Inhibition of Aspergillus flavus sporulation and aflatoxin production in stored maize using powdered leaf of botanicals

Subsistence farmers’ fungal control of stored maize using synthetic fungicides is expensive and results in adverse health effects. Hence, the effect of natural and abundantly available neem (Azadirachta indica A. Juss) and lemongrass (Cymbopogon citratus (DC.) Stapf.) leaf powder on aflatoxigenic Aspergillus flavus sporulation and aflatoxin production was evaluated. The study results showed that 5% w/w and 10% w/w neem leaf powder were able to inhibit Aspergillus flavus sporulation by 76.15% and 80.34%, respectively, compared to the control after 30 days of co-storing with maize grain (19% initial moisture content). Whereas, 10% w/w lemongrass leaf powder was able to inhibit Aspergillus flavus sporulation by 53.52% compared to the control after 30 days of co-storing with maize grain (19% initial moisture content). The estimated median effective dose (ED50) of neem leaf powder, which inhibited 50% of A. flavus sporulation in 30-day stored maize with 19% initial moisture content, was 3 g in 100 g of maize grain. Neem leaf powder as low as 5% w/w stored with maize grain for 30 days inhibited aflatoxin production. Thus, mixing powdered leaf of neem (5% w/w) with stored maize grain considerably hinders aflatoxigenic Aspergillus flavus sporulation and aflatoxin production. The study indicated the potential of such natural, inexpensive and safe control methods of maize storage for subsistence farmers.