Flax (Linum usitatissimum L) yield of stem and seeds and them quality is influenced by a number of harmful diseases but investigation about pathogens in recent years have not been done in Latvia. Each stage of development of disease is important in the pathogen life cycle and requires certain condition. Goal of this study have identify possibilities of the pathogens and were assess disease severity depending on the genotypes on flax in variable environmental conditions. The resistance to the diseases for 24 flax genotypes and standard variety ‘Vega 2’ were evaluated. The field trials have been carried out over the period from 2015 to 2016 at the Research Centre of Priekuli, part of Vilani in Latgale. Disease progress was measured every wee...