Insecticidal Activity of the Powders Obtained from the Bauxite Red Mud, Zyzygium aromaticum and Citrus sinensis Peel Extracts on the Conservation of Corn against Sitophilus zeamais: Physicochemical Properties

The remarkable push of technologies increasingly recommends materials for their constructions.Hence the extraction of alumina is for different uses.The exploitation of bauxite pollutes the surrounding areas in this case the discharge of mud wheel.Furthermore,the excessive use of dangerous conventional synthetic insecticides continues to be in circulation in Cameroon despite the known adverse effects.These problems lead us to formulate bio insecticides from rejection of the extraction of alumina and extracts of S.aromaticum and Citrus sinensis which respectively offer us essential oils eugenol and limonene having insecticidal properties against the main insects,pests of corn stocks,Sitophilus zeamais.From the kinetic point of view of the adsorption of the extracts of eugenol,limonene and their association by the red mud,the adsorption curve shows that the Eu/Li mixture(30/70)is better by 0.36 mg/g during the 24 h.The results showed a high toxicity of the Eu-Li binary mixture of ratio 30/70 with respective mortality rates of 95.88%after 8 days of exposure to the concentration of 5 mL/L on the adults of Sitophilus zeamais.The other composites induce an average rate of 80%.The results from the physicochemical analysis of corn before and after treatment with formulated insecticides showed a slight loss in nutritional quality of 14.90%in ash,12.5%in protein,16.14%in lipids and 13.63%in total sugars for 180 days.The powdery formulation from red mud and Eu-Li(30/70)mixture can therefore ensure the protection of corn stocks against Sitophilus zeamais in a farming environment.

Seasonal Contrast of Some Anthropic Pollution Parameters in Water Retention in Mountainous Area under Sahelian Climate: Elementary Dynamics and Space Distribution (Territory of the Mounts Mandara, Cameroon)

In order to understand the origin, the extent and the space distribution of the seasonal anthropic pollution parameters in the water retention located in mountainous area thickly populated and which water resources is intended for the production of drinking water for serving a population of approximately 800,000 inhabitants, two sampling campaigns were carried out for the two seasons of the year known as the dry and rainy season. The samples were then conveyed and analyzed in laboratory. The parameters retained for this study were primarily the physicochemical parameters (pH, conductivity and temperature), measured in situ and second the major anthropic origins anions of (, , and ). The results of the study show that overall the anthropic pollution parameters undergo an important seasonal variation of their concentration between the dry and rainy periods although they remain high in any season compared to the quality standards of natural water of the European Union. Their space distribution within retention remains overall random and is not function of the seasons. However, surrounding areas of the retention and the discharge system of the seasonal rivers (Mayos) which feed it present in rainy season space distributions of concentrations in anions of anthropic origin enumerated above highest.