Are you talking about spraying the egg masses? or targeting the adults that you see, so they don't lay more eggs?

If you are seeing adults, and eggs, did you look for nymphs?  I would think that targeting the nymphs would be the most effective way to use an insecticide.  You might want to brush up on threshholds, and when to target spraying stink bugs.  My guess is that targeting an insecticide onto egg masses is a waste of time and insecticide.