I'm visiting my parents over the weekend and noticed this white stuff on a few of the pines on their property. I know the tree it is mainly on has been dead for a while, but I'm concerned that it is some type of disease. I saw it on a few of the living trees around it. Is this anything to worry about? What is it?

I can not tell from the picture but my best guess would be either lichen or fungus. They are not what killed the tree and they will not harm the others. Lichen grow on many types of and do no harm, fungus will grow on dead or dying trees and are a natural part of the decomposition process.

I don't know for sure but it could also be the woolly adelgid aphid. They can look like a white fungus from a distance but they also fly around and if you're seeing them on other tree's I would be concerned they have devastated the trees in the Smoky Mountains

I'm thinking lichen like Jay. It wouldn't be the hemlock wooly adelgid because that affects hemlock not pine. There is a pine bark adelgid though. Is it possible to get a closer picture of the white stuff so we can see it properly?