Family Solanaceae 327 



entire fields but is generally confined to individual 

 hills irregularly scattered in a field. In distribution, 

 VertidUium wilt has been found only in the more 

 northern States. 



Symptoms. The disease as described by Orton' is 

 characterized by a sudden wilting of the foliage (fig. 

 62 i) and the premature dying of the hill. In split- 

 ting ppen a diseased stem, the browning of the vessels 

 will be well marked. This will extend to the tips of 

 the stems and into the leaf petioles, a symptom which 

 distinguishes it from Fusarium wilt, since in the latter 

 the browning of the vessels does not extend into the 

 tips of the stalks. Moreover, in Verticillium wilt 

 there is a production of conidia on the stalks long 

 before they are entirely dead. In Fusaritim wilt, 

 the conidia appear only after the stem has been killed 

 for some time. 



Control. Since the disease is carried internally in 

 the seed tubers, control methods are the same as for 

 Fusarium wilt. 



Fusarium Wilt 



Caused by Fusarium oxysporum (Sch.) Sm. and Sw. 



Fusarium wilt is a disease which thrives best in 

 warm cHmates. In California, Arizona, Ohio, Mis- 

 souri, and Nebraska the trouble is most prevalent. 

 New England and New York are relatively free from 

 Fusarium wilt. There, however, the Verticillium 



' Orton, W. A., U. S. Dept. of Agr. Bui. 64 : 16-18, 1914. 



