EIGHTEENTH ANNUAL YEAR BOOK— PART VHI 



437 



Control. A field that has grown an infected crop should not be used 

 for cabbage again for many years. It has been shown that yellows 

 will remain alive in the soil for twelve years. On new land it is ad- 

 visible to practice a five-year rotation and under no circumstances 

 should two crops of cabbage be grown on the same land in succession. 



Cabbage plants grown in soil that has 

 been used for growing cabbage sev- 

 eral years should be avoided as they 

 are liable to carry yellows. It is also 

 wise for each grower to propagate his 

 own plants so as to run no chance of 

 introducing this disease. Recently the 

 Wisconsin Experiment station has de- 

 veloped a resistant strain of late cab- 

 bage known as the Hollander. 



GENERAL CONTROL MEASURES 



Seed. In purchasing seed buy the 

 best quality. It should be of uniform 

 size, hard and plump. Cheap seed 

 is often a mixture of early and late 

 varieties. This is often unfortunate 

 for the man who is growing caobage 

 for the early market. In addition to 

 being of good quality and purity as 

 to variety, the seed should be free 

 from diseases. 



Seed treatment. Such diseases as 

 black-rot and black-leg are carried on 

 the seed. The first step, therefore, in 

 successful cabbage growing is to ex- 

 ercise seed treatment. This is very 

 easily done with corrosive sublimate, 

 sold by druggists as bichloride tablets 

 with directions for their use. Less 

 than five cents worth of this poison 

 will suffice to treat a pound of seed, 

 which will grow enough plants for 

 five acres of cabbage. The formula 

 is as follows: 



Corrosive sublimate (bichloride tab- 

 lets) 1 part or i gram. 



Water, 1,000 parts or 1 quart. 

 Soak seed in this solution twenty 

 minutes. 



Fig. 3. Dropping of lower 

 leaves caused by infection 

 with cabbage yellows when 

 plant was about half ma- 

 ture. 



This solution should be made up in 

 a stone jar or a wooden pail because 

 it corrodes metals. Immediately after the seed has been treated spread 

 it on a clean cloth in a warm room to dry quickly. When thoroly dry 

 return the seed to a clean sack, not the same sack from which it was taken 

 before it was treated which may contain spores that will again contami- 

 nate the seed. 



Seed hed soil. An infested bed is often responsible for a crop failure. 

 After the soil has been disinfected it must be planted in clean soil in order 

 ±0 produce healthy plants. It is well to change the seed bed soil every 

 year; but if this is not possible, as is often the case where the beds are 

 large and of a permanent construction, the soil should be sterilized. For 

 this purpose one may use either steam or formaldehyde. 



