Caractérisation physico-chimique de l’eau des noix matures de nouveaux hybrides améliorés de cocotiers (Cocos nucifera L.) grands

Des hybrides améliorés de cocotiers grands ont été créés par la Station de recherche Marc Delorme en vue de satisfaire les préférences des grosses noix des acteurs de la filière cocotier. Cependant ils demeurent encore peu étudiés. Le présent travail évalue les caractéristiques physicochimiques de l’eau des noix matures de ces nouveaux hybrides en vue d’en proposer des voies de valorisation. Les travaux portent sur des noix âgées de treize mois (rang 25) d’hybrides de cocotiers grands GPY+ x GOA+, GPY+ x GRL+ et GRL+ x GOA+ en comparaison avec l’hybride PB121+, pris comme témoin. La masse des noix entières et de l’eau de coco ont été déterminés moins de 24 h après la récolte des noix de coco. Puis des échantillons d’eau de coco ont été prélevés et conservés à -15 °C avant leurs caractérisations. Les résultats ont montré que l’eau de coco mature est plus abondante et plus acide chez les hybrides améliorés de cocotiers grands que chez le PB121+. Parmi les trois hybrides grands améliorés, GRL+ x GOA+ fournit l’eau de coco mature la plus pourvue en cendres (0,49%). Les hybrides GPY+ x GOA+ et GPY+ x GRL+ renferment plus de sucres (29,37 et 28,09 mg/ml) et de polyphénols (58,11 et 65,49 ppm). Il ressort de ces études que l’eau des noix matures de ces hybrides pourrait être utilisée pour la production d’alcool éthylique et de vinaigre.Mots clés : Valorisation, eau de coco, caractéristiques, vinaigre, alcool, Côte d’Ivoir

Laboratory study of the biology and behaviour of Diplonychus sp (Belostomatidae) and its vector competence in the transmission to humans of Mycobacterium ulcerans, the pathogen causing Buruli ulcer in Côte d’Ivoire (West Africa).

Buruli ulcer is a skin infection caused by a mycobacterium occurring in the environment, Mycobacterium ulcerans.  Ranked third in terms of number of mycobacterial infections after leprosy and tuberculosis, its epidemiology is the most poorly understood of the three. Humans are infected through the skin while performing daily living activities (e.g. rice cultivation, fish farming, fishing, laundry, fetching water, agricultural work) or leisure activities (e.g. bathing) in endemic areas. The disease is particularly prevalent in West Africa, where the number of cases is increasing annually (2442 cases in 2008). Côte d’Ivoire is the most severely affected country in the world with more than 25 000 cases since 1978. The numerous endemic foci for Buruli ulcer are scattered throughout the country. Over the past four years impressive progress has been made in researching the mode of transmission of M. ulcerans infection. Yet despite this, many questions remain unanswered. In Central and West Africa aquatic insects of the order Hemiptera appear to be involved in the transmission of Buruli ulcer.  It is likely that aquatic Hemiptera play a role.  Studies of the salivary glands of insects that have been experimentally infected and allowed to bite white mice demonstrate the probable role of water bugs as hosts or possible vectors of M. ulcerans. In addition, at least 10% of environmental biological specimens tested positive using PCR in Cameroon and Côte d’Ivoire. These pterygot insects are also able to fly from one body of water to another over varying distances, attracted by lights in houses near marshy areas. This method of displacement could account for the current progression of the disease in West Africa and particularly in Côte d’Ivoire, where it is spreading northwards from the south, west, east and centre of the country.   Buruli ulcer is not a contagious disease.  It is, however, terrifying and severely disabling.  Patients must spend long periods in hospital, treatment is costly and burdensome, and can lead to social marginalization or even total exclusion; above all, the mode of transmission is still poorly understood.  Local people must therefore be familiarized with preventive measures focusing on identification of the probable vectors of the disease in order to break the chain of transmission of M. ulcerans. This presupposes a sound knowledge of the biology, ecology and behaviour of these potential vectors. Accordingly, we have proceeded to laboratory farm the bug most commonly encountered in the environment that shows the highest rates of infection by M. ulcerans (more than 10%), namely Diplonychus sp of the family Belostomatidae. Adult specimens were collected in the vicinity of fishponds at an experimental station situated between Abidjan and Dabou (a non-endemic site) and subsequently farmed in the laboratory at the Côte d’Ivoire National Institute of Public Health. The parameters used to farm this water bug were standardized in the laboratory (water quality, depth, turbidity, pH, temperature, luminosity, suitable vegetable environment). The insects were fed regularly with mosquito larvae. The embryonic lifespan, the hatching time, the larval period and the number of larval stages prior to adulthood were studied. The adult lifespan was also estimated. Five successive generations of Diplonychus sp were obtained. From egg to adulthood, the larval lifespan is 41 days on average, with deviations from the mean of 29 to 54 days.  Hatching generally took place 7 days after egg laying.  Five larval stages are distinguishable, separated by five metamorphoses.  The lifespan of certain adults obtained in the laboratory varied between 16 and 150 days.  The last original parental specimens survived for 11 months.  Proficiency in the laboratory farming of Diplonychus sp could enable us to decode its genome and collect saliva samples, while also allowing us to perform experimental infections using human strains of M. ulcerans in order to confirm or rule out the involvement of this insect in the transmission of Buruli ulcer in Central and West Africa

Thonides debarques par les pecheurs artisans dans la zone d’abidjan (Cote d’Ivoire) source potentielle d’une amelioration de la securite alimentaire

Dans le cadre des activités de suivi de la pêche artisanale maritime, une étude sur la production des thonidés débarqués a été réalisée. Elle avait pour but d’obtenir les informations indispensables à une estimation de la capture nationale de thonidés, à l’égard de la problématique de la sécuritéalimentaire. La méthodologie utilisée a consisté à collecter les données chaque jour par des techniciens des structures de recherches de 2014 à 2017, sur les sites de débarquements d’abobodoumé, de zimbabwé et du port. Les résultats obtenus indiquent une similarité dans les productions de 2014 à 2016 avec une augmentation en importante en 2017 due à l’intérêt que suscite la pêche des thonidés chez les pêcheurs. Compte tenu des prises importantes de ces espèces de poisson, une organisation rigoureuse des activités pourrait militer davantage en faveur des moyens et stratégies à mettre en oeuvre pour assurer le renforcement de la sécurité alimentaire dans ce sous-secteur de la pêche.Mots clés : Thonidés, Pêcheurs artisans, Production, Sécurité alimentaire, Côte d’Ivoire

Caractéristiques gustatives de l’eau des fruits de quatre cultivars du cocotier (Cocos nucifera L.)

Les caractéristiques gustatives (descriptives et hédoniques) de l’eau des fruits de quatre cultivars du cocotier (Cocos nucifera L.) ont été étudiées au cours de la maturation des noix. Il s’est agi du Grand OuestAfricain, du Nain Jaune de Malaisie, du Nain Vert de Guinée Equatoriale et de l’hybride PB121 amélioré. Les paramètres testés ont été les saveurs (sucrée, salée et acide) et les préférences gustatives. Les résultats obtenus ont montré des interactions significatives entre les cultivars et les stades de maturité pour les paramètres analysés. Ainsi, au cours de la maturation des noix, la saveur sucrée de l’eau de coco est prédominante quel que soit le stade de maturité. Elle est maximale chez les cultivars nains de rang 21 avec des perceptions équivalant à des teneurs en sucres de 5,80 à 6,10%. A maturité, la saveur sucrée de l’eau de coco baisse car les sucres interviennent dans la formation de l’amande. Les résultats des tests hédoniques ont abouti à la préférence de l’eau de coco en fonction de son goût sucré. Ainsi, l’eau des noix immatures des cultivars nains a été la plus appréciée. Cette étude a permis de déterminer les caractéristiques sensorielles de l’eau de coco afin de fournir des indicateurs pour une valorisation technologique efficiente.Mots clés: Eau de coco, tests sensoriels, cultivars, maturation

Agromorphological characterization of three (3) hybrid carrot varieties (Daucus carota), cultivated in the commune of Korhogo, in northern Côte d'Ivoire

The carrot (Daucus carota) is a biennial plant whose pivoting root plays a major role in feeding populations worldwide. Few studies have been carried out on the characterization of the agromorphological diversity of this species. Varieties were collected, in order to assess their agromorphological performances under the ecological conditions of Korhogo. The Amazonia, Pamela+, Bahia and Madona varieties were evaluated. The Amazonia variety, which is the most cultivated in the Korhogo region, was used as a control. The study was carried out using a completely randomized Fisher block system, comprising 4 treatments and 4 repetitions. The blocks were separated by a distance of 80 cm. In the same block, the elementary plots were spaced 50 cm apart. Each elementary plot consists of 6 seeding lines, spaced 25 cm, and comprising 72 plants. The measurements concerned some vegetative and agronomic characteristics. The results obtained showed that the Pamela+ variety, with a yield of 25 t/ha, was the most productive. It is also distinguished from other varieties by the length of the roots and the high number of leaves produced. The Bahia and Madona varieties showed similar characteristics and less efficient than those of the control (Amazonia). On the basis of the characteristics evaluated, the Pamela+ variety was the most efficient and adapted to the agroecological conditions of the Korhogo region. However, the evaluation of certain characteristics will confirm the results of this study

'Candidatus phytoplasma palmicola’: a novel taxon associated with a lethal yellowing-type disease (LYD) of coconut ( Cocos nucifera L.) in Mozambique

In this study, the taxonomic position and group classification of the phytoplasma associated with a lethal yellowing-type disease (LYD) of coconut (Cocos nucifera L.) in Mozambique were addressed. Pairwise sequence similarity values based on alignment of near full-length 16SrRNA genes (1530 bp) revealed that the Mozambique coconut phytoplasma (LYDM) shared 100% identity with a comparable sequence derived from a phytoplasma strain (LDN), responsible for Awka wilt disease of coconut in Nigeria, and shared 99-99.6% identity with 16S rRNA sequences from strains associated with Cape St. Paul wilt (CSPW) disease of coconut in Ghana and Côte d'Ivoire. Similarity scores further determined the 16S rRNA gene of LYDM phytoplasma to share <97.5% sequence identity with all prior descriptions of ‘Ca. Phytoplasma’ species. Presence of unique regions in the 16S rRNA distinguished LYDM phytoplasma from all currently described ‘Candidatus Phytoplasma’ species, justifying its recognition as reference strain of a novel taxon, ‘Candidatus Phytoplasma palmicola’. Restriction fragment length polymorphism (RFLP) profiles of the F2n/R2 portion (1251 bp) of the 16S rRNA gene and pattern similarity coefficient values delineated coconut LYDM phytoplasma strains from Mozambique as new members of established group 16SrXXII, subgroup A (16SrXXII-A). Similarity coefficients of 0.97 were obtained for comparisons between subgroup 16SrXXII-A strains and CSPW phytoplasmas from Ghana and Côte d'Ivoire. On this basis, CSPW phytoplasma strains were designated as members of a new subgroup, 16SrXXII-B

Décomposition des tourteaux de coprah et de palmiste et effets sur la croissance des cocotiers (Cocos nucifera L.) en pépinière et la nutrition minérale des cocotiers adultes en Côte-d\'Ivoire

L\'objectif de cette étude est d\'évaluer le potentiel fertilisant des tourteaux de coprah et de palmiste. Ainsi, les tourteaux ont été mis en décomposition pendant une période de 12 mois. Leurs effets sur la croissance des jeunes cocotiers ont été étudiés pendant 9 mois en comparaison à ceux de l\'engrais chimique. Une analyse foliaire a été réalisée afin d\'évaluer les effets des tourteaux sur la nutrition minérale des cocotiers adultes, 7 et 21 mois après leur épandage. Après 12 mois, les tourteaux ont libéré la totalité du potassium et plus de la moitié de l\'azote et du phosphore. Ils ont eu un effet positif sur la croissance des cocotiers en pépinière semblable à celui de la fumure chimique composée d\'urée à 46 % de N, super phosphate simple à 18 % de P2O5, chlorure de potassium à 60 % de K2O et de kiesérite à 28 % de MgO. Sept mois après l\'épandage, ils ont amélioré les teneurs foliaires en azote, en phosphore et en potassium des cocotiers adultes, mais ces teneurs ont chuté 21 mois après. Ces résultats montrent que les tourteaux sont des engrais organiques qui pourraient remplacer la fumure chimique.The objective of this study is to assess the fertilizing potential of the oil-cakes of copra and palm tree. Thus, the oilcakes were allowed to decompose for 12 months period. Their effects on the growth of young coconuts were studied for 9 months in comparison with those of chemical fertilisers. A foliar analysis was carried out in order to assess the effects of the oil-cakes on the mineral nutrition of adult coconuts 7 and 21 month after application. After 12 months, the oil-cakes released the totality of the potassium and more than half of nitrogen and phosphorus. Application of oil-cakes had a positive effect on the growth of coconuts in nursery similar to the one of the chemical fertilizer, consisted of urea (46 % of N), super simple phosphorus (18 % of P2O5), potassium chloride (60 % of K2O) and kieserite (28 % of MgO). Seven months after application, they improved the foliar contents of nitrogen, phosphorus and potassium of adult coconuts, but these contents fell 21 month later. These results show that the oil-cakes may be used as organic fertilizers that could replace the chemical fertilizers. Keywords: Coconut, nitrogen, potassium, mineral nutrition, phosphorus, oil-cakes.Sciences & Nature Vol. 5 (2) 2008: pp. 155-16

Lippia multiflora (verbenaceae) en Côte d’Ivoire : point des premiers resultats de recherche et Enjeu cultural

Lippia multiflora (Verbenaceae) ou thé de savane pousse naturellement dans les régions de savane en Côte d’Ivoire. Dans le cadre de la diversification des cultures en Côte d’Ivoire, des recherches récentes ont été conduites en vue de la caractérisation de sa composition, sa domestication et sa valorisation, ont abouti à des résultats. Des résultats de recherche couvrant les années 1996 à 2009 de travaux sur Lippia multiflora ont concerné cette analyse. Ceux-ci concernent différents champs disciplinaires dont des évaluationspédologiques, agrophysiologiques, physicochimiques et médicinales effectués en Côte d’Ivoire. Les particularités de cette plante en interaction avec les paramètres environnementaux de sa culture mises en valeur sont discutées

Macroinvertebrate Communities Associated with Hydrilla verticillata (Royle, 1839) and Relationship with Environmental Factors in Ono Lagoon, Southeast of Côte d’Ivoire

The macroinvertebrates associated with Hydrilla verticillata was studied in Ono lagoon, South-eastern of Côte d'Ivoire. Monthly samples of macrophytes with their associated macroinvertebrates were collected in upstream, centre and downstreamusing a Van veen grab of 0.314 m2 internal area. The environmental variables (temperature, transparency, depth, conductivity, TDS, pH, dissolved oxygen, , , and ) were also recorded. A total of 71 taxa belonging to 28 families, 11 orders, 05 classes and 03 phyla of which 40 taxa were recorded in upstream, 45 taxa in centre and 44 taxa in downstream. Insects numerically dominated the capture, comprising 91.55% of the collectedtaxa with Odonata and Coleoptera being the most diverse and abundant groups. The density was higher in upstream (1407ind. per 100 g d.w.) and lower in downstream (1062 ind. per 100 g d.w.), whist theLibellulidae and Corduliidae exhibited the highest density communities. The rarefied richness did not show spatial variation but vary significantly between seasons. The Evenness did not show spatial and seasonal variations. However, Shannon diversity index varied significantly between sites and seasons. From the results of RDA analysis, conductivity and pH showed a strong environmental gradient and had a structuring effect on macroinvertebrate communities