I used that too some years ago. In fact, I do not remember seeing the spiders that much. I even put it in the mainsai (when it was down, inside the folds).
Truth is, if you are on your boat quite a bit and keep it really clean, you will get rid of 99% of them. If not, well, not a whole lot you can do.
PS The strip has no smell associated with it. Nice thought langdon.