Potato cyst nematodes (PCN),Globodera rostochiensisandG. pallida, are widespread in the ware potato‐growing areas of the UK. Traditionally they were controlled by rotation but more intensive production methods have increased the PCN threat, especially fromG. pallida. G. rosrochiensishas become less important since cultivars fully resistant to it were introduced but, where both species are present in a mixture, theG. pallidaportion comes to dominate. It is possible to controlG. pallidaas effectively as G.rostochiensisif cultivars partially resistant toG. pallidaare grown with nematicide treatment. Where nematicide is not used, control ofG. pallidais more variable. In some years, some cultivars achieve good control but the results are not consistent. In general,G. pallidahas increased on untreated plots about 5‐fold in trials in the last 3 ye