Cowpea is a vegetable that contributes to food security in Guinea. Despite its importance, more than 30% of its production is lost between harvesting, storage and consumption. The main cowpea pest is Callosobruchus ma...Cowpea is a vegetable that contributes to food security in Guinea. Despite its importance, more than 30% of its production is lost between harvesting, storage and consumption. The main cowpea pest is Callosobruchus maculatus. The commonly used control strategy is essentially based on chemicals whose use is toxic, expensive and restrictive. In the search for alternatives to chemical control, this work was undertaken to evaluate the insecticidal potential of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots. Powder toxicity and insecticidal efficacy tests were performed separately on groups of 20 Callosobruchus maculatus using 3 doses of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots in jars each containing 100 g cowpea. The mortality of Callosobruchus maculatus and the impact of powders were noted respectively for 96 h and 4 months after infestation. The germination capacity of the treated seeds was assessed at the start of the study. Doses of 1 and 8 g of Ageratum conyzoides leaf powders and Securidaca longepedunculata roots were applied respectively to every 100 g of cowpea and led to 100% mortality of Callosobruchus maculatus. At these same doses, more than half of the treated seeds were attacked during the 4 months of storage. Germination tests have shown that powders of Ageratum conyzoides leaves and roots of Securidaca longepedunculata have no negative effect on the germination power of cowpea seeds. Therefore, they could be considered as excellent bio-insecticides that socio-professional strata (farmers and warehouse workers) can use in the fight against cowpea insects intended for storage.展开更多
As part of the determination of the possible impact of human activities on surface waters, case of Lake Sonfonia, six sampling sites were selected according to their solicitation by the population and their exposure t...As part of the determination of the possible impact of human activities on surface waters, case of Lake Sonfonia, six sampling sites were selected according to their solicitation by the population and their exposure to probable sources of pollution. The objective of this work is to monitor the physico-chemical quality of the waters of Lake Sonfonia during the low water level (March) and during the flood period (August) of the year 2021. Two sampling campaigns of water were carried out in dry weather and two others in cold weather. Parameters such as temperature, pH, EC (Electrical Conductivity), dissolved oxygen, TDS (Total Dissolved Solids) were measured in situ. Suspended matter, phosphate, nitrate, nitrite, sulphates, total iron, COD (Chemical Oxygen Demand) were measured in the laboratory by the colorimetric method. Stata 15 software was applied for the statistical analysis of the data and the correlation test between the parameters gave highly significant correlations. It has been noted that the situation is not very good and that this pollution comes mainly from human activities.展开更多
文摘Cowpea is a vegetable that contributes to food security in Guinea. Despite its importance, more than 30% of its production is lost between harvesting, storage and consumption. The main cowpea pest is Callosobruchus maculatus. The commonly used control strategy is essentially based on chemicals whose use is toxic, expensive and restrictive. In the search for alternatives to chemical control, this work was undertaken to evaluate the insecticidal potential of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots. Powder toxicity and insecticidal efficacy tests were performed separately on groups of 20 Callosobruchus maculatus using 3 doses of Ageratum conyzoid leaf powders and Securidaca longepedunculata roots in jars each containing 100 g cowpea. The mortality of Callosobruchus maculatus and the impact of powders were noted respectively for 96 h and 4 months after infestation. The germination capacity of the treated seeds was assessed at the start of the study. Doses of 1 and 8 g of Ageratum conyzoides leaf powders and Securidaca longepedunculata roots were applied respectively to every 100 g of cowpea and led to 100% mortality of Callosobruchus maculatus. At these same doses, more than half of the treated seeds were attacked during the 4 months of storage. Germination tests have shown that powders of Ageratum conyzoides leaves and roots of Securidaca longepedunculata have no negative effect on the germination power of cowpea seeds. Therefore, they could be considered as excellent bio-insecticides that socio-professional strata (farmers and warehouse workers) can use in the fight against cowpea insects intended for storage.
文摘As part of the determination of the possible impact of human activities on surface waters, case of Lake Sonfonia, six sampling sites were selected according to their solicitation by the population and their exposure to probable sources of pollution. The objective of this work is to monitor the physico-chemical quality of the waters of Lake Sonfonia during the low water level (March) and during the flood period (August) of the year 2021. Two sampling campaigns of water were carried out in dry weather and two others in cold weather. Parameters such as temperature, pH, EC (Electrical Conductivity), dissolved oxygen, TDS (Total Dissolved Solids) were measured in situ. Suspended matter, phosphate, nitrate, nitrite, sulphates, total iron, COD (Chemical Oxygen Demand) were measured in the laboratory by the colorimetric method. Stata 15 software was applied for the statistical analysis of the data and the correlation test between the parameters gave highly significant correlations. It has been noted that the situation is not very good and that this pollution comes mainly from human activities.
