Well basically if you want to get rid of them there are two options. You can basically just swat them off the tree and then apply an insect killer all over the tree as well. I would recommend using raid and it will get rid of the caterpillars in no time.
The only way to be totally rid of them is to call pest control they will spray them otherwise you have to cut the limb from the tree and burn the worms and their nests.
Calling your local nursery or landscaping specialist would be the best but you could always pick up your own solution at a gardening store, wich may be the most cost effective.