The potential of Paranosema (Nosema) lucustae (Microsporidia: Nosematidae) and its combination with Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) for the control of locusts and grasshoppers in West Africa

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Perceptions Paysannes des Déterminants de la Faible Productivité des Ignames (Dioscorea spp) et de Leurs Niveaux de Gravité au Sud-Ouest des Savanes Sèches au Togo (Afrique de l’Ouest)

Extensive yam production by means of slash-and-burn cultivation practice holds a prominent place in the south-west of the dry savannahs of Togo cultivation systems. Like in West Africa, yam cultivation in Togo is subject to many constraints that have remained insufficiently known. These constraints lead to lower yields, and volumes of tubers in the field at postharvest, and affect the productivity of this sector. Seeking to identify the main causes of the decline in yam production or productivity in Togo, the present study has carried out a participatory diagnosis with producers and stakeholders in the yam sector in 27 villages in the dry savannah zone of Togo and has identified 15 main factors with severity levels between 0.03 and 3.32. Average losses of yam tubers, seed yield and market value in one cropping season represent 20.62 ± 1.86, 15.72 ± 3.13% and 45.42 ± 5.63% per hectare of 4000 mounds, respectively. The 80/20 law and the ABC analysis have revealed that the variability and instability of rainfall, the continuous decline of soil fertility and the insufficiency of seed are perceived by farmers as constraints to yam production. The study, therefore, indicates that mitigation of these major factors, which account for about 20% of causal factors affecting yam productivity, can improve yam tubers production. However, the high severity of rainfall anomalies mandates future work on local perceptions of the manifestations of climatic variability and the evaluation of local practices for improving the resilience of yam cultivation in the face of climate impacts in Togo. La production extensive d’igname par la pratique de défriche brûlis occupe une place prépondérante dans les systèmes de culture au Sud-ouest des Savanes Sèches togolaises. À l’instar de l’Afrique de l’Ouest, la culture de l’igname au Togo est sujette à de nombreuses contraintes qui induisent une faible productivité des ignames et des pertes post-récolte importantes. La présente étude vise à identifier les principales causes de la baisse de de la productivité des ignames au Togo. Un diagnostic participatif avec les producteurs et les acteurs de la filière igname a été réalisé dans 27 villages de la zone à savanes sèches du Togo. La loi 80/20 et l’analyse ABC ont été appliquées pour l’analyse des données recueilles. Les résultats ont permis de dégager 15 principaux facteurs avec des niveaux de gravité compris entre 0,03 et 3,32. Les pertes moyennes de tubercules d’igname de consommation, de semenceaux et de leur valeur marchande, en une campagne agricole, ont, respectivement, représenté 20,62 ± 1,86 ; 15,72 ± 3,13% et 45,42 ± 5,63% par hectare de 4000 buttes et par campagne agricole. La variabilité et l’instabilité des pluies, la baisse continue de la fertilité des sols et l’insuffisance de semenceaux sont perçus par les agriculteurs comme des contraintes à la production d’igname. La mitigation de ces contraintes majeures peut améliorer la production des tubercules d’igname

Efficacité des pièges à paraphéromone dans la protection des vergers de manguiers greffés contre les mouches des fruits au Togo

Les mouches de fruits en infestant les mangues greffées causent des pertes considérables et un manque à gagner aux différents  acteurs en passant par les producteurs jusqu’aux consommateurs. Pour venir à bout de ces insectes nuisibles, la pulvérisation des insecticides chimiques de synthèse est généralement la solution la plus commune et de premier recours dans toutes les régions du Togo. Mais cette méthode reste dangereuse pour la santé humaine et environnementale et peu rentable économiquement. Cette étude a pour objective de tester l’efficacité du piège Biofeed, une solution alternative, respectueuse de l’environnement et de la santé de l’Homme. Trois vergers d’environ 1 ha pour les trois traitements (piège Biofeed, piège M3 et le control) ont été choisis dans chacune des cinq régions du Togo. Les pièges ont été installés à la prématuration des fruits à une densité de 25 pièges/ha et sont suivis toutes les deux semaines jusqu’à la récolte finale en procédant aux échantillonnages des mangues pour l’évaluation du taux infestation et identification des espèces de mouche de fruits. Après la pose et le suivi des infestations, les pièges Biofeed se sont révélés efficaces en réduisant sur le plan national les dégâts des mouches de fruits de 73,60% tandis que les pièges M3 n’ont entrainé qu’une réductionde 39,94%. Les vergers ayant bénéficiés de ces pièges ont connu des taux d’infestations faibles promettant une bonne récolte. L’incubation des mangues récoltées dans les vergers ont permis de recenser 4 genres de mouches de fruits (Bactrocera, Ceratitis, Dacus, Zeugodacus) et Bactrocera dorsalis est l’espèce la plus abondante retrouvée sur ce fruit d’importance économique. Mots clés : Mouches de fruit, mangue greffée, piège Biofeed, piège M3.   English  title: Efficacy of parapheromone traps in the protection of grafted mango orchards against fruit flies in TogoFruit flies by infesting grafted mangoes cause considerable losses and loss of profit to the various actors range from producers to consumers. To control these pests, synthetic chemical insecticides use is generally the most common and first resort solution in all regions of Togo. But this method remains dangerous for human and environmental health. The objective of this study was to test the effecacy of Biofeed trap, an alternative solution that is environmentally friendly in comparison with a trap already used in the field (M3 traps based on food bait). Three orchards of about 1 ha for the 3 treatments (Biofeed trap, M3 trap and control) were chosen in each of the five regions of Togo. The traps were installed at the premature fruit maturity at a density of 25 traps / ha and were monitored every two weeks until the final harvest by sampling the mangoes for the assessment of the infestation rate and identification of fruits fly species. After setting traps and monitoring the infestations, Biofeed traps proved effective by reducing fruit fly damage by 73.60% nationally, while M3 traps by 39.94%. The orchards that benefited from these traps had low infestation rates that promissing a good harvest. Incubation of the mangoes harvested in the orchards have allowed to identify 4 genera of fruit flies (Bactrocera, Ceratitis,Dacus, Zeugodacus) and Bactrocera dorsalis is the most abundant species found on this economically important fruit.Keywords: Fruit flies, grafted mango, Biofeed and M3 traps

Analysis of strain distribution, migratory potential, and invasion history of fall armyworm populations in northern sub-Saharan Africa

Open Access Journal; Published online: 27 Feb 2018Fall armyworm (Spodoptera frugiperda J.E. Smith) is a noctuid moth pest endemic throughout the Western Hemisphere that has recently become widespread in sub-Saharan Africa. There is a strong expectation of significant damage to African maize crop yield and a high likelihood of further dispersal, putting the rest of the Eastern Hemisphere at risk. Specimens from multiple locations in six countries spanning the northern portion of the infested region were analyzed for genetic markers. The similarity of haplotypes between the African collections was consistent with a common origin, but significant differences in the relative frequency of the haplotypes indicated limitations in migration. The mitochondrial marker frequently used to identify two host strains appears to be compromised, making uncertain previous reports that both strains are present in Africa. This more extensive study confirmed initial indications based on Togo populations that Florida and the Greater Antilles are the likely source of at least a subset of the African infestation and further suggest an entry point in western Africa. The origin of a second subgroup is less clear as it was rarely found in the collections and has a haplotype that has not yet been observed in the Western Hemisphere

Evaluation Au Champ Du Potentiel De Croissance Et De La Production Du Riz (Oryza Sativa L.) Variété IR841 Inoculé En Pépinière Par Quatre Souches De Champignons Mycorhiziens À Arbuscules

The growth and production of rice (Oryza sativa L.) variety IR841 were evaluated in response to arbusular mycorrhizal fungus (AMF) inoculation. Four strains of AMF (Acaulospora spinosa, BEN 10, Glomus mosseae and G. hoi) were tested at 1.96 x 105 ; 3.91 x 105 and 7.82 x 10 5 spores/ha during two growing seasons 2016 and 2017, in a complete random block design. Uninoculated plants and plants fertilized with chemical fertilizer were used as control. The experiments conducted for 19 weeks including 5 weeks in nursery and 14 weeks in field tests showed better development and production of rice in inoculated plants compared to uninoculated controls. The tested rice variety was highly dependent on arbuscular mycorhization. For each strain the rate of mycorhization was dose dependent. The different growth parameters such as the height of the plant, the development of the root system, the total biomass, the number of tillers, the number of fertile panicles per plant, the number of paddy grains per panicle and the paddy grain yield, were positively correlated with the rate of root mycorhization. This study showed that biofertilizers based on mycorrhizal fungi provide important benefits to the plant, and can be used to improve the growth and yield of rice in Togo. The results are discussed in terms of usingAMF as alternative to chemical fertilizer in rice production system

The Glycosyltransferase Repertoire of the Spikemoss Selaginella moellendorffii and a Comparative Study of Its Cell Wall

Spike mosses are among the most basal vascular plants, and one species, Selaginella moellendorffii, was recently selected for full genome sequencing by the Joint Genome Institute (JGI). Glycosyltransferases (GTs) are involved in many aspects of a plant life, including cell wall biosynthesis, protein glycosylation, primary and secondary metabolism. Here, we present a comparative study of the S. moellendorffii genome across 92 GT families and an additional family (DUF266) likely to include GTs. The study encompasses the moss Physcomitrella patens, a non-vascular land plant, while rice and Arabidopsis represent commelinid and non-commelinid seed plants. Analysis of the subset of GT-families particularly relevant to cell wall polysaccharide biosynthesis was complemented by a detailed analysis of S. moellendorffii cell walls. The S. moellendorffii cell wall contains many of the same components as seed plant cell walls, but appears to differ somewhat in its detailed architecture. The S. moellendorffii genome encodes fewer GTs (287 GTs including DUF266s) than the reference genomes. In a few families, notably GT51 and GT78, S. moellendorffii GTs have no higher plant orthologs, but in most families S. moellendorffii GTs have clear orthologies with Arabidopsis and rice. A gene naming convention of GTs is proposed which takes orthologies and GT-family membership into account. The evolutionary significance of apparently modern and ancient traits in S. moellendorffii is discussed, as is its use as a reference organism for functional annotation of GTs

Contribution à l étude de systèmes à diversité d antennes sur terminaux compacts (mesures de performances en environnement réel)

La diversité d antennes consiste à utiliser un système à accès multiples pour améliorer les performances des communications sans fil. Ce manuscrit est consacré à l étude, aux analyses et aux mesures des performances en diversité de réception. En premier lieu, des outils numériques souples et d utilisation très générale sont développés pour calculer les paramètres de diversité dans n importe quel contexte et sans restriction. Ensuite, une étude préliminaire des relations entre les couplages mutuels et les paramètres de diversité montre que les coefficients de corrélation et de couplage devraient être faibles. Cette conclusion a été utilisée pour concevoir et optimiser un terminal compact constitué de deux antennes monopôlaires imprimées fonctionnant dans la bande du WiMax 3.4-3.6 GHz par insertion de fente. Des mesures ont été faites en chambre réverbérante à brassage de modes (CRBM) avec un analyseur de réseaux vectoriel qui délivre une onde CW (constante wave), puis avec un dispositif constitué de deux modules indépendants (émission et réception) de communications numériques. Ce dernier a permis de faire d autres mesures en milieu indoor et dans un contexte milieu indoor vers milieu outdoor . Finalement, une étude analytique permet de montrer que la diversité d antennes et la synthèse de diagrammes sont équivalentes.Wireless communication performances are improved by using multiple antennas or multiple access systems: this is the antenna diversity principle. Diversity studies, its analysis and some measurement results are depicted in this PhD thesis. First, numerical tools that allow the calculation of diversity parameters are developed. These tools are highly efficient since they are independent of any assumption. Second, a preliminary study of the relationships between mutual coupling and diversity parameters is done. The results demonstrated that mutual coupling and correlation coefficients should be preferably low. This conclusion is used to design and optimize a compact terminal that consists of two printed monopole antennas working in the WiMax 3.4-3.6GHz band by a slot insertion for decoupling. Next, measurements took place in a modes stirred reverberation chamber (MSRC) using two different test-beds. The first one used a network analyzer which delivers a constant wave in the chamber. The second one is constituted by two independent digital communication modules (transmission and reception). This latest test-bed allows also measurements in indoor and indoor to outdoor environments. Finally, an analytical study proves that antenna diversity and radiation pattern synthesis are equivalent.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Dépérissement des manguiers et citrus dans la région centrale du Togo et méthodes de lutte par des fongicides

Objectifs: A partir de 2014 une épidémie de dépérissement de manguiers et d’agrumes s’est déclenchée dans la partie centrale du Togo. Cette étude a été entreprise en vue de déterminer le pathogène responsable et d’identifier un pesticide permettant de lutter contre la maladie.Méthodologie et résultats: Une prospection a permis la collecte des échantillons de tissu de plantes malades. Les champignons pathogènes potentiels ont été isolés de ces tissus par culture sur PDA et PDA amendé avec des extraits de manguier. Fusarium solani, Phoma glomerata (27,78 et 16,67% des tissus étudiés) et Lasiodiplodia theobromae ont été isolés mais ce dernier était le plus fréquent et présent dans 83,33% des tissus étudiés. Cinq fongicides disponibles sur le marché local ont été testés. La symptomatologie de la maladie et la fréquence dans les tissus malades ont permis d’identifier L. theobromae comme responsable du dépérissement des manguiers et des agrumes. Tous les fongicides bloquaient la germination des spores de L. theobromae. Le fongicide binaire Banko Plus contenant du carbadazim inhibait le mieux la croissance de L. theobromae.Conclusion: La lutte contre l’épidémie se résume au contrôle de L. theobromae. Dans un premier temps, l’incorporation du Mancozeb au milieu de culture avant son insémination a été plus efficace suivi dans l’ordre par celle du Callomil, du Jumper, du Callicuivre et du Banko Plus. Ce traitement pourrait permettre la prévention de la maladie par blocage de la germination des spores. Deuxièmement, dans le cas de l’aspersion de suspensions de fongicide sur les colonies en croissance sur PDA, le Banko Plus a donné le meilleur résultat. La combinaison de Banko Plus comme fongicide systémique et du Mancozeb comme fongicide de contact devrait permettre la lutte contre le dépérissement du manguier et des citrus au Togo.Mot clef: Dépérissement, Lasiodiplodia theobromae, fongicide systémique, Manguier, CitrusEnglish Title: Dieback of mangos and citrus in the central region of Togo and control methods by fungicidesEnglish AbstractObjectives: Begun in 2014, an epidemic of mango and citrus dieback broke out in the central region of Togo. This study was undertaken to determine the causal pathogen and to identify a pesticide to control the disease.Methodology and Results: A survey was conducted to collect tissue samples from diseased plants. Potential pathogenic fungi were isolated from these tissues by cultivating them on PDA and PDA amended with mango extracts. Fusarium solani, Phoma glomerata (27.78 and 16.67% of the tissues studied) and Lasiodiplodia theobromae were isolated but the later was more frequently encountered and present on 83.33% of studied tissues. Five fungicides available on the local market were tested. The symptoms of the disease and the frequency in the diseased tissues pointed to L. theobromae as the main causal agent. All fungicides blocked the germination of L. theobromae spores. Banko Plus, a binary fungicide containing carbadazim, best inhibited the growth of L. theobromae.Conclusions and application of findings: The control of the epidemic can be summarized to the control of L. theobromae. Firstly, the incorporation of Mancozeb into the culture medium before its insemination was the most effective followed in order by Callomil, Jumper, Callicuivre and Banko Plus. This treatment blocks spores germination and could be used to prevent the disease. Secondly, in the case of spraying of fungicide suspensions on growing colonies on PDA, Banko Plus gave the best result. The combination of Banko Plus, used as systemic fungicide, and Mancozeb, as contact fungicide, should be effective in controlling the dieback of mango and citrus in Togo.Keyword: Dieback, Lasiodiplodia theobromae, systemic fungicide, Mango tree, Citru

Postharvest insect infestation in maize grain stored in woven polypropylene and in hermetic bags

Maize was artificially infested with either 10 or 25 individual Prostephanus truncatus (Horn) and Sitophilus zeamais (Motschulsky) or a mixture of both, and stored in a hermetic grain bag (HGB) or a woven polypropylene bag (WPB) for 150 days. Population growth of P. truncatus and S. zeamais during storage was low in HGB, while in WPB, the insect population increased significantly with storage duration. Mortality rate during storage was significantly higher in HGB than in WPB. After 60 days of storage, the average mortality rate of 99.50% was observed in HGB infested with 25 P. truncatus, and 100% for S. zeamais at the same infestation density after 90 days of storage. Grain losses were significantly lower in HGB compared with WPB. Less than 0.5 and 6.0% losses were obtained, respectively, for S. zeamais and P. truncatus in HGB infested with 25 individual insects after 150 days of storage, whereas losses of 19.2% (infestation with S. zeamais) and 27.1% (infestation with P. truncatus) were observed in WPB. HGB seems to be resistant to the perforation of S. zeamais, but not to P. truncatus. The moisture content of maize grains stored in HGB remained practically the same during storage, compared with the levels in WPB, which reduced with storage time. WPB could be used for maize storage, protecting it against insect infestation without the need for insecticide use