Investigation of acute toxicity of pirimiphos-methyl (Actellic, 25%EC) on guppy (Poecilia reticulata, Peters, 1859).

Pirimiphos-methyl is a broad spectrum organophosphate insecticide and potential toxic pollutant in aquatic ecosystems. The acute toxicity of Pirimiphos-methyl (Actellic) was investigated using Guppy (Poecilia reticulata) in a 96 h static renewal laboratory bioassay. Based on probit analysis the LC50 was 0.026, 0.024, 0.022 and 0.019 ml L(-1) at 24, 48, 72 and 96 h, respectively. Analysis of Variance (ANOVA) showed that there was significant difference (p < 0.05) in the quantal response (mortality) of P. reticulata to different concentrations of Actellic at 24, 48, 72 and 96 h of exposure. Actellic insecticide is toxic to fish; therefore its indiscriminate use in aquatic environment should be discouraged.