Phenotypic and Pathogenic Characterization of Leaf Fungi of Yam (Dioscorea spp) Varieties Grown In Côte D’Ivoire

Yam (Dioscorea spp) occupies an important place in the diet of the populations of Côte d’Ivoire. It is a real source of starch and therefore generates enormous commercial potential. However, the decrease in production due to pest attacks represents a real threat to this crop. This study was conducted with the aim of improving yam production in Côte d’Ivoire. To do so, isolations carried out on yam leaves showing symptoms of foliar diseases have allowed us to identify 9 fungal genera. These were Colletotrichum sp., Fusarium sp., Pestalotiopsis sp., Pestalotia sp., Botryodiplodia sp., Aspergillus sp., Mucor sp., Curvularia sp. and Phytophtora sp. Among these fungi, the genus Colletotrichum sp. was the most isolated with a rate of 56% followed by the Fusarium and Pestalotia genera (8%). Pathogenicity tests performed on healthy leaves of two yam varieties revealed that the Dioscorea alata is more susceptible to fungi compared to Dioscorea rotundata. The largest average diameter of necrosis was caused by Pestalotiopsis sp. (5.97 cm) on the Dioscorea alata variety while the smallest was caused by Colletotrichum sp.9 on Dioscorea rotundata (0.5 cm). Combatting these fungi need to be developed for effective management of leaf diseases of yam in Côte d’Ivoire

EFFETS DU LIT ET DE LA DENSITÉ DE PLANTATION SUR LA CROISSANCE VÉGÉTATIVE DE L’ANANAS (ANANAS COMOSUS L., VAR. MD2) DANS LA LOCALITÉ DE DABOU EN CÔTE D’IVOIRE

The aim of this study was to identify the best planting bed and density for vegetative growth of Ananas comosus L. var. MD2 plants in the locality of Dabou in Côte d’Ivoire. The effects of three planting beds : flat land, ridge without polyethylene film and ridge covered with polyethylene film ; and two planting densities : 50,000 and 70,000 plants/ha (D50 and D70, respectively) were tested through a split-plot disposition. At the end of the vegetative phase of the cycle, growth parameters were evaluated. The results showed that D70, average heights apical bunches were higher (91.52 cm) than D50 (86.87 cm). The number of fresh leaves varied between 48 and 51. The ridge covered with polyethylene film was distinguished with a number of relatively larger fresh leaves. The follow-up of the D leaves biomass revealed that seven months, the value of 70 g required to trigger floral induction therapy (FIT) had been reached in all plants, whatever planting bed and density. The flat land - density 70,000 plants/ha combinaison was illustrated with the D leaves biomass the highest (80.20 g). The weight of the fruit beingrelated to the plant’s growth during the floral induction therapy, at the end of the vegetative phase, the results could contribute to improving the production of MD2 pineapple in locality of Dabou

EFFET DE L’ASSOCIATION DE DIFFÉRENTS CULTIVARS DE BANANIERS (MUSA SPP.) TOLÉRANTS SUR L’INCIDENCE DE LA CERCOSPORIOSE NOIRE CHEZ LE CULTIVAR SENSIBLE "ORISHELE" EN CÔTE D’IVOIRE

The cultivation of bananas in the classical systems by smallholders is seriously threatened by the Black Leaf Streak Disease (BLSD). The chemical and genetic fight methods against this disease showed some limitations and disadvantages. That suggests the possibility of the efficient use of susceptible banana in combination of tolerant hybrids as fight methods. This study is carried out to assess the performances of various prototypes or associations of banana on the control of BLSD. These protocols can reduce pest pressure in banana farm and increase the yield of the cultivar "Orishele" which is susceptible to BLSD. During eight months of vegetative growth, the varietal association prototypes of banana had shown variable effectiveness face the disease according to the pathological descriptors. "Orishele" cultivar in association plots showed high tolerance level against BLSD than those of non-association plots. In the prototype with a low density of the cultivar "Orishele", the severity indices of the disease were low. When "Orishele" was associated with the tolerant hybrid PITA 3 or the variety "Figue Sucrée", the severity indices were respectively 10.99 % and 11.07 %.When "Orishele" is on non-association plots the severity indices was high (33.47 %). Banana cultivation in combination of susceptible and tolerant varieties in almost equal proportions seems an ideal strategy to slow the spread of the fungus causing BLSD and provide better yield at harvest of susceptible cultivars to the BSD

4. YouTube in Academic Teaching: A Multimedia Documentation of Siramori Diabaté’s Song “Nanyuman”

Introduction This chapter expands the documentation of a video recording of the song “Nanyuman” by Mali’s legendary female bard Siramori [Sira Mory] Diabaté (ca. 1925–1989). This unique recording was recently collected in the archives of Radio Télévision Guinéenne (RTG), and was then made available on YouTube. This paper adds a transcription and translation to Siramori’s version of “Nanyuman”, and this enhancing of the YouTube video is an attempt to produce a teaching tool. This contribution ..

Influence of maturity stage of mango at harvest on its ripening quality

Introduction. The subjectivity of the external criteria used for the determination of mango maturity at its harvest led to the search for additional more reliable parameters to determine the optimal harvest maturity and able to replace the external and internal morphological indices. Materials and methods. Some physicochemical characteristics, such as colour of pulp, soluble dry extract, titratable acidity and weight loss, were evaluated on fruits of the cv. Kent (Mangifera indica L.) collected in North Cote d’Ivoire. The days necessary for ripening after harvest were estimated. Measurements were correlated to five maturity stages corresponding to the fruit harvest carried out at (76, 82, 88, 94 and 100) days after flowering. On each date of harvest, batches of 52 fruits were gathered. On half of them, maturation was observed as of harvest, the other half being kept at room temperature and the ripening evaluation then being done at the end of storage. Results. According to the harvest date, the soluble dry extract values varied from 8.3 °Brix to 10 °Brix at fruit harvest, and from 14.2 °Brix to 20 °Brix after ripening of the fruits stored at ambient temperature. Titratable acidity was correlated positively with maturity stage. Time to ripen and weight loss continuously decreased with the fruit maturity. For mangos of the cv. Kent, the date of the most suitable harvest seemed to be at 94 days after flowering. Mangos collected at 100 days after flowering developed better organoleptic characteristics such as sugar content, peel aspect and pulp colour than those of the fruit harvested earlier. Conclusion. Starting from the 94th day after flowering, the mango of the cv. Kent collected under the conditions of the North Cote d’Ivoire develops its best organoleptic characteristics during ripening

Caractérisation et évaluation de la phytotoxicité des filtrats de culture de souches de Mycosphaerella fijiensis issues des principales zones de production de bananes en Côte d’Ivoire

Objectifs : Cette étude a été conduite afin de rechercher la production de toxines par des souches ivoiriennes de M. fijiensis, et d’étudier leur implication dans le développement de la maladie des raies noires (MRN) du bananier, causée par ce champignon. Elle a consisté à déterminer la diversité des métabolites produits par ces isolats fongiques et à évaluer la phytotoxicité de leurs filtrats de culture sur les feuilles de variétés de bananiers présentant au champ un comportement variable à la MRN.Méthodologie et résultats : Pour réaliser cette étude, une caractérisation physico-chimique des filtrats de culture des souches de M. fijiensis a été effectuée. Elle a mis en évidence trois principaux groupes de métabolites secondaires : les saponines, les stérols et terpènes et les alcaloïdes. Le test d’induction de nécroses a été réalisé pour déterminer l’activité phytotoxique des filtrats après leur infiltration dans le limbe des feuilles des bananiers. Les résultats ont montré qu’au bout de 48 heures, seulement certains filtrats de cultures du champignon ont pu induire des nécroses dans les feuilles des variétés de bananiers. La variété partiellement résistante à la MRN (FHIA 23) s’est révélée la plus résistante à la toxicité des filtrats de culture à la différence des variétés très résistante (Calcultta 4) et sensible (Grande Naine) à la maladie.Conclusion et application des résultats : Les souches de Mycosphaerella fijiensis issues de la Côte d’Ivoire sont capables de produire des métabolites toxiques pour les bananiers. Ces toxines participent au développement des nécroses foliaires chez le bananier et sont tout au moins impliquées dans l’extension deces symptômes et par conséquent peuvent constituer un outil simple d’évaluation rapide de la résistance des variétés de bananier à la MRN. Un probable  contournement de la résistance totale de Calcutta 4 peut être envisagé chez cette variété de bananier par M. fijiensis.Mots clés : métabolites secondaires, Mycosphaerella fijiensis, bananier, phytotoxicité, maladie des raies noires, Côte d’Ivoire

Effect of some biopesticides based on essential oil and plant extracts on postharvest mango Stem-end rot disease caused by Lasiodiplodia theobromae

Lasiodiplodia species causing mango Stem-end rot disease (SER) are mainly controlled using synthetic products, which can harm humans and environmental health. Therefore, developing an eco-friendly control method, such as using plant extract products, is imperative. In this study, we evaluated the inhibitory effect of 3 biopesticides based on essential oils (ASTOUN 50 EC, FERCA 50 EC, and NECO 50 EC) at 300, 500, 700, 1000 ppm and Moringa oleifera leaves extracts (Methanolic and aqueous) at 5, 10, 15 and 20 g/250 ml on mycelial growth of Lasiodiplodia theobromae in vitro. Subsequently, 135 fruits (cv. Kent) per treatment were inoculated (1 × 105 spores/ml) and treated with each biopesticide (700, 1000 and 2000 ppm) and M. oleifera leaves extracts (15 and 20 g/250 ml) in vivo to evaluate their efficacy on mango SER development. The results showed that the biopesticides ASTOUN (Cymbopogon citratus) and NECO (Occimmun gratissimun) completely inhibited the mycelial growth of L. theobromae at 700 and 1000 ppm. Similarly, M. oleifera methanolic extract has the highest inhibitory rate (65.45 %) compared to aqueous extract (42.44%). Moreover, 1000 and 2000 ppm of biofungicides and 15 and 20 g/250 ml of M. oleifera methanolic extract significantly reduced mango SER development compared to the control. This study provides evidence that these plant extracts are effective alternatives to mango SER management that are consistent with sustainable agriculture principles, promote ecological balance, and reduce the environmental impact of conventional agriculture