18 



Research Bulletin No. <> 



subject of thorough study by Appel and his coworkers i 2, 4|. Even- 

 tualh the plants infected with F. triehothecioides showed much se- 

 verer symptoms than those inoculated with F. oxysporum (tig. 6). 

 Eight plants died in the former sets, and 3 in the latter. I 'hints in- 

 fected with F. triehothecioides showed such severe and rapid burning 



I ig *.— Leaf roll and rosette of field plant of the Pearl variety; August 

 1912, at the U. S. Substation at Mitchell, Neb. 



and drying up of leaves that the typical wilting phenomena were 

 scarcely realized. The vascular bundles were blackened and the 

 blackening extended even into the petiole and the leaf veins. This 

 rapid killing was at first strictly localized on that side of the plant 

 t<> which the inoculum had been applied, even in the leaf, where the 

 leaflets on one side of the midrib would he affected, and those on 

 the other side not. Eventually in those cases in which killing of 



