Integrated Management of Aspergillus flavus and Aflatoxin Contamination in Groundnut Using Organic Amendments and Trichoderma harzianum

Aflatoxin contamination caused by Aspergillus flavus is a serious constraint in groundnut production, particularly under hot and drought-prone conditions. In the present study, A. flavus isolates collected from groundnut-growing areas of northern Karnataka were characterized using morphological and molecular approaches and managed through integrated field and post-harvest strategies. Morphologically, the fungus produced initially whitish colonies on potato dextrose agar that later turned yellowish-green with typical biseriate conidiophores and globose vesicles. Molecular identification using ITS rRNA gene sequencing (~600 bp) and phylogenetic analysis confirmed the Dharwad isolate as A. flavus with high bootstrap support (97–98%). Field evaluation during summer 2021–22 revealed that application of vermicompost @ 1.0 t ha⁻¹ combined with seed treatment using Trichoderma harzianum (IOF) @ 10 g kg⁻¹ seed significantly improved plant growth and yield, recording the highest plant height (34.07 cm at 90 DAS) and pod yield (31.02 q ha⁻¹). Aflatoxin B₁ estimation by ELISA showed non-detectable levels in treatments involving T. harzianum, whereas untreated control recorded the highest contamination. Post-harvest in vitro studies further confirmed superior seed quality, with maximum germination (96.33%), higher seed vigour, and a 69.36% reduction in A. flavus infection over control in the integrated treatment. Overall, the study demonstrates that combined application of organic amendments and biological seed treatment offers an effective, eco-friendly approach for managing A. flavus infection, enhancing yield, and minimizing aflatoxin contamination in groundnut.