Preliminary investigations on phenolics as a response of Scots pine phloem to attacks by bark beetles and associated fungi1

Two fungus and one bark beetle species were introduced into Scots pine phloem. The phenolic composition of the induced reaction zone in the phloem, studied by two dimensional thin layer chromatography, greatly differed from that of the uninjured phloem. The concentration of three compounds increased, one of them considerably, while the concentration of four others decreased. These modifications were the same irrespective of the nature of the aggressor.