Family Solanacese 331 



first described by Jamieson and WoUenweber.' The 

 trouble is the same as that described by Wilcox" 

 and the causative organism was previously named 

 Fusarium tviierivorum. In poorly ventilated storage 

 houses, bruised potatoes dry rot (fig. 63 a), the entire 

 content of the tuber turning into a powdery mass. 

 The disease does not attack growing plants in the 

 field nor unbruised tubers. 



There are numerous other species of Fusaria which 

 are capable of producing a rot on tubers through a 

 wotmd. Sherbakoff * mentions twenty-eight of them 

 which may .produce a rot on stored potatoes. 



Rosette or Russet Scab 



Caused by Cortidum vagum B. and C. var. solani 

 Burt. 



Rosette, although generally distributed, is more 

 prevalent in the Eastern States. The disease is 

 often very serious, and causes great money losses. 

 The trouble attacks the tuber as weU as the foot of 

 the stem. 



Symptoms. On the tubers the disease is recognized 

 as superficial dark brown sclerotia varying in size from 

 that of a mustard seed to that of a vetch (fig. 63 c). 



- J Jamieson, C. C, and WoUenweber, H. W., Jour. Wash. Acad. 



Sci., 2 : I4&-I52i 1912. 



^ WDcox, E. M., et al., Nebraska Agr. Expt. Sta. Research Bui. 

 I : 1-88, 1913. 



3 Sherbakoff, C. D., New York (Ithaca) Agr. Expt. Sta. Mem., 

 6:97^70, 1915- 



