Interesting photo with all that paper mulch!
Several points about that much mulch:
- Poor circulation to the developing tubers versus soil hilling
- Diffusion into the potato tuber of oxygen for respiration takes place only through lenticels.
- Lenticels are those whitish bumpy areas dotted around the tuber and are pronounced under overly wet or heavy soils, and/or too much mulch.
- Some varieties are sensitive, yea, hypersensitive to poor air exchange.
- With that much vermin pressure you may need more hills to get a fairly good and undamaged crop.
- May need a cat population upwards a herd.
- Potatoes planted near wooded or weedy lots more apt to have vermin.
- You certainly don't have weeds!