Initial In Vitro Assessment of the Antifungal Activity of Aqueous Extracts from Three Invasive Plant Species

Abstract

The development of new, safe, and effective methods of managing fungal pathogens is required. This study was conducted to perform an initial in vitro assessment of the antifungal activity of water-based plant extracts from three plants which are invasive in Egypt: Prosopis juliflora, Ipomoea carnea, and Leucaena leucocephala. These extracts were tested against three pathogenic fungi species that cause high crop losses in Egypt: Fusarium solani, Alternaria solani, and Colletotrichum circinans. Three extract concentrations, 10%, 20%, and 30%, were tested using a completely randomized design, with three replicates per treatment. Antifungal activity was determined based on the effects of plant extracts on fungal radial growth inhibition, average daily growth of fungi, spore formation, spore germination, and total biomass. Inhibition of the growth of fungal strains increased with increasing plant extract concentration, with the highest inhibitory rate at the 30% extract concentration. In addition, spore density, spore germination, and total biomass decreased significantly with increasing extract concentration. The three fungal pathogens differed in their inhibition and their response to these plant extracts. Prosopis juliflora had the highest inhibitory effect on the three fungal pathogens, compared to the extracts from the other two invasive plants. The results of this feasibility study indicate that P. juliflora extracts have high antifungal activity and follow-up in vivo assays should be conducted to determine their efficacy in the safe and sustainable management of these and other fungal pathogens.