Histopathological and physiological effects of selected agrochemicals on non-target Archachtina marginata
Abstract
The chronic and acute toxicity of the foliar fertilizer, Boost Xtra®and the pesticide, Cypercot® were investigated against the non-target agro ecosystem fauna Archachatina marginata. The results of 96 hours acute toxicity test indicates differential toxicity of both chemicals (LC 50 :Cypercot=74.286, Boost Xtra =250.935) to A. marginata. Based on
the calculated 96hrs LC 50 , Cypercot was found to be approximately three times more toxic than Boost Xtra. Sub-lethal exposure to 1/10 th ,1/100 th and 1/100 th of the LC 50 of Cypercot and Boost Xtra for 28days did not significantly impair growth because weight changes were not significant (p>0.05) although unexposed control snails recorded higher average
weight gain. Histological assessment of the gut and reproductive tract of the mollusc exposed to different sub-lethal concentrations of the agrochemicals indicates that Boost Xtra is much more persistent than Cypercot, causing severe necrosis and sloughing of the gut epithelium at 1/10 th of the LC 50 (55.3ml/L). Cypercot induced no visible lesion in the gonadal epithelium while the sub-lethal exposure to Boost Xtra initiated massive necrosis in the gonadal duct. Sublethal concentrations of both chemicals induced aestivation but this was not always concentration dependent. The importance of these findings are discussed.
the calculated 96hrs LC 50 , Cypercot was found to be approximately three times more toxic than Boost Xtra. Sub-lethal exposure to 1/10 th ,1/100 th and 1/100 th of the LC 50 of Cypercot and Boost Xtra for 28days did not significantly impair growth because weight changes were not significant (p>0.05) although unexposed control snails recorded higher average
weight gain. Histological assessment of the gut and reproductive tract of the mollusc exposed to different sub-lethal concentrations of the agrochemicals indicates that Boost Xtra is much more persistent than Cypercot, causing severe necrosis and sloughing of the gut epithelium at 1/10 th of the LC 50 (55.3ml/L). Cypercot induced no visible lesion in the gonadal epithelium while the sub-lethal exposure to Boost Xtra initiated massive necrosis in the gonadal duct. Sublethal concentrations of both chemicals induced aestivation but this was not always concentration dependent. The importance of these findings are discussed.
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