Assessment of the early growth of Amazonian forest tree species under exposure to pesticides

The increasing use of pesticides, driven by the global demand for food and energy, often results in environmental concentrations exceeding safety use levels due to indiscriminate use. This study evaluated the impact of cypermethrin, atrazine, glyphosate, and 2,4-D at different concentrations on the initial growth of Amazonian forest tree species. The recommended doses for application of these products or based on the label of these products were: 0.02 l ha⁻¹ of cypermethrin, 4.5 l ha⁻¹ of atrazine, 3 l ha⁻¹ of glyphosate, and 1.5 l ha⁻¹ of 2,4-D. Based on these values, the following concentrations were tested: 1/4, 1/2, recommended, 2 × , and 4 × the recommended dose, along with controls with water and adjuvant Assist Assist® EC. After 30 days, Final Mortality, Collar Diameter, Stem Length, Root Length, Shoot Dry Weight, Root Dry Weight, and Total Dry Weight were evaluated. Considering the species tested H. petraeum exhibited higher sensitivity to cypermethrin and glyphosate, with severe effects observed even at 1/4 of the recommended dose, particularly affecting dry mass. In contrast, E. schomburgkii showed greater sensitivity to atrazine and glyphosate, again with significant impacts on dry mass. Root dry mass emerged as an effective parameter for assessing pesticide toxicity in both species.