Search

We present an amended description of the bacterial species Xanthomonas vasicola to include the causative agent of banana Xanthomonas wilt, as well as strains that cause disease on Areca palm, Tripsacum grass, sugarcane, and maize. Genome-sequence data reveal that these strains all share more than 98% average nucleotide with each other and with the type strain. Our analyses and proposals should help to resolve the taxonomic confusion that surrounds some of these pathogens and help to prevent future use of invalid names.

Biodiversity supports sustainable food production, although recognition of its roles has been relatively neglected in the sustainable intensification literature. In the current study, the roles of biodiversity in sustainable food production are considered, assessing how these roles can be measured, the current state of knowledge and opportunities for intervention. The trajectory of global food production, and the challenges and opportunities this presents for the roles of biodiversity in production, are also considered, as well as how biodiversitybased interventions fit within wider considerations for sustainable food systems. The positive interactions between a diverse array of organisms, including annual crops, animal pollinators, trees, micro-organisms, livestock and aquatic animals, support food production globally. To support these interactions, a range of interventions related to access to materials and practices are required. For annual crops, major interventions include breeding crops for more positive crop–crop interactions, and the integration of a wider range of crops into production systems. For animal pollinators, major interventions include the introduction of pollinator populations into production landscapes and the protection and improvement of pollinator habitat. For trees, a major required intervention is the greater integration of perennial legumes into farmland. For micro-organisms, the implementation of agronomic practices that support beneficial crop-microbe interactions is crucial. For livestock production, breed and crop feedstock diversification are essential, and the implementation of improved methods for manure incorporation into cropland. Finally, in the case of aquatic production, it is essential to support the wider adoption of multi-trophic production systems and to diversify crop- and animal-based feed resources. These and other interventions, and the research needs around them, are discussed. Looking to the future, understanding the drivers behind trends in food systems is essential for determining the options for biodiversity in supporting sustainable food production. The increased dominance of a narrow selection of foods globally indicates that efforts to more sustainably produce these foods are crucial. From a biodiversity perspective, this means placing a strong emphasis on breeding for resource use efficiency and adaptation to climate change. It also means challenging the dominance of these foods through focusing on productivity improvements for other crop, livestock and aquaculture species, so that they can compete successfully and find space within production systems. New biodiversity-based models that support food production need not only to be productive but to be profitable. Thus, as well as describing appropriate production system management practices that enhance production and support the environment, the labour, knowledge, time required to operationalize, and other costs of new production approaches, must be considered and minimized. To support the future roles of biodiversity in sustainable food production, we recommend that particular attention be given to the longitudinal analysis of food sectors to determine how the diversity of foods consumed from these sectors has changed over time. Analysis is already available for crops, but related research is needed for livestock and aquaculture sectors. This analysis will then support more optimal cross-sectoral interactions, in terms of the contributions each sector provides to supplying the different components of human diets. Additional meta-analyses and synthetic reviews of case studies are required as an evidence base for biodiversity-based food production system interventions, but future studies should pay more attention to articulating the potential biases in case study compilation (the problem of ‘cherry picking’ positive examples) and the measures that have been taken to minimize such effects.

The genus Musa is not native to Africa. It evolved in tropical Asia, from southwest India eastward to the island of New Guinea. There is a growing circumstantial evidence which suggests that the East African Highland banana and the tropical lowland plantain were cultivated on the African continent since before 1 AD. It is also probable that ABB cooking and AB and AAB dessert cultivars were brought to the continent from India by Arabian traders from 600 AD, and that these were disseminated throughout East Africa. During the colonial era, the main centres of distribution for banana cultivars were botanical gardens, such as Zomba in Malawi, Entebbe in Uganda and Amani in Tanzania. It appears that the very early introductions of Highland banana and plantain arrived in Africa as a relatively clean material without the conspicuous pests and diseases that affect them in Asia. In contrast, several devastating problems now impact the crop in Africa, including nematodes, the borer weevil and diseases, most notably banana bunchy top, banana streak, Sigatoka leaf spots, Xanthomonas wilt and Fusarium wilt. We (a) provide chronological overviews of the first reports/observations of different Musa pests and pathogens/diseases in Africa, (b) highlight specific examples of when a pest or pathogen/disease was introduced via planting materials and (c) give recent examples of how the pests and pathogens spread to new regions via planting materials. In total, these production constraints threaten banana and plantain production throughout the continent and impact those who can ill afford lost production, the small-holder producer. Our intent in this review is to highlight the significance of these problems and the great importance that infested planting materials have played in their development.

Bananas are not native to Africa. They evolved in tropical Asia, from Southwest India eastward to New Guinea. There is growing circumstantial evidence which suggests that the East African Highland banana (EAHB) and the tropical lowland plantain were cultivated on the African continent since before AD ^. It is likely that Arabian traders (from 600 AD) brought ABB, AB and dessert AAB bananas from India to the continent and that these were slowly diffused in East Africa. The main centres of diffusion, for bananas introduced in colonial times, were botanical gardens (e.g. Zanzibar, Zomba in Malawi, Entebbe in Uganda and Amani in Tanzania). It appears that the very early introductions of EAHB and plantain arrived in Africa without many of the major pests and pathogens affecting them in Asia, at least those that cause conspicuous damage and for which recent records on the continent exist. A wide range of Musa pests (nematodes and weevils) and diseases (banana bunchy top, banana streak, fungal leaf spot diseases, Xanthomonas wilt and Fusarium wilt) currently threaten banana/plantain cultivation across the African continent with severe implications for smallscale banana farmers. Examples of introductions with planting material are numerous, highlighting the need to implement strict quarantine measures. For example, the first reports of Fusarium wilt in East Africa were apparently associated with workers returning to the region from Mauritius after World War II. In addition, the banana weevil was most likely introduced in Uganda around 1908 with imported banana plants, which had been established in the Botanic Gardens at Entebbe. This paper (i) gives a chronological overview of first reported observations of a Musa pest or disease in Africa; (ii) highlights specific examples where a pest or disease was introduced with planting materials; and (iii) gives recent examples of how a pest or disease spread to a new region though infested or infected planting materials.

L'INIBAP vient de publier la deuxième édition de Musalogue, un catalogue sur la diversité des #Musacées#. Cette publication contient des descriptions et des photos des différentes espèces et variétés, couvrant l'essentiel de la diversité présente au sein de ce genre. Chaque entrée du catalogue est accompagnée d'une photo et d'une description morphotaxonomique de la plante telle qu'elle peut être observée sur le terrain. Cette publication repose sur les informations que les responsables des collections de matériel génétique de Guadeloupe, du Cameroun, d'Australie et d'Ouganda ont fournies à l'INIBAP au travers du Système d'information sur les ressources génétiques des Musacées (MGIS). Le catalogue est divisé en deux parties : La première partie est consacrée aux espèces sauvages : #Australimusa#, #Callimusa#, #Eumusa# et #Rhodochlamys#. La seconde donne des informations sur les variétés cultivées : #Eumusa acuminata#, #Eumusa acuminata# x #balbisiana#, #Eumusa acuminata# x #schizocarpa#, #Australimusa#, #Eumusa# x #Eustralimusa#