High resistance to Verticillium wilt has been recorded in seedling F4328 and the variety Houma. All other varieties under test have shown moderate to high susceptibility to soil-borne inoculum. No direct correlation is apparent between the amount of disease developed from soil-borne inoculum and the extent to which the disease is perpetuated by the invasion of the tubers by the fungus. Susceptible varieties which are capable of readily disseminating the disease by means of mycelium in the tubers include: Irish Cobbler, Sebago, Chippewa, F458 and F426. Economic losses in commercial stands of potatoes grown in Prince Edward Island have been confined to the varieties represented by this class.