Fibre flax production in Europe is concentrated in a limited geographical area covering northern France, Belgium and the Netherlands. For about a decade, Verticillium fungal disease has been occurring in the growing region. It is caused by the soil fungus Verticillium dahliae.

Currently, there are no accurate controls. The fungus can survive in the soil for several years even without host plants. Thus, the available growing area decreases over the years. The disease causes yield losses but mainly has a negative effect on the quality of flax fibre.