Stoyanov, IvanVasileva, PenkaStaykova, TeodoraPopova, TeodoraIvanova, Evgeniya2026-09-162026-09-162026-06-221313-9940https://doi.uni-plovdiv.bg/handle/store/1108Pesticides are widely used synthetic compounds that can persist in the environment and pose significant risks to non-target organisms. Given their potential to induce genetic damage, their genotoxicity can be assessed through mutagenicity testing with suitable model systems. In the present study, the general toxic, cytotoxic, and mutagenic effects of two widely used pesticides, Actellic 50 EC (active substance pirimiphos-methyl) and Rival (active substance propamocarb hydrochloride), were evaluated using Allium cepa L. as a test model. Both formu-lations are used in agricultural practice to control insect pests, storage pests in cereals, and soilborne pathogens. The results demonstrated that Actellic 50 EC (at concentrations of 10 μg/L and 60 μg/L) and Rival (at concentrations of 40 μg/L and 80 μg/L) exerted a clear cytotoxic effect, as evidenced by a reduction in the mitotic index. Their genotoxic potential was confirmed by the induction of a wide spectrum of chromosomal aberrations, including anaphase and telophase bridges, chromosomal fragments, lagging and vagrant chromosomes. In addition, a significant increase in micronuclei frequency was observed, further supporting the genotoxic effects of the tested pesticides. Further studies using additional biological models and molecular genetic approaches are needed to better elucidate the mechanisms underlying the toxic action of these pesticides.enAllium cepapesticidescytotoxicitygenotoxicitymitotic indexchromosomal aberrationsArticle