The present invention relates firstly to the discovery of the previously unknown 24- membered cyclooctadepsipeptides PF1022-V, PF1022-W, XRB-C894, XRB-C942, XRB-C976, XRB-C1010, XRB-C1044, XRB-E922, XRB-E956, XRB-E990, XRB-E1024, XRB-S958, XRB-S992, XRB-S1026, XRB-S1060 (in various isomeric forms) and to the processes for the preparation of the abovementioned cyclooctadepsipeptides by means of the fungal strains from the family Xylariaceae, in particular the genera Rosellinia and Coniolariella, and by means of the mitosporic fungal strains from the groups Fusarium, Beauveria and Verticillium (orders Hypocreales and Phyllachorales), and by means of the enzymatic preparations isolated from these fungal strains, and secondly to the use of these strains for the preparation of the abovementioned novel cyclooctadepsipeptides and to the use of bassianolide and of the abovementioned novel cyclooctadepsipeptides individually or as a mixture, as anthelmintics or endoparasiticides.
