Our home is sided with plywood and stained. No problem with the stain but the plywood is grooved vertically on 4 inch centers. Here and there this grooving exposes a void in the sub layer. This wouldn't be a problem either except insects enter the voids thru the grooves and the small downy woodpecker knows they're there. The result is a long line of holes matching the horizontal void. What to do? If I fill the holes I'm sure those areas will not match very well when I restain the house. Any ideas?