Mow it or weed-eat it, especially when it is small. Doing this quite a few times will zap its energy and it will not be able to send up new growth at some point, killing the roots.
You can also blow torch it with a torch weeder, doing the same thing, knocking down the top growth.
Fortunately for me I'm one of those not affected by PI (yet!) so I hand pull it. Next time down your way I'll swing by with a mission!
Shoe
