Is my scotch pine dying or just stressed?

Pine wilt is fast and unmistakable: needles go grey-green, then tan, then brown, and the giveaway is that the dead brown needles stay attached rather than dropping, usually starting on one branch or one side and taking the whole tree the same season. A fresh cut into the trunk of an infected tree yields little or no resin, which is the field test; slow, even, bottom-up thinning is ordinary needle cast or site stress, but branch-by-branch browning in mid-to-late summer means dead, not stressed.