Family Cruciferae 197 



tufts are prevalent in the center of the spots, and are 

 pale brown and sparingly septate. The conidia are 

 long clavate, tapering, straight to curved, many sep- 

 tate, and hyaline to faint smoky color. 



Wilt or Yellows 



Caused by Fusarium conglutinans Woll. 



There is no other cabbage disease that is economi- 

 cally so important as wilt. This trouble is threaten- 

 ing the cabbage industry in many parts of the United 

 States. In the cabbage centers of Ohio and Wiscon- 

 sin, truckers lose so heavily from wilt, that in many 

 sections, the growing of the crop has been made very 

 unprofitable. 



Symptoms. The term ' ' yellows " well describes the 

 disease. Affected seedlings are yellowish and stunted 

 in growth with a tendency to drop their lower leaves 

 at the least touch (fig. 31 g). Such plants when 

 transplanted in the field either die outright or make 

 very slow growth. The symptoms in the older 

 affected plants are the same as on the seedlings. 

 The outer leaves turn yellow and drop off one by one, 

 until a bare stump and top head are left (fig. 31 d). 

 Usually the plant is uniformly attacked ; but the in- 

 fection may be confined to one side. This one-sided 

 check results in the lateral warping and curving of 

 the stems and leaves. Under field conditions, high 

 temperatures are very favorable for the spread and 

 development of yellows. 



The Organism. The best description of Fusarium 



