526 DISEASES OF CULTIVATED PLANTS 



only be infected during the seedling, or quite early period of 

 growth, hence, if seed-beds for the various kinds of cabbage 

 are properly limed, the plants will grow up free from disease. 



If 





FIG 157. Plasmodiophora brassicae. i, young turnip 

 showing early stage of disease ; 2, cabbage showing clubbed 

 root ; 3, two infected cells from root of cabbage, one con- 

 taining plasmodium, the other crowded with minute spores 

 of the parasite ; 4, three myxamoebae or motile bodies pro- 

 duced by the spores on germination. Figs. 3 and 4 highly 

 mag. 



It will be impossible to stamp out the disease unless proper 

 precautions are taken. In the case of cabbages grown in 



