Comparative cytogenotoxicity and physiological stress endpoints of a Trichoderma asperellum-based biopesticide versus mancozeb and abamectin in plant bioassays.

The global transition toward sustainable agricultural systems has intensified the search for fungal-based biopesticides, such as Trichoderma asperellum, to replace synthetic pesticides. Although considered safer, these products are not biologically inert and may elicit cellular responses in non-target organisms, making comparative ecotoxicological evaluation with conventional pesticides, such as mancozeb and abamectin, essential. This study aimed to evaluate and compare the cytogenotoxic effects, nucleolar alterations, and phytotoxicity of a T. asperellum-based biopesticide in relation to commercial formulations of mancozeb and abamectin. A multi-endpoint experimental design was applied, integrating the Allium cepa bioassay (mitotic index, chromosomal aberrations, micronuclei, AgNOR, plasma membrane integrity, electrolyte leakage, and TTC-based metabolic/mitochondrial activity) with seedling phytotoxicity assays in monocotyledonous (Triticum aestivum, Sorghum bicolor) and dicotyledonous (Raphanus sativus, Lactuca sativa) species. Treatments were tested at label-based concentrations: 2.0 g L-1 T-Protec® (0.07 g a.i. L-1), 13 g L-1 Manzate WG® (9.75 g a.i. L-1 mancozeb), and 1 mL L-1 Vertimec 18 EC® (0.018 g a.i. L-1 abamectin), under continuous exposure (A. cepa for 92 h; seedlings for 72 h for root assessment and 96 h for shoot assessment). Although all treatments significantly reduced the mitotic index and altered membrane integrity, toxicity patterns diverged considerably. The T. asperellum-based biopesticide showed lower genotoxicity, absence of micronucleus induction, and preservation of mitochondrial activity. In contrast, mancozeb and abamectin induced chromosomal anomalies and dysregulated the cell-cycle, reduced mitochondrial activity, and inhibited root and shoot development in the tested seedlings. Overall, despite inducing measurable cellular responses, the biopesticide showed substantially lower cytogenotoxicity and phytotoxicity than conventional synthetic pesticides, potentially making it a safer alternative.