Pine straw seems to be popular in Texas and other southern areas. (Is that where you garden?)
Presumably, because it's pine, pine straw is acidic. Potatoes like slightly acidic soil, specifically a pH range of 4.8 to 6.0. However, they may not like too much of a good thing.
We suggest that you test your soil's pH and determine whether or not it needs additional acid. Based on that test, you could use pine straw alone or play it safe by adding other mulch materials to the pine straw and so reduce the acidic effect.
We hope this helps. Good luck! Let us know how it goes.