Development and biological evaluation of nanoencapsulated-based pyrethroids with synergists for resistance management of two soybean pests: insights for new insecticide formulations

Applicability of Food Monitoring Data for Assessing Relative Exposure Contributions of Pyrethroids in Retrospective Human Biomonitoring Risk Estimations

The use of pyrethroids is very broad and shows increasing trends. Human biomonitoring studies represent the best approach for realistic risk estimations, but their interpretation requires a tiered approach. A previous HBM4EU study indicated levels in European children groups just around the threshold for concern, requiring further refinement. The main difficulty is that several pyrethroids with different toxicity potencies generate the same urinary metabolites. As diet is the main pyrethroid source for the general population, EU food monitoring data reported by EFSA have been used to estimate the relative contribution of each pyrethroid. The main contributors were cypermethrin for DCCA and 3-PBA and lambda-cyhalothrin for CFMP. Urinary levels predicted from food concentration according to the EFSA diets were mostly within the range of measured levels, except 3-PBA and CFMP levels in children, both below measured levels. The predicted lower levels for 3-PBA can be explained by the very low Fue value, initially proposed as conservative, but that seems to be unrealistic. The discrepancies for CFMP are mostly for the highest percentiles and require further assessments. The refined assessments included the revision of the previously proposed human biomonitoring guidance values for the general population, HBM-GV Gen Pop, following recent toxicological reevaluations, and the estimation of hazard quotients (HQs) for each individual pyrethroid and for the combined exposure to all pyrethroids. All HQs were below 1, indicating no immediate concern, but attention is required, particularly for children, with HQs in the range of 0.2-0.3 for the highly exposed group. The application of probabilistic methods offers assessments at the population level, addressing the variability in exposure and risk and providing relevant information for Public Health impact assessments and risk management prioritization.

Insecticidal activity of extracts of handroanthus impetiginosus on Plutella xylostella (Lepidoptera: plutellidae) larvae

Plutella xylostella is considered the main pest of cabbage in Brazil and the world, causing damage of up to 100%. Thus, this study evaluated the insecticidal activity of extracts obtained from the fruits, seeds, bark, leaves, and flowers of Handroanthus impetiginosus against the diamondback moth, P. xylostella larvae. The seed extract showed the highest mortality (97.0%) compared to the control treatment. The LC50 values indicated that the seed and flower extracts (0.01003 and 0.01288 mg/L respectively) assumed the highest toxicity to P. xylostella larvae after 24 h of exposure. The results of this study indicated that the seeds extract is the most promising toxic extract, with measured mortality of approximately 97.0% for P. xylostella larvae after 144 h of exposure in kale plants. Seed extract showed the best insecticidal activity. Thus, this extract can be applied to develop an insecticide based on H. impetiginosus seed.