REPORT OF THE DEPARTMENT OF BOTANY. 



COMBATING THE BLACK ROT OF CABBAGE 



BY THE REMOVAL OF AFFECTED 



LEAVES.* 



F. C. STEWART and H. A. HARDING. 



SUMMARY. 



Black rot is destructive to cabbage and cauliflower in New York. 

 It is a bacterial disease the chief diagnostic character of which is 

 the appearance of black streaks in the woody portion of the stem and 

 in the leaf-stalks. 



As a preventive of the disease, other investigators have recom- 

 mended the leaf-pulling treatment which consists in removing all 

 affected leaves at frequent intervals. During the past four years 

 the writers have made practical field tests of this treatment and 

 found it to be worthless. 



Each season the experiment field was one acre in extent, one-half 

 being treated and the other half used as a check. During the first 

 three seasons there was not enough black rot to give the treatment 

 a fair trial; but in 1902 there was a moderate attack of the disease. 

 All diseased leaves were carefully removed once a week from July 

 22 to September 16. The treatment not only failed to check the 

 disease but reduced the yield by 5,285 lbs. on one-half acre, or at 

 the rate of 5^ tons per acre. 



*A reprint of Bulletin No. 232. 



