Effect of buds manually removal and their damage by large pine weevil (Hylobius abietis L.) on Scots pine seedlings in Siversky Donets river valley

Abstract

Large pine weevil (Hylobius abietis L.) damages different organs of Scots pine (Pinus sylvestris L.) seedlings in unclosed plantations, including foliage, buds, stem bark and roots. Simulated damage of respective organs, particularly debudding is one of the ways to evaluate qualitative and quantitative influence of such damage on tree condition. The aim of research was to evaluate the dependence of Scots pine seedlings mortality and height increment on artificial and large pine weevil caused bud damage. The growth of apical shoots of Scots pine seedlings was registered since the beginning of May to the end of June. Development of new shoots in seedlings with manually bud removal or large pine weevil damage started in beginning of May and continued in July. Mortality of Scots pine seedlings with 20% of lateral buds damaged did not differ from that in undamaged plants. The seedlings with apical and lateral buds manually removed as well as with apical and over 70% lateral buds damaged by large pine weevil have died in the year of treatment or damage. The seedlings with apical buds damaged as well as with apical and over 50% lateral buds damaged died in the 4th year after damage. Removal or damage up to 50% lateral buds did not affect the growth of Scots pine seedlings. Height increment of seedlings with apical buds manually removed or damaged by large pine weevil did not differ significantly in May and June of the year of treatment or damage. In July the height increment was statistically greater in the variant with manually removal of apical bud. Previously suggested scale of Scots pine seedlings bud damage satisfactory reflects the score of large pine weevil injuriousness. We can suggest that height increment in the next years after bud damage does not depend on damage way and intensity but mainly on ecological conditions.

Keywords

• Scots pine (Pinus sylvestris L.)
• unclosed plantations
• apical bud
• lateral buds
• manually bud removal
• large pine weevil (Hylobius abietis L.)
• seedling mortality
• height increment