Control Water regularly, improve the organic content of the soil before planting and do not lime just prior to planting. Resistant varieties include 'Arran Pilot', 'Arran Comet', 'King Edward' and 'Maris Peer'. Blight This is common in warm, muggy seasons. Brown patches appear on the leaves, especially on the tips and the edges. The entire haulm, stem and foliage may die off.
Blight causes brownish patches to develop on the skin and within the flesh of infected tubers.
If weather conditions are likely to encourage blight, spray the foliage with a suitable fungicide before symptoms develop. Clear up all infected plant parts immediately and bin or burn them. Pentland Crown' and 'Estima' show some resistance. Cyst eelworm Two species of eelworm may attack potato roots, significantly reducing yields. The foliage yellows and withers, and plants die prematurely.