The Potency of Graphitic Carbon Nitride (gC3N4) and Bismuth Sulphide Nanoparticles (Bi2S3) in the Management of Foliar Fungal Pathogens of Maize

Abstract

Maize (Zea mays L.) is the most significant grain crop in South Africa. Despite its importance, the cereal is ravaged by several foliar fungal pathogens, which reduce maize quality and quantity at harvest. Hence, this study investigates the fungi associated with foliar diseases of maize in Molelwane, North-West Province, South Africa. The fungi were isolated, characterized and subjected to in vitro nanoparticle control. Samples of diseased maize leaves were aseptically collected from two maize-growing farms. Fungi associated with the samples were isolated and characterized using standard procedures. Bi2S3 (metal-containing) and gC3N4 (non-metallic carbon-based) nanoparticles were synthesized and used to challenge the pathogens using standard procedures. Foliar fungal pathogens isolated from the diseased maize leaves in this study were characterized as Bipolaris zeicola, Phoma herbarum, Epicoccum nigrum, Alternaria alternata and Fusarium brachygibbosum. Phoma herbarium > A. alternata > B. zeicola > F. brachygibbosum > E. nigrum was the order of percentage fungal inhibition by the nanoparticles. Bi2S3 was more effective against the pathogens at lower concentrations and gC3N4 at higher concentration levels. The two nanoparticle types evaluated in vitro shows potential for managing the foliar fungal pathogens, and this needs to be further validated in field studies.