With a view to developing a strategy for the integrated management of pests associated with cereals in stock in Kivu in the Democratic Republic of Congo, the insecticidal activity of the six plants (M. Lanceolata, S. Syzymbrifolium, A. Squamosa, C. citratus O. Basilicum and O. Gratissimum) on the survival of sitophilus weevils infesting maize and rice was studied under controlled conditions.
The extracts mainly the phenol-tannin mixture for the following plants: C. Citratus, O. Basilicum and O. Gratissimum and the flavonoid-terpene mixture for the following plants: M. Lanceolata, S. Syzymbrifolium, A. Squamosa dissolved in 1% ethanol was applied at 0.2; 0.02 and 0.002 g.mL-1. Compared to controls, our extracts significantly affect the survival of weevils, depending on the concentration and duration of exposure.
Corrected mortality ranged from 67% to 90% for extracts of C. Citratus, O. Basilicum and O. Gratissimum; 69% to 100% for extracts of M. Lanceolata, S. Syzymbrifolium, A. Squamosa. Weevils respond to the toxic effects of the tested compounds, with the LD50 ranging from 0.10 to 0.44 and the LD90 from 0.22 to 0.95 gmL-1. It is the extracts of M. Lanceolata, S. Syzymbrifolium, A. Squamosa which proved to be the most toxic compared to the other extracts.
The vinegar is obtained by a double fermentation of two measures of juice of mango with a measure of water in the presence of the yeast Saccharomyces Cerevisiae for the first fermentation and for the second fermentation, the wine obtained in the first fermentation is added to 10 % of its volume by a mother of vinegar containing the bacterium Acetobacter Aceti. The fermentation lasted 47 days. From the microbiological point of view, the elaborate vinegar is exempt from any pathogenic germ. In spite of its relatively low acidity pH approximately 3, its rate of soluble solids brought up approximately 5,4