It is difficult to assess pollution in remote areas of less-developed regions owing to the limited availability of energy, equipment, technology, trained personnel and other key resources. Passive sampling devices (PSDs) are technologically simple analytical tools that sequester and concentrate bioavailable organic contaminants from the environment. Scientists from Oregon State University and the Centre Régional de Recherches en Ecotoxicologie et de Sécurité Environnementale (CERES) in Senegal developed a partnership to build capacity at CERES and to develop a pesticide-monitoring project using PSDs. This engagement resulted in the development of a dynamic training process applicable to capacity-building programmes. The project culminated in a field and laboratory study where paired PSD samples were simultaneously analysed in African and US laboratories with quality control evaluation and traceability. The joint study included sampling from 63 sites across six western African countries, generating a 9000 data point pesticide database with virtual access to all study participants.
The effect of hermetic storage alone or in combination with Boscia senegalensis has been evaluated against Callosobruchus maculatus. Analysis of gas concentrations within a 7-day period indicated that O 2 declined from 19.2 to 2.3% and CO 2 rose from 1.2 to 22.8%. Prolonged storage durations increased adult mortality, significantly increased the developmental time and induced 60-80% reduction in the F1 progeny. The use of hermetic storage in combination with B. senegalensis fruits, at 1.2 g/1 (flask volume) reduced the emergence of the cowpea beetle, while 2.4-4.8 g/1 completely inhibited the production of a new generation of C. maculatus.
Biological activity of leaves, fruits and extract of the African shrubBoscia senegalensis (PERS.) LAM. ex Poir. was evaluated against five stored-grain insects. When added to cowpeas at 2-4% (w/w), fresh ground fruits and leaves caused 80-100% mortality inCallosobruchus maculants (F.) adults and significantly reduced both emergence and damage of the F1 progeny. Acetone fruit extract exhibited a potent fumigant effect onProstephanus truncatus HORN, C.maculatus, andSitotroga cerealella OLIV.; with LT50 values of 3.8, 2.3, and below 1.5 hr, respectively. LC50 determination forB. senegalensis fruits and leaves as well as pure methylisothiocyanate (MITC) onTribolium castaneum HERBST,Sitophilus zeamais MOTSCH. andC. maculatus showed a differential response of the insects to plant parts or MITC. Quantitative dosage ofBoscia active components and LC50 values obtained for the plant tissues, compared to those of pure molecules, indicate that the biological activity ofB. senegalensis is due to the liberation of MITC from a glucosinolate precursor glucocapparin contained inBoscia fruits and leaves.
Resume-Callosobruchus maculatus (Coleoptera: Bruchidae) ou bruche du niebe est un des ravageurs les plus redoutabies des gralnes de niebe en Afrique tropicale. En zone rurale oil les techniques de conservation des denrees sont rudimentaires, ce ravageur entraine des pertes postrecolte pouvant atteindre 100 % en quelques mois. L'importance des dlgats occasionnes a Justine 1 le dlveloppement de methodes de contr61e efflcaces et applkables en milieu villageois. L'ensemble de ces methodes sont passees en revue et l'applicabilite de chacune d'entre elles est dlscutie. II s'avere que la lutte chimique est inadaptee au monde rural compte tenu de son cout et des dangers lies a son utilisation. Les nombreux travaux effectues sur la resistance varietale ont permis d'identifier des varietes plus ou moins resistantes a ce ravageur; toutefois, ces varietes sont souvent peu inteYessantes du point de vue agronomiques. L'incorporation de cette resistance dans des varietes acceptables n'a pas encore donnl satisfaction. Les methodes physiques de lutte sont souvent insutfisantes pour assurer une protection efficace des stocks et de plus, demandent un £quipement et des connaissances techniques approfondles. Quant a la lutte biologique, bien que prometteuse, elle n'en est encore qu'au stade de recherche. Toutes ces restrictions placent les methodes traditionnelles de lutte parmi les plus efficaces et les plus usitees. Ainsi, l'utilisation de la flore indigene et de ses derives, de substances inertes, le controle de l'humidite et de la temperature, ainsi que 1'application des methodes preventives entrafnent une reduction significative des populations de C. maculatus et done, diminuent les pertes post-recolte.Abstract-Callosobruchus maculatus (Coleoptera: Bruchidae), commonly known as the cowpea seed beetle, is the most important pest of stored cowpea in tropical Africa. In rural area where preservation techniques and facilities are limited, it causes post-harvest weight and quality losses. The importance of damages which can reach 100% in a few months justifies the development of effective and appropriate control methods in the villages. All these control methods and their applications are discussed in this paper. Chemical control is inappropriate at farm level, because of its cost and hazards. The many studiesconducted on varietal resistance have enabled identification of varieties that are more or less resistant to this pest; however, the varieties are often of little Interest from the agronomic point of view. The incorporation of that resistance in cultivated varieties Is hi progress. The physical control methods are inadequate because their application requires equipment and technical knowledge which are not found in rural areas. Biological control is an attractive alternative but is still at an experimental stage. AU these limitations support promotion of traditional control methods. Among them, the use of inert substances as well as indigenous plants or their by-products have given, in many cases, a satisfactory control of C. ma...
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