EN
The results of investigations on infection of P. nigra by Dothistroma septospora in seed plantation of the Miechów Forest District are presented in this paper. Disease symptoms were analized and the infection intensity depending on the needle age and location in the tree crown was estimated. The differences between individual progenies, and between individual plantation plots with respect to the disease intensity were also analized. The danger created for Pinus sylvestris by the inoculum of D. septospora accumulated on P. nigra was pointed out in the discussion.