Potential use of the Bushmint, Hyptis suaveolens, for the Control of Infestation by the Pink Stalk Borer, Sesamia calamistis on Maize in Southern Benin, West Africa

Maize production in Benin, especially in resource-poor farmers' fields, is constrained by stemborers among other factors. One of the major stemborers in southern Benin is Sesamia calamistis Hampson (Lepidoptera: Noctuidae). African farmers cannot afford to use commercial insecticides for controlling stemborers - they are expensive and unsuitable for durable pest management systems due to eco-toxicity. There is therefore a need for cheaper and environmentally friendly methods and botanicals offer an attractive alternative. The bushmint, Hyptis suaveolens (L.) Poit. (Lamiales: Lamiaceae), was compared with the commercial insecticide Furadan (carbofuran) for the control of S. calamistis on maize Zea mays L. (Poales: Poaceae). Trials were conducted in the screenhouse and in the field during the minor cropping season in 2004 at the International Institute of Tropical Agriculture (IITA)-Benin station. The variables measured included numbers of egg masses per plant, eggs per egg mass (in the screenhouse study), population density of S. calamistis, percentage of infested plants and/or ears, and deadhearts in the field. Irrespective of the variable considered, the aqueous extract of H. suaveolens compared favorably with Furadan while maize surrounded by live H. suaveolens plants had lower S. calamistis densities

Using knowledge management to better identify research gaps and priorities on pesticide plants in West and Central Africa

Taking its cue from the European ADAPPT and OPTIONs projects, CIRAD launched a research and development network on Pesticide Plants of Francophone Africa (PPAf) in 2015. I t currently has 55 African members, generally affiliated to universities or to national research organizations, located in 10 countries in sub - Saharan Africa : Benin, Burkina Faso, Cameroon, Gabon, Ivory Coast, Mali, Niger, Democratic Republic of Congo , Senegal, Togo. The network has been completed with 15 correspondents located outside the African continent, mostly in France. Prior to drawing up a project in response to a call, PPAf launched a census of pesticide plants in these countries which were studied. The 74 botanical taxa inventoried, of which 68 were identified at species level, belonged to 29 botanical families. Knowledge on the use of these plants, and on interactions with harmful organisms, has been compiled in a knowledge base. Whether for experimental purposes or for use by producers, the plants are employed in different forms (extracts, essential oils, etc.) against fungi ( 11 species identified ) , seed pests (122 interactions ), insect pests ( 6 species ) in stored foodstuffs (111 interactions ), or insect pests ( 16 species ) on field crops (61 interactions ). Some insect species transmitting animal diseases were also inventoried. This francophone network can be considered as a complement to the African Network of Research on Storage Insects founded in 2008, itself arising from the creation of the African Network on Bruchids described by Dr. I. Glitho in 2002. One of the originalities of the knowledge base is that, by computer processing, it enables the identification of knowledge gaps and thereby helps to define research priorities. (Résumé d'auteur

Landscape changes in a lowland in Benin: ecological impact on pests and natural enemies

Habitat management involving conservative biological control could be a good crop pest management option in poor African countries. A survey was conducted from August 2013 to July 2014 in a rainfed lowland region near Pélébina, northern Benin, in order to characterize spatiotemporal lanscape changes and investigate their influence on the main crop pests and their associated natural enemies. The area was mapped mainly regarding crop fields and fallows. Visual observations were recorded and a database was compiled. Major landscape composition changes were noted between rainy and dry seasons, which affected the presence of both pests and natural enemies. Cereals (rice, maize and sorghum) and cotton were grown in the humid season, and then okra (Abelmoschus esculentus) was the dominant vegetable crop in dry season. These modifications impacted fallow abundance throughout the lowland. Different cotton (e.g. Helicoverpa armigera, Dysdercus sp., Zonocerus variegatus) or rice (e.g. Diopsis Iongicornis, D. apicalis) pests were observed during dry season in okra crops. Dry season surveys of Poaceae in two types of fallows ('humid', 'dry') revealed the presence of very few stem borers: only 0.004% of stems sampled were infested by stem borers, with a mean of 1.13 larvae per stem. Known cereal stem borer species such as Busseola fusca, Coniesta ignefusalis, Sesamia calamistis were not clearly identified among these larvae of their diapausing stage and white color. Unexpected pollinators (Hymenoptera Apidae, genus Braunsapis, Ceratina and Xylocopa) and predators (Crabronidae, genus Dasyproctus) were found in the stems. Sweep-net collection of insects in humid fallows allowed us to describe for the first time in Benin seven Diopsidae species (23% of adults bearing Laboulbeniomycetes ectoparasitic fungi). Some of these species were captured in rice fields during rainy season. Parasitoids (adult Chalcidoidae and Ichneumonoidae) were observed during both seasons but their impact on stem borers was hard to determine, even during the rainy season, due to their low abundance and the difficulty of identification. Predators (Reduviidae, Odonata) were found mainly in humid fallows and rice fields. Regarding our observations, we suggest the presence of alternate host crops such as okra during the dry season for rainy season crop pests. Moreover, fallows also had a real ecological role as a habitat resource for many guilds of insects (pollinators, pests, predators). The management of these landscape components should be the focus of a long-term study with the aim of enhancing pest management of rauny season crop pests. (Résumé d'auteur

Constraints for studying the management of cereal moth borerswith a landscape approach: A case study in North Benin

Landscape ecology is a discipline that has shown an increasing interest to understand certain pest problems and their control by natural enemies in temperate climate. In Benin, in a very different climatic, social and economic context compared to Europe, this approach was carried out in two lowland rice cropping systems during the rainy season, with a specific focus on stem and cob borers. The landscape was mapped and studied regarding its composition and structure and pest species were identified. A high variability of infestation was observed in a context of relatively low pest pressure. This paper presents the preliminary results which still need to be analyzed thoroughly. (Résumé d'auteur