, novel indigenous Beauveria caledonica (Bc) strains were isolated from naturally infected banana weevils (Cosmopolites sordidus) occurring in commercial banana plantations in Brazil. RESULTS: The prevalence of infection by Bc strains on field-caught C. sordidus ranged from 1.3% to 12.9%. Similar to the Beauveria bassiana strains tested, none of the Bc strains caused more than 50% weevil mortality at a concentration of 1 × 108 conidia ml-1 . Bc strain CMAA1810 caused the highest mortality in C. sordidus and had enhanced insecticidal activity when formulated with an emulsifiable oil. In paired co-culture assays, this same strain showed a significant growth-inhibitory effect on the causal agent of Fusarium banana wilt (Fusarium oxysporum f. sp. cubense, Foc) of twofold magnitude compared with the control. Cell-free crude filtrates derived from the red-pigmented culture broth of Bc (CMAA1810) strongly reduced Foc conidial viability, and this inhibitory activity was inversely related to the age of the Bc culture. Crude concentrated filtrates from 4-day-old cultures exhibited the strongest antifungal activity (13-fold) compared with untreated Foc conidia. The abundant compound identified in the crude filtrate of Bc was oosporein (1,4-dibenzoquinone) present at a concentration of 0.829 ± 0.018 mg g-1 dry matter, and the antifungal activity of the filtrate was demonstrated. CONCLUSION: These results indicated that Bc strains might have the potential to manage both C. sordidus and Foc, two of the major phytosanitary problems in banana crops worldwide. Further research under field conditions using suitable formulations of virulent Bc strains in combination with the metabolite oosporein is needed to evaluate their efficacy in the management of C. sordidus and Foc in banana plantations. © 2022 Society of Chemical Industry.
Assuntos
Beauveria , Fusarium , Musa , Gorgulhos , Animais , Antifúngicos/farmacologia , Benzoquinonas , Musa/microbiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Esporos Fúngicos , VirulênciaRESUMO
Fusarium wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. cubense (Foc), is considered one of the most destructive diseases of bananas in Brazil. In this study, a collection of 194 monosporic isolates from several banana-producing regions located in different climatic zones along a south-to-north transect in Brazil was formed to assess the genetic structure of the population of Foc. The isolates underwent pathogenicity tests, PCR diagnosis for the detection of tropical race 4, and screening of SIX homolog genes that produce putative effector proteins. The vegetative compatibility group (VCG) of 119 isolates was determined by pairing against 17 internationally known VCG-tester strains. A group of 158 isolates was selected for simple sequence repeat (SSR) genotyping. There was moderate diversity of Foc in Brazil. Eight VCGs were identified: 0120, 0122, 0124, 0125, 0128, 01215, 01220, and 01222, of which 78% of isolates belong to a single VCG, whereas 22% of isolates are assigned to multiple VCGs, belonging to complexes of VCGs. The distribution of VCGs is uneven and independent of the banana genotype. The isolates of a VCG shared a similar profile of SIX homologs, but there was no association with geographic region. Four SSR loci were polymorphic, and, on average, 7.5 alleles were detected per locus. Thirty-five multilocus genotypes (MLGs) were identified. There was no association between VCG and MLGs, and no genetic structure of the population of Foc in Brazil was detected.
Assuntos
Fusarium , Musa , Brasil , Doenças das Plantas/microbiologia , Musa/microbiologiaRESUMO
The effective management of Fusarium wilt of bananas (FWB) depends on the knowledge of the disease dynamics in time and space. The objectives of this work were: to estimate disease intensity and impact, and to investigate the spatial and temporal dynamics of FWB. Fields planted with Silk (n = 10), Pome (n = 17), or Cavendish (n = 3) banana subgroups were surveyed in Brazil, totaling 95 ha. In each field, all plants were visually assessed, and diseased plants were georeferenced. The incidence of FWB and the impact of the disease on the yield on a regional scale were estimated. Spatial patterns were analyzed using quadrat- and distance-based methods. FWB incidence ranged from 0.09% to 41.42%, being higher in Silk fields (median = 14.26%). Impacts of epidemics on yield ranged from 18.4 to 8192.5 kg ha-1 year-1, with an average of 1856.7 kg ha-1 year-1. The higher economic impact of the disease was observed on Silk cultivar with an average loss of USD 1974.2 ha-1 year-1. Overall, estimated losses increased on average by USD 109.8 ha-1 year-1 at each 1% of incidence. Aggregation of FWB was detected by all analytical methods in 13 fields (1 of Cavendish, 11 of Pome, and 1 of Silk). In the other 17 fields, at least one analytical method did not reject the null hypothesis of randomness. One field (5 ha), composed of six plots, was selected for spatial and temporal studies during two years with bi-monthly assessments. A sigmoidal curve represented the FWB progress and the Gompertz model best-fitted disease progress. The level of aggregation varied over time, and evidence of secondary infection to neighboring and distant plants was detected. FWB is a widespread problem in Brazil and yield losses can be of high magnitude. Epidemiology-based management strategies can now be better established.
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Banana, the main export fruit for Colombia, is threatened by Fusarium wilt (FWB), caused by Fusarium oxysporum f. sp. cubense (Foc), tropical race 4 (TR4). Pathogen containment through disinfecting tools, machinery, shoes, and any means that may carry contaminated soil particles with proper disinfectants is at the forefront of disease management. In this study, the biocide efficacy of 10 commercial quaternary ammonium compounds (QACs) products and one based on glutaraldehyde (GA) were evaluated on both reproductive structures (microconidia and macroconidia) and survival spores (chlamydospores) of Foc TR4 (strain 140038) isolated from La Guajira, Colombia. QACs were evaluated at 1200 ppm and two exposure times: <1 and 15 min in the absence or presence of soil. For GA disinfectant, four different concentrations (500, 800, 1200, and 2000 ppm) were evaluated at both contact times in the presence of soil. In the absence of soil, all QACs showed 100% biocidal efficiency against microconidia, macroconidia, and chlamydospores at both <1 and 15 min. The presence of soil decreased the efficacy of disinfectants, but some of them, such as QAC3_1st, QAC7_4th, and QAC5_4th, showed 98%, 98%, and 100% efficacy against Foc TR4 chlamydospores, respectively, after <1 min of contact time. For instance, the GA-based disinfectant was able to eliminate all Foc TR4 propagules after 15 min for all concentrations tested.
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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.
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Culminating in the 1950's, bananas, the world's most extensive perennial monoculture, suffered one of the most devastating disease epidemics in history. In Latin America and the Caribbean, Fusarium wilt (FW) caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (FOC), forced the abandonment of the Gros Michel-based export banana industry. Comparative microbiome analyses performed between healthy and diseased Gros Michel plants on FW-infested farms in Nicaragua and Costa Rica revealed significant shifts in the gammaproteobacterial microbiome. Although we found substantial differences in the banana microbiome between both countries and a higher impact of FOC on farms in Costa Rica than in Nicaragua, the composition especially in the endophytic microhabitats was similar and the general microbiome response to FW followed similar rules. Gammaproteobacterial diversity and community members were identified as potential health indicators. Healthy plants revealed an increase in potentially plant-beneficial Pseudomonas and Stenotrophomonas, while diseased plants showed a preferential occurrence of Enterobacteriaceae known for their plant-degrading capacity. Significantly higher microbial rhizosphere diversity found in healthy plants could be indicative of pathogen suppression events preventing or minimizing disease expression. This first study examining banana microbiome shifts caused by FW under natural field conditions opens new perspectives for its biological control.