Fungous Diseases oe Coeorado Crop Plants 
9 
account of Rhizoctonia in Colorado. In 1904 (Rolfs, F. M., “Po¬ 
tato Failures,” Bull. 91, Colo. Exp. vSta., 1904) Rolfs published 
further notes on Rhizoctonia, in which he .gives additional informa¬ 
tion relative to the life history of the fungus, its injuries, spread, 
and remedial measures. 
The first mention of potato blight (Fusarium) is found in a 
press bulletin by Paddock in 1906 (Paddock, W., “Potato Prob¬ 
lems,” Press Bulletin No. 26, 1906). Within the last few years, 
and particularly during 19 ii and 1912, Fusariiim has seriously crip¬ 
pled the potato industry in many parts of the state. It is doubtful, 
however, if the organism, Fusarium oxysporum, is responsible for 
all the potato troubles in districts suffering. 
Other potato diseases such as early blight, internal brown spot, 
and potato scab have not developed in severity as have Fusarium 
and Rhizoctonia. Both of the latter diseases have made remark¬ 
ably rapid progress in the state. This is largely due to the general 
practice of growing potatoes continuously year after year on the 
sam.e soil. Colorado potato' failures, although lamentable, have been 
a blessing in disguise. They have brought forcibly to our attention 
the necessity of a proper system of crop rotation and the more gen¬ 
eral adoption of diversified farming. Crop rotation is a highly re¬ 
liable practice in the control of a great majority of diseases of field 
and garden crops. 
It is well that we keep on the watch for the first appearance of 
fungous diseases in the state. In many instances, the immediate 
suppression of a disease that has just been introduced may mean 
the saving o4 thousands of dollars to an entire community. Fun¬ 
gous diseases fluctuate in prevalence from year to year, largely de¬ 
pending upon climatic and weather conditions. If a disease is very 
bad one year, the chances are that there will be an abundance of 
infection material near at hand the following season. However, it 
sometimes happens that a serious outbreak is followed by a year of 
comparative freedom from disease. On the other hand, a serious 
outbreak may follow a year during which little disease was present. 
The Department of Botany of the Experiment Station will be 
ready at all times to identify promptly plant diseases that are sent in, 
and suggest remedies. 
DISCUSSION OF CHIEF FUNGOUS DISEASES 
ALFALFA. 
Bacterial Blight. —Diseased plants are stunted and lighter 
green in color than normal. Stems chiefly infected. Infected por¬ 
tions at first are water-soaked in appearance, and olive green in 
I 
