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Grasshoppers and locusts are important pests in the Sahel zone with a big economic and environmental impact. The move towards biological control methods represents an important option to mitigate environmental impact linked with the use of insecticides for their control.Metarhiziumacridum, a locust pathogenic fungus that gave excellent test results in controlling grasshoppers, was further developed as biopesticide. The stability of the manufactured biopesticide in operational conditions was tested. In the present study, the germination of spores and mycelial growth of M. acridum were higher at 28 °C and 33 °C. Higher temperatures led to a significant decrease of these biological parameters. The sporulation of M. acridum is abundant at 28°C and 33 °C but was completely inhibited at 37 °C. Furthermore, M. acridum based biopesticide showed a good infection rate for the dry spores formulation for 3 months of storage in all test sites. In the oil formulation in contrast, infectivity rate dropped quickly to a very low level after one month storage in the inland sites and remained good in Dakar. High temperatures and low moisture, away from the coast were speculated to be the reasons.

In rural areas, the local population draws from several forest resources needed for survival including food. Then it is a granary for these native people. Unfortunately, useful wild plants are highly threatened, especially by various human activities. Because of this situation we started with open semi-structured interviews to identify wild fruit plants, their consumed organs and their seasonality in the rural community of Tomboronkoto. Tomboronkoto is located at the edge of the Niokolo-Koba National park (Senegal) and is mainly inhabited by Malinke. We identified 45 wild fruit species belonging to 38 genera that can be divided in 28 botanical families. The more diversified are successively the Anacardiaceae, Tiliaceae, Apocynaceae and Caesalpiniaceae. More than half of the plants inventoried are trees (53%). We can distinguish three categories of fruits depending on their Fidelity Level (FL) that informs us about their popularity: the well-known or common fruits, moderately known fruits and little known fruits. A dozen wild fruits happen to be greatly appreciated with very high fidelity level (100% to 84%). The fruits of Saba senegalensis, Adansonia digitata, Parkia biglobosa, Tamarindus indica and Vitellaria paradoxa are the most variously used because they are appreciated being fresh or cooked. Only fruits of Ficussur are available all year long. The large majority of the most consumed fruits are available between the end of the hot dry season until the middle of the rainy season. This period coincides with the period where crops from the previous rainy season are depleted and the new crops are not yet ripe. Thus, these wild fruits would greatly contribute to food security in this area during the lean period.

La caracterisation biochimique de 11 cultivars de bissap a ete menee afin de comparer leurs teneurs en elements nutritifs et de determiner la meilleure periode de recolte des feuilles. Les plants ont ete produits au Centre pour le Developpement de l’Horticulture (CDH) suivant les recommandations du guide de production du bissap de l’Institut Senegalais de Recherches Agricoles (ISRA). Des echantillons de 100 g de feuilles fraiches ont ete preleves au hasard sur des plantes de chacun de ces cultivars. Ces prelevements ont ete effectues a quatre (4) dates durant le cycle de developpement vegetatif. Les analyses biochimiques ont ete faites a l’Institut de Technologie Alimentaire (ITA) selon les methodes AOAC. La teneur moyenne en elements nutritifs des feuilles a ete comparee a celle du chou, mais egalement evaluee a differentes dates durant le cycle de developpement vegetatif des plantes. Les resultats montrent que les feuilles de bissap sont riches en elements nutritifs. Une difference existe entre le type rouge et le type vert. Bien que les feuilles du type vert soient les plus consommees, le type rouge a une teneur plus elevee en acidite, vitamine C, calcium et phosphore, alors que, la teneur des autres elements chimiques (proteines, matieres grasses, cendres, cellulose, fer et valeur energetique) est sensiblement la meme. Les feuilles de bissap montrent une teneur plus elevee en proteines, vitamine C, fer et calcium que le chou. La date optimale de recolte pour beneficier de plus de fer, proteines et acidite se situe a 97 jours apres semis. © 2017 International Formulae Group. All rights reserved. Mots cles: Cultivars, bissap, periode optimale de recolte, elements nutritifs, Senegal English Title: Using biochemical parameters to identify the recommended optimal harvest time of Roselle’s ( Hibiscus sabdariffa L.) leaves in Senegal English Abstract Biochemical characterization of 11 cultivars of Roselle was conducted to compare content of micronutrients and determinate the recommended optimal harvest time of leaves to maximize on the nutrients. Plants were grown at the research station of Center for Horticulture Development (CDH) following the technical guideline of Senegalese Research Institute for Agriculture (ISRA). A sample of 100 g was collected at random on plants of each cultivar. Sampling was done at 4 dates during whole cycle of plant growth. The biochemical analysis was done by Food Technology Institute (ITA) in Senegal, using AOAC methods. The average nutrients content of Roselle leaves was compared with cabbage content. Our results show that Roselle leaves content more nutrient than cabbage. Roselle green type and red type show difference in nutrient content. Even though the green type is commonly consumed, the red type is richer in acidity, vitamin C, calcium and phosphorus. However, nutrient content of proteins, fat, ash, celluloses, iron and energy are similar. Roselle leaves show high nutrient content in proteins, vitamin C, iron and calcium than cabbage. The best date to harvest leaves for high level of iron, proteins and acidity is 97 days after sowing. © 2017 International Formulae Group. All rights reserved. Keywords: Cultivars, roselle, best harvesting period, nutrient content, Senegal

African eggplant (Solanum aethiopicum L. and S. macrocarpon L.) is one of the most commonly consumed fruit vegetables in tropical Africa, in quantity and value probably the third after tomato and onion. Commercial production for supply to the cities is increasing. Roselle (Hibiscus sabdariffa L.) is another important vegetable crop in sub-Saharan Africa; its leaves, seed, and calyces are eaten. Roselle leaves and calyces are nutritious and rich in iron, β-carotene, and ascorbic acid. Although there is a market for African eggplant and Roselle, farmers have been slow to adopt new improved varieties due to use of traditional breeding method. To increase adoption rates of new varieties, we used a participatory varietal selection process to identify new varieties of both plants based on fruit yield, leaf, calyx traits, and consumers’ preference. Fifteen lines and varieties of each species from several African countries were evaluated in Bamako, Mali during the 2008 hot rainy season. A randomized complete block design with three replications was used for the selection process. Twenty-two vegetable farmers and traders (or users) from Bamako rated the African eggplant and Roselle varieties based on visual characteristics (fruit color, fruit shape, number of fruits per plant, fruit size, number of secondary branches per plant, leaf size, leaf shape, leaf color, number of calyces per plant, calyx shape, and calyx color). Using a scale from 0 (least preferred) to 5 (most preferred), the varieties and the criteria were ranked, to identify the best variety and the most important criteria. In addition, agronomics data of African eggplant (number of fruits per plant, marketable yield, fruit weight, fruits shape and fruit color) were collected. Agronomics data were also collected on Roselle calyces (number of calyces per plant, fresh calyces yield, dry calyces yield, dry matter and calyces color based on stem color) and leaves production (leaf length and width, economic yield, leaf shape and stem color). African eggplant line L10, varieties Soxna and Locale Gaya were highly rated for their visual appeal and have the potential to out-yield the local Malian variety. The fruit color and fruit shape, classified top two criteria through participatory selection criteria are important in the choice of users. For leafy entries of Roselle, leaf size was the most important trait. Samandah and line L28 were rated higher than the local check variety (Dah Rouge) for all traits. For calyx varieties of roselle, the number of calyces per plant was the most important trait. For leafy and calyx varieties, the agronomic evaluation show that yield is not a very important criterion in the choice of the users.

Plant viral diseases are the most important pathogen attack tomato particularly of which is Tomato yellow leaf curl virus (TYLCV). Obtaining stable and durable resistances seems the most effective solution for controlling the disease. In this context, a breeding programme with two steps was conducted in the Niayes ecological area of Senegal: i) 41 tomato varieties from different origins were screened to assess their reaction to TYLCV disease, ii) 12 resistant varieties and two susceptible were tested in an experimental field. The first step was a preliminary trial in unreplicated plots, to identify promising varieties. However, disease assessments (incidence and severity) were done three times and we used longitudinal data analyses to classify the varieties for resistance. Yields in t/ha were also measured for the different varieties. Among our accessions, Roma VF and Xina known for their susceptibility, and Nadira known for its tolerance, were used as controls. Our results revealed 12 resistant varieties, 16 tolerant varieties and 8 susceptible varieties. The yield values were well correlated to the resistance measured by both incidence and by severity right from the second date of symptom observations, at the time of flowering. TYLCV disease is thus one of the main factors limiting tomato-growing the Niayes agro-ecological area. The second step of the selection process was done in a complete block design with three replications. This trial allowed a confirmation of the 12 resistant varieties. The final selection of the varieties took into account the other traits, like yield and traits related to the fruit characters. (Resume d'auteur)

Summary Floating stems of Jussiaea repens L. develop two kinds of roots: absorbing downward growing roots and spongy, upward growing roots. The determination of this developmental pattern was studied. Apex and leaves had inhibiting and stimulating effects, respectively on root organogenesis. Changes of dorsiventral polarity and growth-regulator applications (NAA, GA, BAP) induced modifications of root organogenesis and differentiation. The results suggest that root differentiation is controlled by the ratio of auxins and cytokinins.