Suvák, M. 1999 [Distribution of beech scale (Cryptococcus fagi Barensp.) in beech forest stands.] Rozsirenie cervca bukoveho (Cryptococcus fagi Barensp.) v bukovych porastoch.. Acta Facultatis Forestalis Zvolen 40(1998): 73-83.
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Notes: Information is presented on beech scale (Cryptococcus fagi [C. fagisuga]) and its occurrence in beech [Fagus sylvatica] stands in Slovakia, including factors influencing the population density and distribution of the insect pest. The most important primary factor seems to be the chemical composition of beech bark tissue. This factor is reflected in visible growth characteristics of tree. Examples are given of the variability and distribution of beech scale in 2 beech stands (in the Stagiar and Bien valleys near Zvolen) where these characteristics were observed in association with the distribution of diameter at breast height (dbh). Two methods of evaluation of degree of infestation of beech trees and whole stands were used. The first method was direct counting of colonies of beech scale and enumerations of degree of infestation as density of beech scale colonies over an area of 1 dm2. The second method was visual assessment of degree of infestation classified into one of 5 categories. High variability of infestation was found in trees of both stands. A relationship between beech scale density and dbh was found only where there was a close relationships between the chemical composition of bark tissues and tree diameter.
