"Green havoc": Panama disease, environmental change, and labor process in the Central American banana industry

The Vulnerability of Cuban Banana Production to Fusarium Wilt Caused by Tropical Race 4

Bananas are major agricultural commodities in Cuba. One of the main constraints of banana production worldwide is Fusarium wilt of banana. Recent outbreaks in Colombia, Perú, and Venezuela have raised widespread concern in Latin America due to the potential devastating impact on the sustainability of banana production, food security, and livelihoods of millions of people in the region. Here, we phenotyped 18 important Cuban banana and plantain varieties with two Fusarium strains-Tropical Race 4 (TR4) and Race 1-under greenhouse conditions. These varieties represent 72.8% of the national banana acreage in Cuba and are also widely distributed in Latin America and the Caribbean region. A broad range of disease responses from resistant to very susceptible was observed against Race 1. On the contrary, not a single banana variety was resistant to TR4. These results underscore that TR4 potentially threatens nearly 56% of the contemporary Cuban banana production area, which is planted with susceptible and very susceptible varieties, and call for a preemptive evaluation of new varieties obtained in the national breeding program and the strengthening of quarantine measures to prevent the introduction of TR4 into the country.

Description of seven new species of Edessa Fabricius, 1803 from Central America (Heteroptera, Pentatomidae, Edessinae)

Not much is known about the Central American stink bug fauna of the Edessinae subfamily. A recent survey of Costa Rican species from this subfamily listed 65 species, of which 47 were new additions. More recently, a description of a group of species of Edessa added more three species to the fauna of Costa Rica. This work is part of a series of articles aiming to review Edessinae from Central America. In this article seven new species are described from Panama and Costa Rica: Edessa bituberculata sp. n., E. bivenulata sp. n., E. enargocelida sp. n., E. fuscolimbata sp. n., E. fuscopunctata sp. n., E. helvoalata sp. n. and E. holochlorata sp. n.

Induced resistance to Fusarium wilt of banana caused by Tropical Race 4 in Cavendish cv Grand Naine bananas after challenging with avirulent Fusarium spp

In the last century, Fusarium wilt of banana (FWB) destroyed the banana cultivar Gros Michel. The Cavendish cultivars saved the global banana industry, and currently they dominate global production (~50%) and the export trade (~95%). However, a new strain called Tropical Race 4 (TR4) surfaced in the late 1960’s, spread globally and greatly damages Cavendish plantations as well as manifold local varieties that are primarily grown by small holders. Presently, there is no commercially available replacement for Cavendish and hence control strategies must be developed and implemented to manage FWB. Here, we studied whether it is possible to induce resistance to TR4 by pre-inoculations with different Fusarium spp. Only pre-treatments with an avirulent Race 1 strain significantly reduced disease development of TR4 in a Cavendish genotype and this effect was stable at various nutritional and pH conditions. We then used transcriptome analysis to study the molecular basis of this response. Several genes involved in plant defence responses were up-regulated during the initial stages of individual infections with TR4 and Race 1, as well as in combined treatments. In addition, a number of genes in the ethylene and jasmonate response pathways as well as several gibberellin synthesis associated genes were induced. We observed upregulation of RGA2 like genes in all treatments. Hence, RGA2 could be a key factor involved in both R1 and TR4 resistance. The data support the hypothesis that activating resistance to Race 1 in Cavendish bananas affects TR4 development and provide a first insight of gene expression during the interaction between various Fusarium spp. and banana.

Genetic diversity and disease: The past, present, and future of an old idea

Why do infectious diseases erupt in some host populations and not others? This question has spawned independent fields of research in evolution, ecology, public health, agriculture, and conservation. In the search for environmental and genetic factors that predict variation in parasitism, one hypothesis stands out for its generality and longevity: genetically homogeneous host populations are more likely to experience severe parasitism than genetically diverse populations. In this perspective piece, I draw on overlapping ideas from evolutionary biology, agriculture, and conservation to capture the far-reaching implications of the link between genetic diversity and disease. I first summarize the development of this hypothesis and the results of experimental tests. Given the convincing support for the protective effect of genetic diversity, I then address the following questions: (1) Where has this idea been put to use, in a basic and applied sense, and how can we better use genetic diversity to limit disease spread? (2) What new hypotheses does the established disease-diversity relationship compel us to test? I conclude that monitoring, preserving, and augmenting genetic diversity is one of our most promising evolutionarily informed strategies for buffering wild, domesticated, and human populations against future outbreaks.

The Vulnerability of Bananas to Globally Emerging Disease Threats

Banana cultivation has increased significantly over the last century to meet the growing demand for this popular fruit. Originating in Southeast Asia, bananas are now produced in >135 different countries in tropical and subtropical regions of the world. Most of this expansion of production is based on a single banana variety, Cavendish, which makes up almost all the export trade grown in large-scale monocultures and a large part of the local trade and represents >40% of all bananas grown globally. Over the last century several major diseases of the banana have emerged and widely expanded their geographic ranges. Cultivars within the Cavendish variety are highly susceptible to these diseases, including yellow Sigatoka, black leaf streak, Eumusae leaf spot, freckle, Fusarium wilt tropical race 4, banana bunchy top, and the bacterial wilts Moko, Xanthomonas wilt, and banana Blood disease. This review graphically illustrates the emergence and rapid intercontinental spread of these diseases and discusses several major disease epidemics in bananas. Evidently, the large-scale monoculture based on the single variety Cavendish has resulted in an extreme level of genetic vulnerability. The resistance to diversification in the Cavendish production chain and the lack of investment in genetics and plant breeding in the recent past means that currently limited genetic solutions are available to replace the Cavendish banana with a set of market acceptable resistant varieties from a range of different genetic backgrounds.

Social-ecological memory and responses to biodiversity change in a Bribri Community of Costa Rica

Social-ecological memory (SEM) is an analytical construct used to consider the ways by which people can draw upon biological materials and social memory to reorganize following a disturbance. Since its introduction into the literature, there have been few cases that have considered its use. We use ethnographic methods to study Bribri people's commercial crops that have been invaded by different fungal pathogens and have undergone several disturbance recovery cycles. We show how the Bribri have used social memory and ecological memory together, dynamic interactions of legacies and reservoirs, and the role of mobile links for reorganization following the impact of fungal diseases. Insights from the Bribri indicate that protection of biodiversity, management practices, and adoption of new species and varieties are all crucial. The SEM concept extends the understanding of Indigenous knowledge, to include linkages to other peoples' memory and to landscapes as reservoirs of SEM. An understanding of how people use SEM to respond to disturbances is necessary as biodiversity changes are expected to become more pronounced in the future.

Health, environment and colonial legacies: Situating the science of pesticides, bananas and bodies in Ecuador

Pesticide-related health impacts in Ecuador's banana industry illustrate the need to understand science's social production in the context of major North-South inequities. This paper explores colonialism's ongoing context-specific relationships to science, and what these imply for population health inquiry and praxis. Themes in postcolonial science and technology studies and critical Latin American scholarship guide this exploration, oriented around an ethnographic case study of bananas, pesticides and health in Ecuador. The challenge of explaining these impacts prompts us to explore discursive and contextual dynamics of pesticide toxicology and phytopathology, two disciplines integral to understanding pesticide-health linkages. The evolution of banana phytopathology reflects patterns of banana production and plant science in settings made accessible to scientists by European colonialism and American military interventions. Similarly, American foreign policy in Cold War-era Latin America created conditions for widespread pesticide exposures and accompanying health science research. Neocolonial representations of the global South interacted with these material realities in fostering generation of scientific knowledge. Implications for health praxis include troubling celebratory portrayals of global interconnectedness in the field of global health, motivating critical political economy and radical community-based approaches in their place. Another implication is a challenge to conciliatory corporate engagement approaches in health research, given banana production's symbiosis of scientifically 'productive' military and corporate initiatives. Similarly, the origins and evolution of toxicology should promote humility and precautionary approaches in addressing environmental injustices such as pesticide toxicity, given the role of corporate actors in promoting systematic underestimation of risk to vulnerable populations. Perhaps most unsettlingly, the very structures and processes that drive health inequities in Ecuador's banana industry simultaneously shape production of knowledge about those inequities. Public health scholars should thus move beyond simply carrying out more, or better, studies, and pursue the structural changes needed to redress historical and ongoing injustices.

Mechanisms Involved in Nematode Control by Endophytic Fungi

Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood but most likely multifactorial. This knowledge gap obstructs the progress regarding the development of endophytes or endophyte-derived constituents into biocontrol agents. In part, this may be caused by the fact that endophytic fungi form a rather heterogeneous group. By combining the knowledge of the currently characterized antagonistic endophytic fungi and their effects on nematode behavior and biology with the knowledge of microbial competition and induced plant defenses, the various mechanisms by which this nematode antagonism operates or may operate are discussed. Now that new technologies are becoming available and more accessible, the currently unresolved mechanisms can be studied in greater detail than ever before.