Abstract Description

Alternaria species cause diseases in many economically important crops which result in economic losses, affecting human and animal health. Alternaria alternata causes black point disease in wheat which takes over its spike, resulting in its black or brown discolouration. The disease is managed by using clean, certified wheat seeds, chemical fungicide treatments, and crop waste management. However, chemical fungicides pose health risks if not properly managed. This study examines the effect of Moringa oleifera leaf extracts on A. alternata. A. alternata was isolated from diseased common wheat (Triticum aestivum) on potato dextrose agar (PDA) and identified using ITS, AaltFor and AaltRev primers. The M. oleifera leaf extract was prepared by using water (MLWE) and leaf powder. Phytochemical analysis of the extracts was conducted with quantitative assays such as the determination of total phenol, flavonoid, alkaloids, saponins, and tannins. The percentage mycelial growth inhibition was determined by growing A. alternata on infused potato dextrose agar (PDA) plates. MWLE infused potato dextrose broth (PDB) cultures were prepared, to report on the reduction of mycelia and spores. The fungus was tested with the extract at different concentrations (10mg/ml, 25mg/ml, 50mg/ml, 75mg/ml, 100mg/ml). The change in antioxidant activity of A. alternata was tested with biochemical assays. The change in mycelial structure was visualised with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Preliminary results show concentrations of phytochemical compounds of the aqueous extracts, mycelial growth inhibition on plates, reduction in total dry mass of fungus, morphological and structural changes in the spores and mycelia of fungi grown in infused broth. M, oleifera leaf extracts can be used as sustainable and cost-effective alternatives in the control of A. alternata on wheat crops.