Crude extracts of Drimys winteri bark to inhibit growth of Gaeumannomyces graminis var. tritici

the aim of this study was to assess the effect of drimys winteri j.r. forst. & g. forst. bark and its extracts, obtained sequentially with n-hexane, acetone, and methanol, against gaeumannomyces graminis var. tritici (ggt). ground bark of d. winteri was mixed with potato dextrose agar growth media at concentrations of 250, 500, 1000, 2000, and 4000 mg l-1 in petri plates. each extract was mixed at concentrations of 100, 200, 400, and 800 mg l-1. petri plates were inoculated in the center with a 5-mm mycelium disk and were incubated at 24 ± 1 oc. daily measurements of mycelium radial growth were taken to determine growth rate and growth inhibition (%). a ground bark concentration of 978 mg l-1 was needed to inhibit ggt growth by 50%, while extracts obtained with n-hexane and acetone only required 198 and 234 mg l-1, respectively. the methanol extract only inhibited ggt growth by 33% when tested at the highest concentration. in conclusion, ground bark and crude extracts, obtained sequentially with n-hexane, acetone, and methanol, from d. winteri bark inhibit ggt growth when applied in vitro. the n-hexane extract showed the highest inhibitory growth activity.