Current state of beech bark necrotic disease in Southern Poland

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The degree of the beech bark necrotic disease was evaluated in three selected localities in southern Poland, in different orographic complexes, Beskid Sądecki, Beskid Niski, and Bieszczady. The degree is expressed by means of the stem necrotising index (I<sub>SN</sub> ), crowns necrotising index (I<sub>CN</sub> ), and whole tree necrotising index (I<sub>NWT</sub> ). The values of the indices laid in the following limits: I<sub>SN</sub> 0.73–0.84%, I<sub>CN</sub> 0.12%–0.51%, and I<sub>NWT</sub> 0.84%–0.90%. The current status of the beech necrotic disease in Southern Poland can be considered as favourable. The values of I<sub>SN</sub> recorded in Southern Poland were lower by 30% than the average I<sub>SN</sub> for whole Slovakia. We also recorded the frequency of selected insect pests (<I>Bucculatrix ulmella</I> Zeller, <I>Cryptococcus fagi</I> Bärensp., and <I>Ectoedemia liebwerdella</I> Zimm.), which act in the beech stands as vectors of the necrotic disease. With <I>C. fagi</I>, we recorded a high frequency reaching even 100%. In contrast, we did not at all observe the occurrence of <I>B. ulmella and <I>E. liebwerdella</I>, which are common in the beech stands in Slovakia, as well as in Hungary, Romania, and Bulgaria. In the localities studied, we recorded the occurrence of two species of parasitic fungi of the genus <I>Nectria</I> (Fr.) Fr. causing the beech bark necrotic disease, viz. <I>Nectria cosmariospora</I> Ces et De Not. and <I>N. galligena</I> Bres. ex Strasser.