Hi, we have a mid sized pine that has quickly died over the last week. We think it might be some type of bark beetle because of numerous small holes in the trunk, a lot of saw-dust-like plugs at the base, and all the needles have turned brown. Also looking, the pine next to it (another mid-sized) looks to be the tree the adult beetles emerged from (larger holes, lots of sap globs) even though that tree is still alive. Unfortunately, we have two large pines directly next to the infected one, and 5 more large ones on the other side of the yard (80 feet away). We will obviously remove the two infected trees as soon as possible, but what else can we do to prevent the spread?