THE FUNGI WHICH CAUSE PLANT DISEASE 651 



infection. The ascigerous stage was said by Smith ^ to be a 

 Neocosmospora and the many wilts caused by Fusarium have by 

 various authors M'ho follow 

 Smith been reported as 

 Neocosmospora though 

 without real evidence that 

 they are such. See 

 page 205. 



Recent studies of Hig- 

 gins'*' and Butler^ ra- 

 dicate that the Fusarium 

 of the Neocosmospora is 

 a saprophyte and that the 

 Fusariums parasitic in the 

 wilt diseases are as yet 

 unknown in ascigerous 

 form. 



The Fusarium parasitic 



on cotton is believed to Fiq. 442.— F. vasinfectum, showing thromboBiB 



be identical with that on °^'''^- ^fter AtkinBon. 



okra but distinct biologically if not morphologically from that 



of watermelon. 



F. vasinfectum var. tracheiphila E. F. Sm.^' 



This form on cowpea, which appears to be morphologically 

 identical with F. vasinfectum is not capable of infecting cot- 

 ton. 



F. niveum E. F. Sm.*"*' '*^'''* is the cause of the watermelon 

 wilt. Morphologically it is like F. vasinfectum. 



A fungus regarded by Reed ^^' '*' as identical with this was also 

 described as causing wilt of ginseng. 



F. vasinfectum var. pisi v. Hall has been described as a variety 

 affecting the pea.'*** ^ 



F. udum Butler on pigeon pea in India is closely related to 

 this last fungus. 



F. aurantiacum (Lk.) Sacc. is recorded for cucurbs occurring 

 on stems, leaves and fruits. 

 ,.^ jirysporum Schl.^'- ^ 



Sporodochia conviex, subverrucose, rose, erumpent, confluent; 



