Dry powder and extract of Posidonia australis Hook. F., a species of seagrass, stimulate the germination of the pathogen Plasmodiophora brassicae and control clubroot of Chinese cabbage

The germination of spores of Plasmodiophora brassicae was stimulated by the treatment with the dry powder and extract of Posidonia australis, a species of Seagrass, collected from the coast of southern Australia. The formation of clubroots in Chinese cabbage was prevented by a treatment with the dry powder and extract, attributed to the stimulation of the germination of Plasinodiophora spores, indicating that the preparations are useful to control clubroot.