FIGURE 2.

Induction of resin terpenes in spruce bark after Endoconidiophora polonica infection. The concentrations of the major resin monoterpenes (upper panel), sesquiterpenes (middle panel), and diterpenes (lower panel) were quantified by GC-FID analysis of bark tissue harvested before and 14 days after infection with E. polonica. Trees investigated: (1) were from a stand with a history of previous bark beetle attack, but no current attack (PA), (2) were under current attack, but had no previous history of attack (CA), or (3) had no previous nor current attack (NA). Data are means ± SE of measurements from 6 to 19 biological replicates; exact numbers are given in the Section “Materials and Methods.” Statistical values for individual compounds are given in Supplementary Tables 2, 3.