Elaboration of a biotic index of pollution using macroinvertebrates for the monitoring of Lake Nokoué in Benin

A study on the relationships between the physicochemical parameters and of the macroinvertebrates of the Lake Nokoué was carried out for the purpose of developing a biotic index of pollution. A total of 96 stations were prospected twice during the flooding and the dry seasons from September 2004 to February 2006. At each station, seven physicochemical parameters were measured and macroinvertebrates were collected. Canonical analyses of correspondence were used to show the relations between the parameters of the environment and the macroinvertebrates. A self-organizing map (SOM) of Kohonen allows the categorization of the studied stations into four groups according to different degrees of pollution. Rough scores were allotted to each taxon according to its abundance in the various groups of stations determined by the SOM for each campaign. A synthesis of the data obtained from the four field surveys allows the assignment of a score to each taxon according to its abundance in the different groups of stations. A biotic index was developed and used for the evaluation of the level of pollution of the stations studied. It then emerged that the borders of the lake present a «poor quality» of water; however, during the dry season there is slight improvement.© 2015 International Formulae Group. All rights reserved.Keywords: Biotic index, pollution, invertebrates, lagoons, Benin, West Afric

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

Elevage en laboratoire de Maruca testulalis (Geyer) sur milieu artificiel simple (Lepidoptera, Pyralidae)

The authors describe the method thanks to which they successfully reared in laboratory the Pyralid pest species Maruca testulalis (Geyer), with very low death rate, the aim of this study was to product suitable entomophagous organisms.Les auteurs décrivent la méthode qui leur a permis d'élever, avec une mortalité larvaire très faible, la pyrale nuisible Maruca testulalis (Geyer), en vue de production d'entomophages appropriés.Atachi Pierre, Ahounou Mathias. Elevage en laboratoire de Maruca testulalis (Geyer) sur milieu artificiel simple (Lepidoptera, Pyralidae). In: Bulletin de la Société entomologique de France, volume 100 (1), mars 1995. pp. 25-28