Stem canker of brassicas, also known as blackleg is the most damaging disease of many Brassicaceae. The disease is caused by Leptosphaeria maculans (Desm.) Ces et de Not. and L. biglobosa sp. nov., Shoemaker & Brun, which coexist in plants and resulting in disease symptoms and decreased yield, quantity and quality of cultivated vegetables and oilseed rape. The paper presents taxonomic relationships between these coexisting pathogen species, describes particular stages of their life cycles, summarizes the differences between the species, and reviews methods for their identification.
The aim of this study was to determine the virulence of H. parviporum genets with known genetic similarity and representing pathogen's population, which infested a part of Norway spruce stand. Genets caused average 47% mortality of spruce seedlings in infection experiment in vitro. The mortality rate varied from 16% to 80%. In infection experiment in vivo the mycelium of H. parviporum caused the wood necrosis on distance from 0.8 to 7.78 mm. 56% of genets of investigating population characterized by high virulence, 22% by average and 22% by low virulence.