Physical and chemical characteristics of blue and Engelmann spruce relative to spruce beetle host selection and colonization

•Resin flow was greater in blue spruce.•Bark was thicker and phloem was thinner in blue spruce.•Concentrations of within-phloem terpenes were more than double in blue spruce.•Engelmann spruce foliage emitted greater concentrations of volatile terpenes.•Spruce beetles landed and attempted colonization at higher rates on baited Engelmann spruce than baited blue spruce.