Toxicity of Imidacloprid Against Melipona scutellaris (Latreille, 1811): Preliminary Risk Analysis

Abstract

The study aimed to evaluate the oral toxicity of the pesticide Imidacloprid Nortox 400 SC® to native bees (Melipona scutellaris, L) and assess the potential risk associated with crops treated with this product. Biotest was conducted using eight concentrations with triplicates. The lethal concentration (LC50) was determined through oral exposure, and the oral lethal dose (LD50) was estimated based on dietary consumption values. The hazard quotient (HQ) was then calculated using the LD50 value. The LD50 value for imidacloprid Nortox 400 SC® at 6h was 0.025 μg a.i. bee-1. Regarding the environmental risk to the species, the acute oral HQ exceeded the trigger value by 200 to 480 times across all evaluated crops. Additionally, the risk of product drift exceeded the trigger value within 50 meters of harvest. These results suggest that, during phase 1, it was not possible to dismiss the possibility of foliar spraying affecting M. scutellaris bees.