There are 2 basic ways of gettings worms/bugs in old books. The poor man's way and the one who has a large budget. Let's mention the one for most of us poor folks. It's quite simple and cheap! Take the book, wrap it in about 2 to 3 plastic bags and put it in the freezer for about 3 days. After 3 days, remove the book from freezer, unwrap the plastic's and let it air out for another few days, taking care to leaf through the pages to get rid of any moisture which is not done can cause mildew to start in the book.  If you leaf through the pages, you may see the worms, and if you touch them, they should be "melted", sort of gooey. They are 100% dead! take my word for it!

The other more expensive way is to fumigate it in a University libray which offers this kind of service, a usually expensive one may I add.

I would shun away from spraying the book as the moisture from the spray may cause discoloration and start mildew if the book is not dried properly,