Answer:
shoot them of your property
Really? Shoot them? I wonder if that would hold up in court if someone steps in your yard? Never trust an answer that's not in basic english.
From what I have read so far, if it is posted, and they cross, it is second degree criminal trespass. If you have warned them and they cross, again criminal trespass. If your property isn't posted and you don't say anything, then they can remain?