Abstract

The effect of methanol extract of Adenium obesum on reproduction, hatchability of eggs of Bulinus truncatussnails was studied. In addition, total protein contents and the activities of the transaminases (AST and ALT) and phosphatases (ACP and AKP) enzymes in hemolymph and tissues of snails treated with tested plant were determined. The present results showed that the molluscicidal activity of methanol extract of A. obesum plant was increased as the temperature was increase and the pH 7 was most promising results of the plants tested as molluscicides. It was found that, the effect of continuous exposure (4 week) to LC₂₅ of the tested plant completely inhibited egg production after 2 weeks while LC₁₀ of the tested plant stopped snails’ egg laying after 3 weeks. All tested concentrations induced marked increases in the percentage of abnormal laid eggs compared to controls. The exposure of B. truncatus snails to such plant extract had led to a significant reduction in egg laying production and hatchability of eggs. The activities of the aminotransaminases [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)], acid phosphatase and alkaline phosphatase enzymes increased while protein content showed a decrease in hemolymph and the digestive gland-gonad (DGG) complex of the experimental snails than that of control snails. It was concluded that the application of sublethal concentration of methanol extracts of A. obesum may be helpful in snail control as it interferes with the snails’ biochemistry and physiology.

Key words: Bulinus truncatus snails, Adenium obesum, plant mollucicides, transaminases, phosphatases enzymes.