This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
As already noted, there is no variety of potato on the market which is not more or less susceptible to the disease, though undoubtedly some varieties show much greater capacity for resisting the disease than others. It is also a notorious fact that many of the new varieties of potatoes which have been put on the market within the last few years at fabulous prices, as being practically immune against the disease, have proved to be quite as liable to succumb to the attack of the dreaded fungus as any of the well-proved standard varieties which have been before the public for a dozen years or more. Judging from the experience of the past century, it is not at all likely that a potato of good quality that will be disease-proof for any considerable number of years will ever be brought out.
It was reported from France last year that, after many unsuccessful efforts, a cross between the cultivated potato and the wild potato - Solanum Commersoni - had been brought out and gave every promise of high disease-resisting power, but that it was not well adapted for table use, as its cooking quality left much to be desired. It seems clear enough, therefore, that growers need not rush wildly after any so-called disease-proof new variety for protection against the Phytoph-thora infestans, but that they should follow the lead of common sense and science in the prevention of the disease.
Planting good-sized tubers, whose first sprouts have been carefully preserved, is a most important matter in the way of maintaining the constitutional vigor of the plant. As a matter of course also, preference should be given to those varieties which show the greatest capacity for resisting the disease - that is to say, if their cropping powers and cooking qualities are up to the mark. For those who farm in the warmer and earlier climate south of the Borders, it is also a most important fact, as was urged upon the attention of growers seventy years ago, that seed potatoes should be brought from a colder and later climate than that in which they are to be planted. Seed tubers that have been harvested before being fully ripened are also to be preferred."