Wasp nest in wall

I live in Kitchener (Southern Ontario) and we’ve recently discovered a wasp problem in the bulkhead of our kitchen at the beginning of September 2015.  The wasps entered through a crack in the brick from the outside and made their way into the small bulkhead above our kitchen cupboards.  When we first discovered the problem we had 30-50 wasps buzzing around the hole on the outside.  The pest control company came out immediately and hit the hole with a dust product.  By the afternoon not one wasp was on that side of the house.  I have no idea if they left, died or all went back in the hole.  I keep checking the outside a couple of times a day and never see a wasp go in or out.  But we can hear them sometimes pecking or buzzing in the bulkhead.  Daily we find at least 1 or 2 wasps in our kitchen now.  They are very slow moving and groggy (not flying usually) so they are easy to kill and dispose of.  I’ve been told by the pest control company to leave the nest alone, don’t plug the hole till November or December and maybe in November have a contractor open up the drywall in the bulkhead to clean it out.  Also the winter here in Southern Ontario will kill them eventually.  My concerns and questions are is this a good strategy?  My thought is to open up that bulkhead now and get them out.  I also don’t want young queens to hatch now and make a new home in another part of the wall.  These wasps are obviously finding new ways into the house as we keep finding them in the kitchen so my fear is they are now throughout my walls.  Should I just wait till the cold comes to kill them off and then have a contractor open my bulkhead and clean out the nest?  I’m finding it hard to sleep at night knowing that these things could be anywhere in my house now.  I really need to get them out and fast. Any advice you can give would be greatly appreciated. Thank you, Charles

All of the wasps in the nest will die. This year’s nests will not be occupied again.  Only some fertilized queens will survive over winter if they find shelter and they will seek new places to build nests in the spring. You can ignore the nest in your bulkhead but you should stuff steel wool in the cracks and holes in the exterior wall.