Illustration of antagonist test by dual culture technique of Hypoxlon spp. and Hymenoscyphus fraxineus on barley-malt agar in 9-cm diam. plates A dual culture of H. rubiginosum (MUCL 47152) against Hym. fraxineus (STMA 18166) after 1 wk of incubation B dual culture of H. rubiginosum (MUCL 47152) against Hym. fraxineus (STMA 18166) after 2 wk of incubation C dual culture of H. rubiginosum (MUCL 47152) against Hym. fraxineus (STMA 18166) after 3 wk of incubation D dual culture of H. rubiginosum (MUCL 47152) against Hym. fraxineus (STMA 18166) after 4 wk of incubation E–H (Hypoxylon aff. rubiginosum MUCL 57724) against Hym. fraxineus after 1, 2, 3, 4 wk I–L H. texense (DSM 107933) against Hym. fraxineus after 1, 2, 3, 4 wk M–P H. guilanense (MUCL 57726) against Hym. fraxineus after 1, 2, 3, 4 wk.