The yield losses caused by potato cyst nematodes, the variation in tolerance between cultivars, and the principles which control nematode population dynamics are reviewed. The white potato cyst nematode, Globodera pallida, is becoming increasingly important in many countries, both because it is becoming more prevalent and because it is more difficult to control than the golden nematode, Globodera rostochiensis. A number of previously unexploited control strategies may help in the control of G. pallida; these include the use of artificial hatching agents, trap crops, potato cultivars that act as poor hosts, and biocontrol agents. In addition, molecular technology may give rise to exploitable novel resistance mechanisms and will almost certainly provide rapid and accurate diagnostic aids.
