Pathogens present on vegetative organs and seeds of white mustard (Sinapis alba L.) and chinese mustad (Brassica juncea L.)

摘要

The research was conducted in the years 1999-2001. The aim of the research was to determine the health condition of overground parts and seeds of white niuslard ( Sinapis alba L.) cv. Metex and chinese mustard ( Brassica juncea L.) cv. Ma?opolska. In all the years of the research alternaria blight was found on the leaves of white mustard which injury index ranged from 5,6% in 2001 to 17,6% in 200O. The most dangerous disease of chinese mustard also was alternaria blight and its symptoms were found on leaves and siliques. The strongest infection of leaves was in 2000 (50%) and the weakest in 2001 (6,7%). In all the years of the research siliques were rather weak infected (50-8,89%). Besides powdery mildew was found on chinese mustard which injury index ranged from 0,3% in 1999 to 32,3% in 2000. Intensity of diseases was affected generally by the weather conditions. From the seeds of white mustard and chinese mustard were isolated respectively 263 and 137 colonies. Alternaria alternata was the most numerous species which makes respectively 60,9% and 42,3% isolates. Among the fungi pathogenic for white and chinese mustard were also isolated: A. brassicae, Botrytis cinerea and Rhizoctonia solami .