It was determ ined th at m ortality of poplar saplings had been caused by C ytospora cancer (Cytospora clırysosperma “ P ers” F r.) in Ç ankırı K enbağ F orest N ursery, surroundings of Ç ankırı and gardens of certain private and governm ent enterprises. Symptonıs of pathogen on poplar trunks w ere determ ined, m easures of conidia w ere done, and the best feed up media, relations w ith insects by pathogenisity studies and dam age status vvere elucidated. C ertain cultural precautions w ere suggested for soiution waiting producers and governm ent agencies because of the em ergency of the subject.