Fiisar'ium hi Tuber Rot and IJUt of Potato 
19 
the whole plant took place, the fungus girdled the whole stem, 
while plants that were not girdled lived on, even though one side 
was entirely destroyed. There was little lateral and subsequent 
vertical spreading of the fungus from one vascular strand to the 
other. These experiments were repeated with 25 other plants and 
in most cases the same symptoms were observed. These symptoms 
have been repeatedly observed in the dry land areas of Xebraska, 
^ B 
Fig. 5. — Rosette produced in laboratory with Fiisarium oxysponau . and 
control plant: A. control. Early Ohio variety: B. rosetted plant. 10 days 
after inoculation. Early Ohio variety. 
but have always been looked upon as cases of "sun scald." and 
in previous experiments with wilting due to F. tricJiothecioidcs such 
cases were ignored. 
Plants grown in soil infected with F . oxysponim and F. triclio- 
thecioides showed severe lesions of roots and stolons. Examination 
of roots afifected with either organism showed that the cortical 
regions are first and most severely attacked, not only intercellu- 
larly. but also intracellularly, the cells being packed full with hyphae. 
In most cases the cortex could be sloughed off with exceeding ease. 
From the cortex the organisms invaded the stelar regions, where 
