a squirrel keeps stealing fruit from my tree. how do you stop him?

I've got a .308 with a scope, it would be overkill, but effective ...........

added:  No, but I know where I can borrow one ........................

Kick him in his nuts. As far as "stealing" I do not think that a squirrel knows the concept.

repeller

You can't stop a squirrel from eating fruit from your tree. I guess you could trap it and relocate it, but you can't legally kill it.

If you don't sell them 

Let him steal

Call the squirrel police and have him arrested, lol.

There isn't much you can do about it, You could leave a few nuts at the bottom of the tree and hope he eats that and leaves the fruit alone.

I will loan you some of our neighborhood tomcats.   They are the feline hit men around here.