Diseases of Vegetables 



1327 



CABBAGE 



Black Rot (Pseudomonas Oam- 

 pestrisl&TW. Smith). This disease 

 is readily distinguished by the 

 presence of brown or black veins 

 in leaves and cross sections of leaf 

 stalks and plant stems. Badly 

 affected plants are stunted and 

 many of the lower leaves may drop 

 off. The disease originates from 

 the presence of a parasitic bacte- 

 rium either on the seed or in the 

 soil. All danger of disease from 

 seed is removed by soaking for fif- 

 teen minutes in a solution of cor- 

 rosive sublimate, one ounce dis- 

 solved in seven gallons of water, or 

 in formaldehyde, one pint to thirty 

 gallons of water. Susceptible 

 crops should not be grown on soil 

 where the disease has occurred 

 until a few years have elapsed. 

 Cauliflower, rape, kale, turnips, 

 wild mustard and other cruciferous 

 plants are also susceptible. FlG - 384.- Bean Blight 



Club Boot (Plasmodiophora brassicae Wor.), Fig. 385. Un- 

 sightly swellings occur on the roots of cabbage, cauliflower, tur- 

 nips, radishes, shepards purse, wild mustard and other re- 

 lated plants. The causal parasite lives in the soil. It is best 

 controlled by rotating crops so that a susceptible crop is grown 

 on a given field only every fourth to seventh year, but in the 

 meantime the field must be kept free from weeds on account of the 

 susceptibility of many weeds. If infested soil must be used apply 

 lime at the rate of three to five tons per acre. Apply and harrow 

 into the soil the fall before planting, or better, a year or two 

 before. 



