For an approach of Alternaria in potatoes according to the principles of integrated crop protection (IPM) more knowledge of the disease is needed. By means of monitoring of practical plots, field trials, laboratory and greenhouse tests and numerous analyzes, in the seasons of 2013 - '18 a better insight was gained into the occurrence of Alternaria in Flanders. In this way the occurrence of the disease and the risk can be better assessed, which leads to more efficient control. When using fungicides, sufficient attention must be paid to resistance management. Ultimately, all acquired knowledge is used in a decision support advice system for the potato grower.