Evaluation of antifungal plant extracts against cereal and legume seed-borne pathogens for effective management

Abstract

Sri Lanka as an agricultural country needs to manage the seed-borne fungal pathogens that have caused infections and diseases that result in significant crop losses and a decline in yield and productivity. Therefore, it is imperative to apply pathogen management strategies that are environmentally friendly, and economically feasible such as plant extractions, to reduce seed-borne fungi and increase the quality of the seed. This study was aimed at identifying the antifungal efficacy of <italic>Allium sativum</italic>, <italic>Aloe vera</italic>, <italic>Azadirachta indica</italic>, and <italic>Zingiber officinale</italic> extracts and their effective concentrations to control the seed-borne fungal pathogens; <italic>Aspergillus flavus</italic>, <italic>A. niger</italic>, <italic>Orbilia foliicola</italic>, <italic>Rhizopus oryzae</italic>, and <italic>Talaromyces oumae-annae</italic> isolated from <italic>Arachis hypogea</italic>, <italic>Oryza sativa, Vigna radiata,</italic> and <italic>V. sinensis</italic> respectively. Antifungal efficacy was determined by the agar well diffusion method and poisoned food technique. Plant extracts’ effectiveness for seed germination and seed quality was evaluated by pot experiments. <italic>Zingiber officinale</italic> crude extract exhibited the highest antifungal activity against the tested pathogens which was as effective as Captan 50% (WP), a positive control. Further analysis of the results from the pot experiment revealed that <italic>O. sativa</italic>, and <italic>V. radiata</italic> seeds treated with<italic> A. indica</italic>, and<italic> Z. officinale</italic> aqueous extracts showed 100% germination percentage. <italic>Azadirachta indica</italic>, and<italic> Z. officinale</italic> aqueous extracts are the most effective in promoting seed germination and seedling vigor while <italic>A. vera</italic> extract is the least effective extract. Comparing the two different extracts, aqueous extracts significantly promote seed germination and increase seedling vigor.