I have a 2-story barn built with Hickory & oak from trees on our property. No doubt there were powder post beetles in the trees and over the last 7 or 8 years I am seeing signs of their fine dust on the floors. Their holes are very tiny and probably would take many, many years for them to do any structural damage in rough-cut 2x6s, 2x8s,2x10s,2x12s, etc. About 2 years ago I sprayed the ceiling joists with Bora Care but recently we’re again seeing dust on the concrete floor. Did I not spray