Extremely common. I saw tens of these larvae everywhere i looked. Many of them were moving up and down spruce trunks, looking for new hosts to defoliate. The numbers of males coming to my lights was quikly increasing since 2005. In 2008 at one point half the moths attracted to light were Orgyia pseudotsugata males. In 2009 the tree landscape in southern interior of BC looked rather sad, with pine trees killed by Mountain pine beetles and Douglas-fir and spruce trees defoliated by Douglas-fir tussock moth. I reared many larvae and they were all healthy, suggesting the outbreak was in its early stages.