COMPARATIVE ASSESSMENT OF TOXICOLOGICAL AND BIOCHEMICAL EFFECTS OF EMAMECTIN BENZOATE ON THE AIR-BREATHING FRESHWATER SNAIL (Biomphalaria alexandrina EHRENBERG) AND ITS COMPETITOR SNAIL SEMINOLE RAMS-HORN (Helisoma duryi WETHERBY)

This study was conducted to assess the selective toxicity of emamectin benzoate (EMB) on the intermediate host for the parasite of schistosomiasis disease, B. alexandrina and its bio-control agent seminole rams-horn (H.duryi) as a non-target organism in relation to schistosomiasis control.Also, the biochemical effects of EMB and the effect on eggs' hatchability of these snails were compared.LC10, LC25, and LC50 for both adult snails were determined.In addition, the effects of the sub-lethal concentrations on glucose, albumin, total protein, total lipids, and steroid sex hormones were determined in homogenated snail tissue.LC50 and LC90 values for B. alexandrina were 3.30 vs 6.12 ppm and for H. duryi were 4.80 and 8.00 ppm, respectively after 24 hrs of exposure.1, 3, and 7 days old eggs of H. duryi exhibited significantly higher percentage of hatchability than those of B. alexandrina when exposed to EMB for 48 hrs.Additionally, eggs of H. duryi displayed significantly higher values for glucose, albumin, total protein, total lipids, testosterone, and 17-estradiol than B. alexandrina when exposed to sub-lethal concentrations of EMB.It could be concluded that EMB had a highly toxic effect on B. alexandrina if compared to H. duryi.