Toxicidad aguda de metomilo en poecilia latipinna (lesueur 1821) (poecilidae)

Methomyl is a chemical compound acetylcholinesterase inhibitor that acts by contact system and is one of the most widely used chemicals such as insecticide-acaricide for control of a wide range of agricultural pests. The following study aims to assess the acute toxicity of methomyl on introduced fish Poecilia latipinna (Lesueur 1821) (Poecilidae) at 2, 4, 6, 8, 24, 48, 72 and 96 h of exposure. Bioassays were carried out with 5 levels and 4 treatments, temperature was 21.8 ° C ± 1, pH 7.34 ± 0.31, conductivity 0.54 mS ± 0.03, and average dissolved solutes in the middle 267.39 mg.L-1. The data obtained during tests were evaluated using the statistical method analytic Probit ver. 1.5. The results of the median Lethal Concentration (LC ) of methomyl on P. latipinna were: 2 h = 13.95 mg IA.L-1, 4 h 50 =10.39 mg IA.L-1, 6 h = 8.12 mg IA.L-1, 8 h = 5.81 mg IA.L-1, 24 h 3.99 mg IA.L-1, 48 h = 2.61 mg IA.L-1, 72 h = 2.24 mg IA.L-1 and finally 96 h = 2.08 IA.L mg-1. At the highest concentration was observed a change of skin color intensity of silver to black.