1 8 ' Research Bulletin No. g 



of thorough study by Appel and his coworkers (2, 4). Eventually 

 the plants infected with F. trichothecioides showed much severer 

 symptoms than those inoculated with F. oxysporum (fig. 6). Eight 

 plants died in the former sets, and 3 in the latter. Plants infected 

 with F. trichothecioides showed such severe and rapid burning and 



Fig. 4. — Leaf roll and rosette of field plant of the Pearl Variety; 

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



August 19 1 2, 



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 

 to which the inoculum had been applied, even in the leaf, where the 

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

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



