Have a Kentucky blue grass lawn. Wide bladed grass from surrounding area is moving in, can I kill the wide grass without killing my lawn?

If you are asking about crabgrass, then I would suggest having a look at the following sites.

http://agebb.missouri.edu/hort/meg/a.../v9n3/meg3.htm

Crabgrass in the Lawn

The News Bulletin: Tips for Controlling Your Crabgrass

Preemergent Crabgrass Control Applications - The P&PDL Picture of the Week - Plant & Pest Diagnostic Laboratory, Purdue University