Two pathogens from the genus Leptosphaeria: Leptosphaeria maculans and Leptosphaeria biglobosa are the cause of stem canker – a damaging disease of oilseed rape in Poland. The fungi belong to  Ascomycetes,  with both sexual and vegetative stages in their life cycle. The fruiting bodies of the teleomorph, called pseudothecia produce ascospores, which are the primary inoculum infecting young plants. The formation of pseudothecia takes place on infected stubble from a previous season’s crop.
Conducive weather conditions lead to ascospore release and development of disease symptoms.  The main goal of the experiments was to evaluate the uniformity of pseudothecia maturation rate within and between the climatic regions as well as the relation between the development of pseudothecia and ascospore release of L. maculans and L. biglobosa. The study was done for three years (2005–2007) at 7 experiment sites located in three climatic regions of central and eastern Poland, with Puławy located centrally on a borderline between these regions. The maturation of pseudothecia was based on the morphology of asci and
ascospores. The monitoring of ascospore density in the air was done using a seven-day volumetric spore trap. We have found that at early maturation stages the differences in pseudothecia maturation were small and did not exceed 2 weeks, but at advanced
maturation stages the highest differences exceeded a month. The temperature profi les in studied locations were highly correlated, but the correlations between the rainfall data were sometimes very low or non existent. The differences in pseudothecial maturation were mainly associated with the quantity of precipitation both before and during the maturation process.  Ascospore release greatly depended on the rate of pseudothecial maturation of
L. maculans and L. biglobosa.