Ensuring food and nutritional security in light of high climate variability and a rapidly growing population remains a challenge. Mungbean (Vigna radiata (L.) Wilczek) is a short duration, drought-tolerant, and ureide-exporting legume crop capable of symbiotic atmospheric nitrogen fixation. Estimates of biological N 2 fixation by mungbean in different soil textures have not been extensively studied. We conducted this study to evaluate plant growth and N 2 fixation of five mungbean genotypes (Berken, 8735, IC 8972-1, STB#122, 223) inoculated with Bradyrhizobium spp. and grown on loamy sand and silt loam soils under glasshouse conditions. Mungbean dry matter yield, δ 15 N values, shoot content, amounts of N-fixed, and soil N uptake were all higher on the silt loam soil compared to the loamy sand soil, demonstrating the effects of soil properties on plant growth and N 2 fixation potential. Among genotypes, IC 8972-1 produced the highest biomass (7.85 g plant −1), shoot N content (200 mg plant −1), and soil N uptake (155 mg plant −1) than other genotypes. The significant interaction between soil texture and genotypes for root dry matter and %Ndfa indicates the major role of legume root-nodule bacteria in symbiotic N 2 fixation. This study demonstrated that N 2 fixation in mungbean is affected by both genotypes and soil properties, illustrating the need to consider soil properties in order to maximize N contribution from mungbean to agricultural production systems.

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Introduction. Since its arrival in Senegal in 2004, Bactrocera invadens (Diptera Tephritidae) synonymized with Bactrocera dorsalis has caused much economic damage in mango crops. Effective and efficient control activities against B. invadens were necessary in order to continue mango production, and biological control measures were envisaged. In such conditions, the government of Senegal allowed the Asian parasitoid Fopius arisanus to be released in some orchards around Ziguinchor. Materials and methods. The dynamics of fruit fly species was studied with lure traps (methyl eugenol and terpinyl acetate with Dichlorvos). Mango fruit were sampled from the control orchard and orchards with released F. arisanus, to compare the differences in tephritid infestation. Results and discussion. The levels of B. invadens populations were 1.6−2.5 times higher in the control than in orchards where F. arisanus was released. The fruit were also 5-6 times more infested in the control orchard than in those that received F. arisanus. Between May and July 2012 the majority of the pupae (92%) collected from fruit samples developed into adult flies, while only 39% of the pupae transformed to adults between October and December after effective action of the parasitoids. In both orchard treatments, the level of native fruit fly populations was about the same. Wild fruit were infested mostly by Ceratitis cosyra, from which were reared native parasitoids such as Fopius caudatus, F. silvestrii, F. desideratus, Diachasmimorpha fullawayi, D. carinata, Psyttalia cosyrae, and P. concolor. In contrast with Mangifera indica, Citrus spp., Anacardium occidentale, Psidium guayava, Saba senegalensis, and Landolphia heudelotii were mainly infested by B. invadens which showed parasitism by F. arisanus. Pteromalidae and Eulophidae were also found from the pest fly pupae. Killer flies (Diptera: Muscidae) such as Coenosia attenuata Stein, C. atra Meigen and C. tigrina Fabricius emerged from the fruit samples. Conclusion. Sanitation against fruit flies in Casamance should take into account the conservation of natural enemies such as parasitoids and predators for an effective biological control of tephritids. Keywords: Senegal / Casamance / Mangifera indica / mango / fruit fly / Bactrocera invadens / Fopius arisanus / biological control Résumé-Enquêtes préliminaires après lâcher du parasitoïde de la mouche des fruits Fopius arisanus Sonan (Hyménoptère, Braconidae) dans des plantations de manguiers en Casamance (Sénégal). Introduction. Depuis son introduction au Sénégal en 2004, Bactrocera invadens (Diptère, Tephritidae) synonyme de Bactrocera dorsalis, a causé d'énormes dégâts économiques aux cultures de manguiers. Des mesures réelles et efficaces de lutte contre B. invadens se sont avérées indispensables pour continuer à produire des mangues, et des méthodes de lutte biologique ont été envisagées. Dans ces conditions, le gouvernement du Sénégal a autorisé l'importation du parasitoïde asiatique Fopius arisanus afin de le lâcher dans quelques vergers autour d...

Pearl millet [Pennisetum glaucum (L.) R. Br.] yields in Senegal are constrained by rainfall variability, persistent drought, and low soil fertility. Mungbean [Vigna radiata (L.) Wilczek], a short-duration and relatively drought-tolerant legume crop, is capable of improving soil fertility and productivity of associated crops. Our study evaluated the effects of pearl millet and mungbean intercropping on crop yields in the semi-arid regions of Senegal. Field experiments were conducted during the 2017 and 2018 growing seasons at Bambey and Nioro sites located within Senegal's west-central and Saloum agricultural regions, respectively. Experimental treatments: monocropped millet (T 1), monocropped mungbean (T 2 , 100%), and 23% (T 3), 43% (T 4), 47% (T 5), 62% (T 6), 125% (T 7), and 164% (T 8) of mungbean intercropped with millet were laid out in a randomized complete block design and replicated four times. In addition to yield, canopy cover and normalized difference vegetation index (NDVI) were measured and yield advantage was assessed with the land equivalent ratio (LER). Combined millet and mungbean seed yields were up to 60 and 85% higher under intercropping systems compared to millet monocropping at Bambey and Nioro, respectively. Similarly, LER was always greater than unity (> 1) under millet-mungbean intercropping compared to millet monocropping. Mean canopy cover estimates and NDVI values increased by up to 60 and 30% in millet-mungbean intercropping over millet grown alone, respectively. These combined yield gains obtained without fertilizer applications suggested that optimizing mungbean density (62-125%) in pearl millet-based systems can increase the combined yields in a low-input and/or high-risk environment in Senegal.