Preliminary studies of inhibitions in Aspergillus flavus with extracts of two lichens and Bentex-T fungicide

Abstract

One ml aqueous concentrations at 0.1, 0.25, 0.5, 1.0, and 5.0 mg/ml of laboratory extracts of Hypogymnia physodes and Ramalina farinacea (Lichens), and Bentex-T, were incorporated separately in a basal broth culture medium inside conical flasks. Mycelial dry weight of Aspergillus flavus, grown on the medium with the extracts of the lichens, was inhibited between 70% - 80% compared to unincorporated control medium. Bentex-T inhibited the A. flavus between 60% - 65%. Sporulation of A. flavus was inhibited more by Bentex-T and the extract of R. farinacea by 60% - 75% than the 29% - 34% caused by H. physodes. Spores of A. flavus in control medium commenced germination after 2 h while it was mostly after 4 h or 6 h in the incorporated media. Inhibition of germination was significant at 5% level with 0.1 and 0.25 mg/ml and highly significant at 1% level with 0.5 to 5.0 mg/ml concentrations of the extracts and Bentex –T. The extract of R. farinacea appeared to be most inhibitory on the germination of the spore.

Key Words: Lichen extracts, fungitoxic, Aspergillus flavus.

African Journal of Biotechnology Vol.3(9) 2004: 468-472