Influence of Meteorological Factors on Needle Cast Damage in Young Scots Pine Stands

Abstract

Abstract Climate changes are expected to create favourable conditions for development and spread of diseases. Therefore, the impact of meteorological factors on needle cast damage, and relationship between degree of damage and growth of trees had been assessed in the study. Analysis was carried out in open-pollinated progeny trial of Norupe seed orchard clones, established in the spring of 2006, in Ltd. “Rīgas meži” (LLC “Riga Forests”). In this trial needle cast damage was assessed in three consecutive years using a fivegrade scale, dependent on the level of damages on current year needles. At the end of each growing season a tree height was measured. Plantation was significantly affected by infection average more than 66% of current year damaged by the disease. Significant (p<0.001) correlation was detected between the degree of needle cast damage and tree height increment as well as the tree height. Significant (p<0.001) differences in needle cast infection level as well as tree height and height increment were found also between open-pollinated families. The results suggest a potentially increasing needle cast infection due to predicted increase of temperature and precipitation, as well as the potential to select more resistant families against damages of this disease in tree breeding process.