Cytisus spp. - new host plant for Phytophthora cryptogea in Poland.

Summary Phytophthora cryptogea was isolated from the most of scotch broom (Cytisus spp.) with symptoms of growth inhibition, yellowing of shoots, stem base and root rot. Additionally, the species was also detected in substratum taken from affected plants. In laboratory trials, the isolate from the rotted stem base of Cytisus decumbens, used for inoculation of stem parts and roots, colonised tissues of 6 species and cultivars of scotch broom. Necrosis spread about twice faster on inoculated stem parts than on roots. In greenhouse trial the species colonized 3 scotch broom cultivars and necrosis spread 2 mm/24 hours whereas on Zeelandia cultivar about 3.5 mm/24 hours.