* Large Potato Vines and No Potatoes 
By Wendell Paddock. 
This bulletin contains a condensed account of our work with 
potato diseases, the most of which has appeared in Bulletins 70 and 
91 of this station, and its purpose is to supply information to the 
increasing number of correspondents who are becoming interested 
in potato growing. It is addressed primarily to those farmers who 
live outside of the successful potato-growing sections, but the best 
potato soils are by no means free from the troubles that are de¬ 
scribed below. By having a correct understanding of certain pe¬ 
culiar conditions of the potato plant, which have been ascribed to 
various causes, such as water, alkali, altitude, etc., it is possible that 
the most successful grower can modify his system of culture to 
advantage. 
Most farmers who have tried to grow potatoes in this state and 
failed, or who^ have been only partially successful, will be familiar 
with the following conditions: 
Good vines with no tubers or a cluster of small, worthless tu¬ 
bers ; in many instances, even in the best potato soil, the plants fail 
to come up, or weak plants are produced, which die before the pota¬ 
toes are mature, thus resulting in a poor stand; potato blight, or 
the dying of a portion or all of the vines; russeted and scabby pota¬ 
toes ; blight and scab also seen in the best potato districts; and finally, 
collar rot or black ring of the vine, at the surface of the ground. 
Experiments have proven that any and all of these conditions 
can be produced by the action of a certain plant disease, and obser¬ 
vations in many parts of the state show that this fungus is abundant, 
and is undoubtedly responsible for most of the lack of success in 
potato growing. 
Nature of the Disease. This fungus (Corticium vagum B. & C. 
var. Solani, Burt.) appears to grow naturally in this state, as it is 
found in the remote and newer parts, and it also attacks a number of 
plants other than the potato, both cultivated and wild. After the 
soil has become infected the fungus persists for a long time.- 
If the fungus is not already present, the soil will soon become 
infected after potatoes have been grown. This is true for the rea- 
*Bulletins 70 and 91, by F. M. Rolfs, being technical in character, have 
not been sent to the general mailing list.. Copies will, however, be sent on 
request. 
