Substances inertes et plantes à effet insecticide utilisées dans la lutte contre les insectes ravageurs des céréales et légumineuses au Sénégal et en Afrique de l’Ouest

La situation alimentaire est caractérisée au Sénégal et dans le Sahel par l’insuffisance des récoltes à laquelle s’ajoutent des pertes souvent élevées dues en grande partie aux attaques des insectes ravageurs au champ et dans les lieux de stockage. En Afrique subsaharienne, l’action des insectes déprédateurs de céréales et de légumineuses peut anéantir complètement, en quelques mois seulement, des stocks destinés aux vivres et aux semences si aucune protection n’est appliquée. Pour y apporter des solutions, les producteurs ont recours le plus souvent aux pesticides de synthèse. La résistance des insectes, les intoxications et les pollutions liées à l’utilisation des pesticides constituent de sérieux problèmes environnementaux et de santé publique. C’est ainsi que ces dernières années, de nombreux travaux ont été menés pour proposer des méthodes alternatives de protection, peu coûteuses et qui respectent l’environnement. Les insecticides naturels tels que les plantes à effet insecticide et les substances inertes (sable, cendre, terres à diatomées,…) méritent d’être valorisées afin de réduire l’utilisation des insecticides chimiques et protéger l’environnement. Ce travail basé sur une revue documentaire fouillée et actualisée vise à faire la genèse des méthodes alternatives de lutte contre les ravageurs des denrées en stockage en mettant l’accent sur les insecticides naturels et les substances inertes susceptibles d’améliorer la protection des récoltes sans danger. Les principales pratiques de stockage sont passées au peigne fin.Mots clés: Céréales, légumineuses, post-récolte, pesticides, substances inertes, plantes insecticides

Efficiency of Traditional Maize Storage and Control Methods in Rural Grain Granaries: a Case Study from Senegal

Maize storage and pest control method as practiced in traditional clay granaries in the Kédougou region in eastern Senegal were evaluated under rural conditions during two successive years. Three storage modes, i.e. maize cobs, winnowed and non-winnowed maize grains, were tested in seven granaries where the insecticidal plants Hyptis spicigera or H. suaveolens were either incorporated in the store structure or deposited as layers intermittently with maize. At the beginning of the storage period, all granaries were artificially infested with 7 pairs Tribolium castaneum and Sitophilus zeamais. No damage, losses or live insects were observed during 7 months of storage when maize cobs were placed between layers of H. spicigera. Compared with the control, incorporation of insecticidal plants within the granary bottom had no significant effect on the damage and loss level irrespective of the storage mode. Non-winnowed maize always suffered less damage and losses than the winnowed variant. In all granaries depredation, insect abundance and moisture content were highest toward the end of storage period between June and July

Typologie des systèmes de stockage et de conservation du maïs dans l'Est et le Sud du Sénégal

Typology of maize storage and conservation systems in the East and the South of Senegal. A survey was conducted in Senegal in the Eastern departments of Tambacounda, Bakel and Kedougou and in Casamance mainland in the departments of Kolda, Sedhiou and Velingara encompassing 330 maize users in 185 villages. Six major types and two modes of storage were found. Differences are presented in relation to ethnic groups who do not adopt the same methods of storage. The impact of types and storage methods are reviewed with regard to loss levels, perception of the producers on the main storage determinants, specificities inherent to ethnic groups, localities as well as pesticides and natural products used in post-harvest treatment

Importance nutritionnelle du manioc et perspectives pour l'alimentation de base au Sénégal (synthèse bibliographique)

Nutritional importance of cassava and perspectives as a staple food in Senegal. A review. Cassava is one of the main plants and starchy roots grown in the world. In 2008, the total yield of cassava in West Africa represented 29% of the world production. However, in many West African countries such as Senegal, cassava is not used as a staple food. In fact, the processing techniques used for cassava are poorly known. In addition, the chemical composition of local cassava varieties has not yet been determined, nor has their toxicity been assessed. In 2004, showing an aggressive agricultural policy and revived interest, the Senegalese government launched a major program for intensifying the production of cassava for food security purposes. Cassava is an important source of calories and can be an interesting option for imported rice and wheat. Although many food products made from cassava are well known in the region, their use in the Senegalese diet is rare. Nevertheless, these cassava products are found as delicacies in some restaurants, and are consumed by the Senegalese and many other Africans. The objective of the present study is to demonstrate the nutritional value and the dietary possibilities of using cassava as a staple food in Senegal