Effect of copper sulphate, certain plants and adjuvants on the snails Biomphalaria alexandrina and Lymnae natalensis and on the zooplankton [Daphnia pulex]

ABSTRACT

The snails Biomphalaria alexandrina and Lymnaea natalensis were exposed to 1/10 LC50 of copper sulphate or of the plants Anagallis arvensis, Calendula micrantha and Ambrosia maritima. The snails were exposed firstly to copper sulphate then to each of the tested plants and vice-versa. The results showed that the pre-exposure of snails to A. arvensis and C. micrantha plants increased the molluscicidal action of copper sulphate against B. alexandrina and L. natalensis where it caused an additive effect. The pre-exposure to A. maritima caused different effects with copper sulphate, where it showed antagonistic effect on B. alexandrina and additive effect on L. natalensis snails. The pre-exposure of snails to copper sulphate increased the molluscicidal action of the tested plants against B. alexandrina and L. natalensis where it caused synergistic effect in case of Anagallis arvensis and Calendula micrantha against L. natalensis and additive effect in the rest of the treatments. Mixing of copper sulphate with each of the tested plants at different ratios caused antagonism in the molluscicidal activity of copper sulphate against B. alexandrina and L. natalensis snails. The addition of each of the following adjuvants; mono-ethylene glycol mono-oleate, mono-ethylene glycol di-oleate, potassium di-hydrogen phosphate and KZ mineral oil to copper sulphate increased the molluscicidal activity of copper sulphate against B. alexandrina, where it caused synergistic effect. In case of L. natalensis, mono-ethylene glycol mono-oleate and mono-ethylene glycol di-oleate caused an additive effect; while, potassium di-hydrogen phosphate and KZ mineral oil induced antagonistic effect. The result of examination of the toxic effect of copper sulphate in combination with each of the tested adjuvant against Daphnia pulex indicated that the treatment of copper sulphate and mono-ethylene glycol di-oleate increases the molluscicidal activity of copper sulphate and at the same time reduces its toxic effect against non-target organisms [Daphnia] and is the best for application