Molluscicidal effects of Persicaria senegalensis on terrestrial snails Cornu aspersum in South Africa

Abstract

Cornu aspersum is an invasive terrestrial snail pest of the family Helicidae. In South Africa, where the snail causes significant crop losses in viticulture areas, synthetic molluscicides are used to control them. However, the latter negatively affects both those who apply it and the non-targeted organisms. Persicaria senegalensis, a plant in the family Polyganeaceae, has demonstrated molluscicidal properties against aquatic snails. The present researchers conducted a quantitative analysis of the total saponin content of the leaves, flowers, stems and roots of P. senegalensis. We evaluated the plant’s molluscicidal properties against C. aspersum using the contact assay method over a period of 24 hours. The total saponin content of P. senegalensis’s methanolic leaf, flower, stem and root extracts was found to be 254.42 ± 0.55, 188.53 ± 0.83, 155.19 ± 0.55 and 68.27 ± 0.79 mg DE/mg, respectively. The standard error LD₅₀ of methanol leaf, flower, stem and root extracts against C. aspersum were determined at 549.54 ± 158.49, 758.58 ± 107.15, 1778.78 ± 114.81 and 1819.70 ± 346.73, respectively. The mortality rate of snails exposed to doses of methanolic extracts of P. senegalensis leaves increased with increasing concentrations. P. senegalensis therefore, contains high concentrations of total saponins and molluscicidal properties against C. aspersum.