I have some fresh cut pine slabs drying in my basement. A number of small, quarter inch, piles of saw dust showing up all over the slabs . What might be causeing this.

Carpenter ants. They love wood and damp. You have stored them improperly; the pine slabs are not going, could not, dry properly in a basement. You probably brought the ants with the slabs, or the ants were already there.

Tick

Sounds like powder post beatles. Was this a live tree when you cut it? Look for little holes, 1/16"

Yikes. That's a big reason to stick with Kilns. I thought carpenter ants needed a way back to the ground/colony. Beetles Iam not too sure about. Perhaps they were present at cutting but will die out. Some people prefer the look of "wormy" wood as it has more character. I would be concerned however, if the insects are left unchecked and multiply, especially if they have access to the rest of your house.