Antifungal Activity of Securidaca longepedunculata and Acacia gourmaensis Hydro-ethanolic Extracts against Three Rice Seed-borne Fungi

Aims: This study was undertaken to investigate the antifungal activities of Securidaca longepedunculata and Acacia gourmaensis bark hydro-ethanolic extract against Fusarium solani, Fusarium moniliforme and Curvularia lunata and to evaluate the percentages of germination and infection of infected rice seeds.

Methods: Different extract concentrations ranging from 0.25, 0.5 and 1% were tested during 15 days using poisoned food technique method for in vitro antifungal activity against above three fungal strains. The same concentrations of extract were used to evaluate in vivo antifungal activity on rice seeds infected by these three fungal strains.

Results: The extract of Securidaca longepedunculata had antifungal effect on Fusarium solani and Fusarium moniliforme and completely inhibited its mycelial growth at all tested concentrations (0.25, 0.5 and 1%). Curvularia lunata mycelial growth was inhibited of 84.7% by 1% Securidaca longepedunculata extract after five days of culture. However, mycelial growth of F. solani, F. moniliforme and C. lunata were increased with increasing concentration of Acacia gourmaensis extract. It has been observed that when Securidaca longepedunculata hydro-ethanolic extract concentration increased up to 1%, seeds germination percentage decreased for all infection. In contrast, the opposite was observed for Acacia gourmaensis extract. Likewise, seeds infection decreased with the highest concentration (1%) of Securidaca longepedunculata for all infection, whereas the opposite was observed with Acacia gourmaensis extract.

Conclusion: This study showed that S. longepedunculata hydro-ethanolic extract has more antifungal activity against seed-borne fungi (F. solani, F. moniliforme and C. lunata) than A. gourmaensis in vitro and in vivo. Results show that Securidaca longepedunculata hydro-ethanolic bark extract can be used as a potential antifungal agent in the management of some rice fungal diseases. Acacia gourmaensis extract, at low concentration, could be used in rice seed treatment to increase seed germination.