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L’utilisation des champignons mycorhiziens arbusculaires (CMA) améliore durablement la baisse de la fertilité des terres et donc les rendements. Cette étude avait pour but d’évaluer la densité et la diversité des CMA associés à la culture du maïs (Zea mays L.) dans différentes zones agro-écologiques (ZAE) du Bénin. Des échantillons (sols et racines) ont été prélevés dans 38 champs répartis dans sept ZAE. Les propriétés chimiques et la densité des spores des CMA ont été déterminées à partir des échantillons de sols. La diversité des CMA a été déterminée par les indices de diversité. Les échantillons de racines ont servi à déterminer la fréquence et l’intensité de mycorhization. Les résultats obtenus ont montré la présence des CMA dans les ZAE enquêtées. Une variation de la densité en spores des CMA (p 0.05) among the studied AEZ. The results from the correlation test indicated a highly relationship between chemical parameters and spore density on the one hand, and between chemical parameters and indexes of biological diversity on the other hand.© 2019 International Formulae Group. All rights reservedKeywords: Arbuscular Mycorrhizal Fungus, Zea mays L., diversity, agro-ecological zones

Objectives: Fusarium wilt is the first oil palm pathology, who devastates the plantations in Africa. The currents study aims to diagnose the spatial distribution of this pathology and the incidence of the disease caused by Fusarium oxysporum elaeidis (Foe) in the palm oil growing zone of Benin.Methodology and Results: Thus, a survey was carried out in May 2018 covering 16 plantations distributed in four agroecological zones of production of palm oil in Benin. In each plantation, 15 plants were randomly inspected to evaluate the incidence, the severity, and the distribution of the disease. Root and soil samples were collected at the foot of each evaluated tree, at a depth of 20 cm using an auger. Samples were stored in polyetilene bags, for the detection and isolation of the pathogenic agent. The results showed that incidence is significantly different depending on the agroecological zones prospected (p=0.000). Central Cotton Zone (Kétou) and the Fisheries Zone (Adjohoun) recorded an incidence of vascular wilt of 0%, whereas on the sites surveyed in the Depression Zone (Pobè, Adja-Ouèrè) and the Bar Land Zone (Ifangni, Missérété, Sakété, Adjarra) the recorded disease incidences were 30.0% and 12.5%, respectively. This study also revealed an uneven distribution of the pathogen on the sites surveyed. Indeed, the study of the soil samples taken at the foot of the plants revealed that the presence of Foe does not systematically induce the disease, or induces it to varying levels, although the isolate is pathogenic and the material planted on each site is identical.Conclusions and application of results: These results demonstrate a polymorphism of oil palm susceptibility to Fusarium wilt and underline the need to define a new screening approach based on the susceptibility factors of oil palm and which minimizes the intra-crossing variations observed.Keywords: Fusarium oxysporum f. sp. elaeidis, incidence, severity, symptoms oil palms

We report the results of a large-scale study from 2005 to 2009 on seasonal population fluctuations of fruit flies (Diptera: Tephritidae) in mango and cashew orchards in the Borgou Department, Benin. During monitoring in mango, over 2 million specimens from 25 species were captured, including three species of Bactrocera, 11 of Ceratitis and 11 of Dacus. We observed significant differences in Bactrocera dorsalis counts between high and low mango production years from 2005 to 2008, but not in Ceratitis cosyra counts. The native species, C. cosyra, was the most abundant species during the dry season, reaching peak populations in early May, while the exotic species, B. dorsalis, was the most abundant species during the rainy season, peaking in June. Preliminary results underlined the role of nine species of wild hosts and seven cultivated species around mango orchards that played an important role in maintaining B. dorsalis in this Sudan zone all year round. C. cosyra was present during nine months of the year. During the first 14 weeks of monitoring in cashew orchards situated near mango orchards, most flies (62%) were captured in traps in cashew orchards, showing the importance of early fruit fly control on cashew before the mango season. Based on these results in Benin, we propose that the effective and compatible control methods for C. cosyra proposed in the IPM package of the West African Fruit Fly Initiative (WAFFI) project, initially developed in Benin, should be extended in a large regional tephritid control program in similar zones of West Africa. (Texte intégral)

Fruit flies (Diptera: Tephritidae) are widespread frugivorous pests of economic importance infesting some fruit species in Benin, such as Mangifera indica, Psidium guajava, Vitellaria paradoxa, Annona senegalensis and Sarcocephalus latifolius. The objective of this study was to obtain information on the parasitoids of Ceratitis cosyra and Bactrocera dorsalis. The study was conducted in four townships (Tchaourou, Parakou, N'Dali and Bembérékè) in the Department of Borgou, Benin, from April to October 2009. A total of 7270 fruits were collected from the five fruit species and the four districts, taken to the laboratory and placed on sand in gauzecovered containers to collect pupae and parasitoids. Pupae were collected every 5 days by sifting the sand. We obtained 54,171 pupae from which six fruit fly species emerged, the two dominant species being C. cosyra (69.7%) and B. dorsalis (11.8%). Seven species of parasitoids were collected; Fopius caudatus, Tetrastichus giffardianus, Pachycrepoïdeus vindemmiae, Fopius silvestri, Diachasmimorpha fullawayi, Psyttalia cosyrae and Psyttalia concolor. Fopius caudatus was the main parasitoid species collected in the study. Moreover, among the cultivated fruit species, M. indica (mango) had the highest fruit fly infestation rate (average of 32.2 pupae/kg fruit), while fruit flies from P. guajava (guava) were the most parasitized. Generally, the wild fruit species had more fruit fly infestation which was more parasitized than the cultivated species. (Texte intégral)

* In Benin cashew plantations, yields and nut quality are lost mainly as a result of insect pests. In the present study, we investigated the effectiveness of the African weaver ant Oecophylla longinoda as a biocontrol agent against Beninese cashew pests. * In a 2-year study, nut yield and quality were compared among: (i) trees with weaver ants O. longinoda; (ii) trees where weaver ants were sugar-fed; (iii) integrated pest management (IPM) trees with weaver ants combined with fruit fly bait spray; and (iv) control trees receiving no control measures. * All treatments with ants showed significantly higher yields than the control, with the IPM treatment leading to the highest yield. Compared with the control trees, the ants, ant sugar-fed and the IPM trees produced 78%, 122% and 151% more nuts, respectively. Nuts produced on control trees were of a higher quality on average because they were less damaged by thrips (probably because the fruit fly bait worked as a contact poison on thrips); this was also the case for the IPM treatment. In absolute numbers, however, trees in ant treatments produced more first-quality nuts. * To achieve a broader and effective control of both coreid bugs and thrips, a combination of weaver ants and supplementary compatible control measures is recommended.

Weaver ants (Oecophylla spp.) are widely used as effective biological control agents. In order to optimize their use, ant abundance needs to be tracked. As several methods have been used to estimate ant abundance on plantation trees, abundances are not comparable between studies and no guideline is available on which method to apply in a particular study. This study compared four existing methods: three methods based on the number of ant trails on the main branches of a tree (called the Peng 1, Peng 2 and Offenberg index) and one method based on the number of ant nests per tree. Branch indices did not produce equal scores and cannot be compared directly. The Peng 1 index was the fastest to assess, but showed only limited seasonal fluctuations when ant abundance was high, because it approached its upper limit. The Peng 2 and Offenberg indices were lower and not close to the upper limit and therefore showed fluctuations throughout the season. The numbers of nests showed high fluctuations unlikely to reflect ant abundance, but rather reflected nest building behaviour influenced by tree phenology. In conclusion, nest counting is not recommended, whereas the Peng 1 index can track dynamics at low ant abundance and the Peng 2 and Offenberg indices can be used in most situations.

The mango tree is rustic and voluminous; it provides both a food staple and protection. In northern-central Benin, as in other similar agro-ecological zones in neighboring countries, the mango serves as a fruit crop and as a subsistence crop for family farms. As it ripens at the end of the dry season and at the start of the rainy season, the mango is a fundamental source of nutrition for rural populations living in the Soudano-Sahelian regions of West Africa: it is rich in potassium, alphacarotene, vitamin C and calcium. Increased production and marketing of undamaged mangoes are important in reducing poverty, particularly in northern-central Benin (Soudanian areas). According to our survey on location of mango production in Benin, about 75% of mango orchards are concentrated in the Borgou district (Soudanian area). In Benin, and more generally in Sub-Saharan Africa, over 90% of mango production is ensured by small family farms with low financial investment capacity. In Benin we can find three fibrous poly-embryonic types of "mangots" and 29 grafted mono-embryonic mango cultivars. The most abundant mango cultivars (grafted) are Gouverneur, Zill, Eldon, Ifac 3, Springfels, Dabshar, Ruby, Kent, Palmer, Smith, Keitt, Brooks. In 1994, an estimation assessed the area devoted to mango trees in Benin at 1191 ha, total production being 10,166 t, and average yield per ha being 8.5 t. Assessments reveal that Beninese mango producers are confronted with three main connected problems namely (i) deterioration of fruit quality due to fruit flies, (ii) saturation of the national market leading to wastage and lower prices and (iii) lack of post-harvest promotion. More than 60% of mango orchards belong to the "Gatherer production system" in Borgou district. Mango-infesting fruit flies as Ceratitis cosyra and Bactrocera invadens (Diptera Tephritidae) became the target pests in Benin as in other West African countries. About the fruit fly issue, IITACIRAD has developed a Regional Fruit Fly Control Project also called West African Fruit Fly Initiative (WAFFI) based at the IITA station of Cotonou. WAFFI has developed Researches for Development in Benin and is proposing an IPM-package to control/reduce the damage of fly species by taking into account the socio-economic aspect of the method at producer level. Mango fruit processing overcomes many post-harvest problems and add value to the product. Currently, it may be noted that in Benin, the share of processed fruit is a tiny proportion of total production. Few organizations/projects are dealing with this fruit processing activities among which we can mention as leader: "Centre de Transformation des Fruit Tropicaux" (CTFT); Songhai NGO; the Monastery in Parakou; and the "Programme de Technologie Alimentaire" (PTA), which is part of the National Institute for Agricultural Research (INRAB).

Considering the different commodities, the mango production plays a major role in terms of realization of food security and improvement of the livelihood of the rural populations in Burkina. Mango represents about 50% of the fruit production in Burkina Faso and plays an important nutritional role for populations living in rural area as a fruit crop and also as a subsistence crop for family farms. The major mango growing areas are located in the Southwest part providing 75% of the national mango production and the Western-central part of the country, both located in the Sudanian agro-ecological zone (sensu lato). Mango orchards occupy 15,000 ha i.e 75% of the total area occupied by the fruit crops, and annually produce 120,000 tons. Mango is the main crop in Burkina where it covers about 14 000 ha representing 58% of the surface of all perennial crops. The mango production has generated more than 374,483 jobs in Burkina Faso. In terms of income, mango producers earned about 30.4 billion of FCFA and traders 6 billion of FCFA in 2008. The mango value chain is using about sixty units of transformation including an industrial unit of pulp and juice production. In Burkina Faso, the total number of mango cultivars has been estimated to 30. However 7 main cultivars are cultivated They are Amélie, Kent, Keitt, Valencia, Lippens, Springfels, and Brooks. Kent and Keitt are the two most exported cultivars. Assessments reveal that Burkinabe mango producers are confronted with two main connected phytosanitary problems namely (i) deterioration of fruit quality due to fruit flies, (ii) bacterial black spot (BBS). Mango-infesting fruit flies as Ceratitis cosyra and Bactrocera invadens (Diptera Tephritidae) became the main target pests in Burkina as in other West African countries. Pre harvest diseases in Burkina Faso includes now bacterial black spot (BBS) caused by Xanthomonas campestris pv. mangiferaeindicae causing bacterial canker in Burkina since 2011. Apart from the mangoes exported fresh (conventional, the organic and/or fair-trade certified mangoes), a substantial share of the mangoes is being processed into dried mango, juice and pulp, for domestic and export markets (FAO, 2010). Mango processing contributes to overcoming the hurdle of mango rotting and drains foreign exchanges to the country. The industrial processing of mango started in Burkina Faso in 1980 with the installation of the first drying factories supported by the national government. They are well developed. Three types of value added chains are commonly observed for mango production in Burkina Faso (i) the traditional value chain (fresh mango for local market), (ii) the modern/ urban processing value chain (fresh mango for modern markets or processed mango (dried/juice) for export markets, and (iii) the export value chain (export value chain: fresh/fresh cut).

Field observational studies on circadian activity pattern of Oecophylla longinoda (Latreille) were carried out during two consecutive years in a mango orchard of the Sudanian zone of Benin. Preliminary results show that circadian activity of weaver ants is continuous although diurnal activity is greater than nocturnal activity. The consistency of the pattern suggests circadian internal clock regulation through light, temperature and humidity as its zeitgeber primary elements. Seasonal periodicity seems not to act on weaver ant activity between dry, rainy and harmattan seasons. Laboratory experiments now need to be implemented to check and complete these field results, and to screen for these three abiotic factors and others of potential relevance. Cultivars with thin foliage and modest canopies sheltered more nests than those with thick foliage and a dense canopy. This study raises practical issues on the use of biological control agents to improve weaver ant management and these are discussed.

Les fruitiers locaux des zones Guinéo-Soudaniennes (sensu lato) du Bénin présentent un intérêt remarquable, mais ils sont généralement sous-exploités. Cette étude préliminaire a permis de réaliser un premier inventaire, d'identifier leur période de fructification et d'estimer les dégâts dus aux mouches des fruits (Diptera Tephritidae) pour les principales espèces. Les échantillonnages de fruits ont été effectués toutes les semaines durant leur période de production et leur taux d'infestation par les Tephritidae a été calculé après émergence des insectes au laboratoire. Dans les départements Alibori, Atacora, Borgou, Donga et Collines nous avons recensé une vingtaine d'espèces fruitières présentant des périodes de fructification étalées de mars à octobre. Les principales sont Adansonia digitata L., Annona senegalensis Pers., Chrysophyllum albidum G. Don, Irvingia gabonensis (Aubry-Lecomte) Baill., Saba senegalensis (A. DC.) Pichon, Sarcocephalus latifolius (Smith) Bruce, Sclerocarya birrea (A. Rich.) Hochst., Vitellaria paradoxa C.F. Gaertn., Ziziphus mauritiana Lamk. L'étalement de leur production constitue une opportunité à valoriser pour les populations rurales. De 2005 à 2008 leur taux d'infestation moyen par les Tephritidae a varié entre 34 et 188 pupes/kg de fruits. La pulpe de la grande majorité de ces fruits est exploitée par les larves de plusieurs espèces de cératites et par une redoutable espèce invasive arrivée il y a quelques années en Afrique Sub Saharienne, Bactrocera invadens. La lutte intégrée contre ces ravageurs est à développer au niveau des bassins de production fruitiers tant cultivés que locaux. De plus, une meilleure valorisation de ces essences est à promouvoir à travers leur protection et une intensification écologique de production.

L'efficacité du GF-120 (Dow Chemical), dont l'insecticide est le spinosad, a été évaluée dans le cadre de la lutte contre les mouches des fruits (Diptera: Tephritidae) inféodées au manguier en comparant les résultats de 6 vergers traités par rapport à ceux de 6 vergers témoins très proches des précédents et comportant les mêmes cultivars. Les traitements par taches (un m² / arbre) avec le GF-120 ont été effectués de façon hebdomadaire durant 9 semaines en 2006 et 12 semaines en 2007. Douze vergers de manguiers, Mangifera indica L., situés dans six villages (deux vergers par village: l'un traité et l'autre témoin) tous localisés dans le Borgou (Bénin) ont été suivis toutes les semaines par un piégeage de détection et avec un échantillonnage de fruits afin de détecter le taux d'infestation larvaire par les mouches des fruits. Les deux périodes d'échantillonnage se situaient au début et au milieu du mois de mai en 2006 comme en 2007. Les deux principales espèces de mouches des fruits sont Ceratitis cosyra (Walker) et Bactrocera invadens Drew Tsuruta and White, une espèce exotique qui a très rapidement envahi toute l'Afrique de l'Ouest. Durant les campagnes 2006 et 2007, C. cosyra avait un pic de population précoce (en saison sèche) et les différences (nombre de mouches / piège / semaine) n'ont été significatives, entre vergers traits et témoins, qu'en 2007. Les populations de B. invadens ont augmenté très rapidement après les premières pluies utiles (à partir de début mai) et il n'y avait pas de différences significatives entre vergers traités et témoins. En 2006 et 2007, l'infestation larvaire des fruits par B. invadens était significativement plus faible dans les vergers traités avec le GF-120 que dans les vergers témoins. Les traitements avec le GF-120 ont apporté une réduction de 81 % au niveau du nombre de pupes par kg de fruit frais suivant chaque application hebdomadaire durant 9 semaines en 2006 et une réduction de 89% durant 12 semaines en 2007. La possibilité du couplage de ces traitements par taches avec d'autres méthodes de lutte est discutée. (Texte intégral)