4 BULLETIN 70. 
more or less influence on the death of the plants. The 
stems which had been dead for sometime were so complete¬ 
ly overrun by other fungi that it was often difficult to 
identify the Rhizoctonia hyphae. 
This Department has received many inquiries from po¬ 
tato growers in various sections of this State in regard to 
failures of the potato crop. Many of these inquiries gave a 
description of a diseased condition which is strikingly simi¬ 
lar to the one that was so common on Long Island in 1900. 
After examining the tubers and stems from various parts of 
the state, it is quite evident that the fungus is common to 
nearly every section of this state, and especially abundant 
in many parts where failures occur. This information and 
the previous observations led us to believe that it is a para¬ 
site on the potato plant and that it probably had some in¬ 
fluence on the failures recorded in these various sections. 
Accordingly the writer was detailed to take up this work 
and the results of the investigations and experiments are 
given in the following pages. 
Our experiments prove that Rhizoctonia is an active 
parasite on the potato plant. Species of this fungus or pos¬ 
sibly the same species occur on a great variety of plants 
among which may be mentioned the following: Beets, car¬ 
rots, alfalfa, red clover, onions, turnips, peas, celery, lettuce, 
beans, cabbage, blackberries and raspberries. Usually it is 
a parasite but it is capable also of existing on dead 
organic matter in the soil and when favorable opportuni¬ 
ties occur it invade^ and destroys the living tissues of 
plants. 
The annual loss to the State from this disease is con¬ 
siderable. In many localities where potato growing was 
once a paying industry the soil has become so infected with 
the fungus that the crop is no longer profitable. Although 
it is more or less common to many fields, it apparently de¬ 
velops most rapidly in heavy soils which are poorly drained. 
The disease remains in the soil and grows worse with each 
succeeding crop, consequently failures are most apt to oc¬ 
cur where a systematic rotation of crops is not followed. 
Probably every state in the Union suffers more or less 
injury to its potato crop from this disease. It is known to 
be common to the fields of New York, Ohio, Iowa, Minne¬ 
sota, Wisconsin, Florida, Oklahoma, Texas, Colorado, Cali¬ 
fornia and Washington. 
EFFECTS OF THE DISEASE ON POTATO PLANTS. 
In many sections of the State where potatoes,, are not 
successfully grown it is reported that large vines are pro- 
