Olbus oil!!
I was recomended it for a similar wallpaper/carpet chewing problem.
I got a little bottle for about £1.50, I've put drops of it over the carpet and wallpaper -it hasn't stained but I wasn't particually worried about that anyway.
It's brill, Blueberry goes up to the corner, stops and runs away :lol:
I had to do it again after a couple of days as the smell wears off.
I don't mind the smell myself, just when people walk in they say "you still got that cold?" :lol: :lol: