Andrejeva O. Peculiarities of pine sawflies distribution and consequences of their influence on forest stands of the Central Polissya

Dissertation is devoted to study of peculiarities of distribution of Diprion pini L. and Neodiprion sertifer Geoffr. outbreaks in the forests of Central Polissya, their impact on sanitary condition of pine stands. It was proved, that sanitary condition of pine stands more worsens in Diprion pini foci, than in Neodiprion sertifer foci, and depends on crown damage level and age of the stands. The trees with crown damage none the less 80 % decline without action of stem pests. Peculiarities of renewal of radial increment of trees in the foci of pine sawflies are investigated depending on stand age, growth class of trees and defoliation level. For the first time for Polissya, numerical score of attractiveness of forest plots was used for determination of list of forest plots, where first-priority survey of pine sawflies must be carried out, on the example of three forestries of SE "Jemilchinske FE" and six forestries of SE "Malinske FE". Critical density of Neodiprion sertifer cocoons for forest protection measures planning is evaluated for Central Polissya.