Effect of two herbicides on some biological and biochemical parameters of Biomphalaria alexandrina.

The herbicides, Butachlor and Fluazifop-p-butyl were evaluated against B. alexandrina and their infection with S. mansoni, as well as against the miracidia and cercariae. The tested herbicides reduced the survival and infection rates of B. alexandrina by 28% and 35.71% for Butachlor and 50% and 64% for Fluazifop-p-butyl, respectively. These herbicides significantly reduced the production and duration of cercairal shedding per infected snails. The mortality rates of miracidia and cercariae were elevated gradually by increasing the sub-lethal concentrations of herbicides being 63% and 62%, respectively, after 6 hours of exposure to 6.5 ppm of Butachlor. The protein, glycogen and lipid contents in the snail Soft tissues were significantly reduced. There was a significant elevation in the levels of acid and alkaline phosphatases in haemolymph of snails exposed to Butachlor, 0.05 and 0.48 u/mg protein, respectively.