Risks of new pests and diseases

Climate change will affect the social and environmental determinants of the health of human, animal and plant populations around the world. It will challenge the social and biological capacities of food systems to regulate the emergence of pests and pathogens. Especially in Low-Income (LI) and Lower Middle-Income (LMI) countries, food systems will be dealing with new pests, diseases and emerging pathogens (viruses, bacteria, mycoplasma and fungi) severely threatening the health of vulnerable people and potentially exacerbating social and economic inequalities

Travaux en biométrie au Cocoa and Coconut Research Institute : mission en Papouasie Nouvelle-Guinée du 26 octobre au 5 novembre 2000

Un appui en biométrie a été apporté aux chercheurs du CCRI (Cocoa & Coconut Research Institute) de la station de Tavilo. Cette mission, financée par le M.A.E. (Ministère français des affaires étrangères), a permis une valorisation des données issues de plusieurs recherches menées au CCRI. Une coopération plus active entre le CCRI et le CIRAD-CP dans le domaine de la biométrie et de l'exploitation statistique des essais serait utile. Des données issues des recherches conduites par les chercheurs du CCRI ont été analysées; elles concernent principalement des expérimentations réalisées en phytopathologie et sélection du cacaoyer. De nombreuses données restent encore à saisir et à exploiter. Il parait important de mettre en place un suivi rapproché en biométrie afin de former les chercheurs à l'analyse de leurs données pour une meilleure valorisation des résultats. (Résumé d'auteur

Fruit trait variation in a caribbean germplasm collection of aromatic hot peppers (Capsicum chinense Jacq.)

Aromatic hot peppers (Capsicum chinense Jacq.) are an important agricultural commodity for many small-scale farmers in the Caribbean because it is a commercially viable crop and one that is integral to the cuisines of the region. The large variation in fruit shape, size, color, pungency, and aroma of this species facilitates a diverse range of uses. Using 264 accessions from a Caribbean germplasm collection (representing primarily the Caribbean Basin, Central and South America), this study investigated 1) morphological variation in 13 fruit descriptors of agro-economic importance; and 2) morphological groups based on geographic origin. All 13 fruit descriptors showed significant variation. Fruit color [immature (six states) and mature (12 states)] was the most diverse qualitative fruit trait. Among the quantitative traits, fruit weight and fruit width showed the highest broad-sense heritability (0.81), and fruit weight was highly correlated with fruit width and placenta size. Cluster analysis revealed four main clusters, which did not show a clear separation of accessions based on major geographic regions, but there was a highly significant association (P < 0.0001) between geographic subgroups and the clusters to which they were assigned. Most accessions of the Northern Caribbean (particularly the Bahamas and Puerto Rico) separated quite distinctly from most accessions of the Southern Caribbean and clustered with most accessions of Central and South America. Accessions of the Southern Caribbean (Lesser Antilles, Trinidad & Tobago) were substantially more similar to each other than they were to most accessions of Central and South America, thereby suggesting genetic differences between accessions of the Southern Caribbean islands and the mainland populations. Collectively, the results show that this germplasm collection contains useful accessions with desired fruit quality traits and a level of genetic variation that can be used to encourage its active conservation and use for further evaluation trials and crop improvement as well as guide ongoing complementary germplasm introductions to augment the collection's diversity. (Résumé d'auteur

Brocap trap to control the coffee berry borer in Indonesia

The coffee berry borer (CBB, Hypothenemus hampei Ferr.) is the most serious insect pest on coffee in Indonesia. It causes significant yield losses in terms of coffee production, but also reduces coffee bean quality, resulting in low productivity and the poor quality of Indonesian coffee. On average, CBB infestation on Indonesian coffee is more than 20%, and it results in yield losses of more than 10%. Using traps is the new CBB control method and the Brocap trap, developed by CIRAD and PROCAFE in El Salvador, is specially designed for Hypothenemus hampei. The trap is considered as a useful addition to IPM for CBB control in Indonesia. (Résumé d'auteur

Etude génétique de la granulométrie des fèves de cacaoyer (Theobroma cacao L.) : relation avec des caractères agronomiques

La granulométrie des fèves de cacaoyer est étudiée dans un essai diallèle 6 x 6, installé au sud-ouest du Cameroun. Les taux de cabosses affectées par la pourriture brune et la production réelle permettent une analyse des corrélations avec la taille des fèves. L'aptitude générale à la combinaison constitue la principale source de variation de la granulométrie et ce caractère présente une grande héritabilité. La corrélation génétique d'additivité positive entre la granulométrie et le taux de cabosses pourries implique que les transmissions de ces caractères sont génétiquement liées. Dans les sélections en cours pour la résistance à la pourriture brune des cabosses, la granulométrie doit être étudiée, afin d'éviter une baisse de la taille des fèves. Une sélection sur index est recommandée pour maintenir la granulométrie et augmenter les niveaux de résistance. (Résumé d'auteur

Climate change in tropical environment: what impact on agricultural pests and diseases? What crop protection strategies? [P161]

Global travel, world trade and change in climate conditions increase the risks from pest and disease incursions and outbreaks in many agricultural systems, threatening food security. Because insects are poikilothermic organisms they are able to change their habits and status, extend their distribution and as a consequence create more crop damage and economic losses. In this context farmers and crop protection specialists are concerned, particularly in temperate regions where the impact of climate change is obvious and well described. For example in Europe, the list of newly introduced insects, diseases and weeds coming from the south is increasing every year. In the tropical world, the impact of climate change on pest and disease populations and their natural enemies is less obvious and more difficult to apprehend. Through different examples of tropical agrosystems, this paper shows the effect of climate change on some major pests and diseases such as the coffee leaf rust, the coffee berry borer, the sugarcane stemborers, the cotton bollworm, and discusses new crop protection solutions to cope with the situation of climate change. On the one hand, these solutions are based on biosecurity plans to prevent any new introduction, and on the other hand they are based on agroecological management, with a particular emphasis on conservation of natural enemies to increase biocontrol and minimize pest infestation and outbreaks. (Texte intégral

Plant and fruit trait variations among four Capsicum species in a Caribbean germplasm collection

Despite Capsicum's importance in the Caribbean, comprehensive diversity studies of this species in the region are limited, especially regarding its morphological variation. This study evaluated 37 traits (seedling, vegetative and reproductive) in 201 accessions among four Capsicum species. Multivariate analyses revealed that (i) 54% of the quantitative (seedling and fruit) variation and (ii) 64% of the qualitative (floral and fruit) variation were explained by the first two components. The three main clusters identified did not immediately highlight geographic and species-specific separation. However, significance testing revealed some separation based on geographic subgroups and species assignment. Most Southern Caribbean accessions were considerably similar to each other (if not identical in some cases), thus providing opportunity to identify and remove duplicates from the collection. These Southern Caribbean accessions shared their greatest similarity with Upper Amazon accessions, and least similarity with Lower Amazon accessions, suggesting movement of material primarily from the Upper Amazon into the Southern Caribbean Basin. The dominant differentiating traits displayed in these Southern Caribbean accessions are probably due to strong active selection for certain morphotypes and not to founder effects. Upper and Lower Amazon accessions were largely well differentiated from each other, highlighting key underlying genetic differences between these two populations and possible ongoing barriers to germplasm exchange. Central American, Greater Antilles/Bahamas and Guiana Shield accessions shared similarities with both the Upper and Lower Amazon populations, hinting at probable introductions from both Amazon regions. Collectively, this provides essential baseline information on the morphological (and underlying genetic) relationships among these accessions to guide future characterisation and evaluation efforts on this collection. (Résumé d'auteur