Fumigation efficacy and mechanistic insights: the role of natural fumigants in combating aflatoxin contamination in post-harvest sorghum and pearl millet

Aflatoxin contamination is a serious threat affecting agricultural commodities in storage conditions all over the world. In current investigation work, the combination efficacy of natural fumigants such as terpinen-4-ol: cuminaldehyde and terpinen-4-ol: linalool on growth of the aflatoxigenic fungi Aspergillus flavus and Aspergillus parasiticus are assessed. Chemical characterisation using GC-MS of natural fumigant, the A9 combination showed signature peaks of terpinen-4-ol (39%) and cuminaldehyde (54.59%) which effectively prevented the fungal growth and aflatoxin production in both Aspergillus species. Dose-dependent assay indicated a significant antifungal activity at 7.5 and 10 μL with a complete reduction of aflatoxins. Further, A9 combination treatment showed a decrease of ergosterol biosynthesis, plasma membrane damage and oxidative stress in fungal mycelium. Thereafter, in sorghum and pearl millet the fumigation with A9 combination effectively inhibited fungal proliferation and reduced aflatoxins. Conclusively, the study emphasises the use of natural biofumigant combinations in mitigating the aflatoxin contamination.