Tobacco plants growing and no bugs! "Passive pesticide" or "bug bodyguard" in a greenhouse?

Anyone have experience with this?  I grew  "thousand year old tobacco" to try using it later as an experimental pesticide  this year but I missed a few tobacco plants when I transplanted them out.  I didn't need the space right away.   The ones in the greenhouse of course grew quicker and are now in flower.  My greenhouse doesn't have much ventilation but it certainly isn't insect proof.  I'm curious if anyone has used tobacco as a companion plant in greenhouses because there are no bugs in the greenhouse now!    It's weird.  Maybe the plants excrete some nicotine or other foul chemicals into the air?  I was planning to kill off the tobacco because of the risk from viruses going to my tomatoes, peppers and eggplants but I procrastinated (as usual). Maybe it was a good thing.
Brian