Evaluation de la technique de surgreffage pour le rénouvellement des vieillissants vergers d’anacardier [Anacardium occidentale (L.)] dans la région du Gontougo en Côte d’Ivoire

La Côte d’Ivoire est le premier pays producteur et exportateur mondial de noix de cajou. Toutefois, les rendements en noix des vergers ivoiriens demeurent faibles. Ces faibles rendements sont dus à un parc composé de vergers vieillissants, à l’absence de variétés améliorées et à la forte densité des plantations. L’objectif général de la présente étude est de contribuer au renouvellement du verger anarcardier par la technique de surgreffage. Pour y arriver, les arbres de différents âges et peu productifs ont été recepés à différentes hauteurs, différentes circonférences du tronc et sous différents niveaux d’éclaircie. Trois mois après le recépage, des greffons prélevés sur des arbres élites ont été greffés sur les repousses. Les résultats collectés ont montré que les plus jeunes arbres et les arbres plus âgés ont donné les plus courts délais de repousse (30,52 à 33,38 jours). Le nombre de pousses feuillées, la surface foliaire des feuilles émises et le pourcentage de réussite ont été plus importants lorsque les arbres ont été recépés à une hauteur de 140 cm à partir du sol. L’analyse de variance a permis de faire ressortir la différence entre les individus pour chaque facteur étudié. Les arbres de diamètre supérieur à 50 cm ont produit le plus grand nombre de pousses feuillées (32). Selon le niveau de l’éclaircie, les greffons bien eclairés ont été plus vigoureux. Les poids moyens des arbres surgreffés selon les génotypes ont été compris entre 27,5 et 234 g/arbre contre 493 g/arbre pour les arbres en plantation non surgreffés.Côte d'Ivoire is the world's leading producer and exporter of cashew nuts. However, walnut yields in Ivorian orchards remain low. These low yields are due to a park of aging orchards, lack of improved varieties and high density of plantations. The general objective of this study is to contribute to the renewal of the cashew apple orchard by the technique of over grafting To achieve this, trees of different ages and low productivity were received at different heights, different trunk circumferences and under different levels of thinning. Three months after the grafting, grafts taken from elite trees were grafted on the regrowth. The results collected showed that the youngest trees and older trees gave the shortest regrowth (30.52 to 33.38 days). The number of leafy shoots, the leaf area of the leaves emitted and the percentage of success were greater when the trees were retrieved at a height of 140 cm from the ground. . The analysis of variance made it possible to highlight the difference between the individuals for each factor studied. Trees larger than 50 cm produced the largest number of leafy shoots (32). Depending on the level of thinning, the well-lit gryphon was more vigorous. The average weights of the trees grafted according to the genotypes were between 27.5 and 234 g / tree against 493 g / tree for non-grafted plantation trees

Micro-Hotspots of Risk in Urban Cholera Epidemics.

Targeted interventions have been delivered to neighbors of cholera cases in major epidemic responses globally despite limited evidence for the impact of such targeting. Using data from urban epidemics in Chad and Democratic Republic of the Congo, we estimate the extent of spatiotemporal zones of increased cholera risk around cases. In both cities, we found zones of increased risk of at least 200 meters during the 5 days immediately after case presentation to a clinic. Risk was highest for those living closest to cases and diminished in time and space similarly across settings. These results provide a rational basis for rapidly delivering targeting interventions

A Case of Cyperus spp. and Imperata cylindrica Occurrences on Acrisol of the Dahomey Gap in South Benin as Affected by Soil Characteristics: A Strategy for Soil and Weed Management

Because of the limiting efficacy of common weed control methods on Cyperus spp. and Imperata cylindrica their occurrences in tropical agroecologies and the effect of soil properties in suppressing these species were investigated in south Benin (Cotonou), a typical ecology of the Dahomey gap. Weeds and soil samples were collected twice early and later in the rainy season in 2009 at four topographic positions (summit, upper slope, middle slope, and foot slope). Sampling was done according to Braun-Blanquet abundance indices (3 and 5) and the absence (0) of Cyperus and Imperata in a quadrat, respectively. The relationship between their respective abundances and soil parameters (texture, C, N, P, K, Na, Ca, Mg, and Fe) was explored. Weed occurrence was less related to soil texture, and Imperata growth was more influenced by soil nutrients (K, Ca, and Fe) than Cyperus spp. Soil cation ratios of K : Mg and Ca : Mg were the main factors that could be changed by applying K and/or Mg fertilizers to reduce Cyperus and/or Imperata occurrence. Maintaining high Fe concentration in soil at hillside positions can also reduce Imperata abundance, especially in the Dahomey gap

Mortality Rates during Cholera Epidemic, Haiti, 2010–2011

The 2010 cholera epidemic in Haiti was one of the largest cholera epidemics ever recorded. To estimate the magnitude of the death toll during the first wave of the epidemic, we retrospectively conducted surveys at 4 sites in the northern part of Haiti. Overall, 70,903 participants were included; at all sites, the crude mortality rates (19.1–35.4 deaths/1,000 person-years) were higher than the expected baseline mortality rate for Haiti (9 deaths/1,000 person-years). This finding represents an excess of 3,406 deaths (2.9-fold increase) for the 4.4% of the Haiti population covered by these surveys, suggesting a substantially higher cholera mortality rate than previously reported

Rotavirus Surveillance in Urban and Rural Areas of Niger, April 2010–March 2012

To access this article, click on "Additional Links".Knowledge of rotavirus epidemiology is necessary to make informed decisions about vaccine introduction and to evaluate vaccine impact. During April 2010–March 2012, rotavirus surveillance was conducted among 9,745 children <5 years of age in 14 hospitals/health centers in Niger, where rotavirus vaccine has not been introduced. Study participants had acute watery diarrhea and moderate to severe dehydration, and 20% of the children were enrolled in a nutrition program. Of the 9,745 children, 30.6% were rotavirus positive. Genotyping of a subset of positive samples showed a variety of genotypes during the first year, although G2P[4] predominated. G12 genotypes, including G12P[8], which has emerged as a predominant strain in western Africa, represented >80% of isolates during the second year. Hospitalization and death rates and severe dehydration among rotavirus case-patients did not differ during the 2 years. The emergence of G12P[8] warrants close attention to the characteristics of associated epidemics and possible prevention measures