) DISEASES DUE TO FUNGI 63 
The former has been reported as a common cause of 
‘damping off”’ in many plants, and probably has been 
confused many times with various species of Phytophthora, 
from which genus it differs but slightly. Ward reported 
it as being very prevalent in the garden soils of Europe. 
Colletotrichum oligochetum is fully described under 
** Anthracnose of the Cucumber,” and is a common 
cause of “ damping off”? of cucumbers in this country. 
The methods of control recommended for “‘ damping 
off’ of tomato seedlings apply equally well to that of 
cucumber seedlings. 
FOOT ROT AND COLLAR ROT OF THE TOMATO 
These terms have been applied to diseases due to a 
number of different fungi, and in order to avoid 
confusion the name of the fungus concerned is here 
placed before the general term. ‘The most important of 
these diseases are Phytophthora foot rot, Botrytis foot 
rot, Macrosporium foot rot, and Verticilliwm collar rot. 
Typically these diseases appear about the soil level, and 
while the disease symptoms may vary the final result is 
the death of the plant. 
Phytophthora Foot Rot.—Two species of Phytophthora 
produce foot rot of the tomato, the most common 
being that described by Pethybridge and Lafferty (37) 
as Phytophthora cryptogea, which, as already stated, causes 
“damping off” of tomato seedlings. The symptoms 
of foot rot are identical with those of “‘ damping off,” 
except that older plants are concerned (Fig. 7), and 
there is a gradual transition from ‘“‘ damping off” to 
“foot rot” in accordance with the age of the plant at 
the time the disease appears. In some cases plants 
eighteen inches high have been known to be attacked. 
The disease is characterized by a dark brown or black 
discoloration of the outside tissues of the stem. At 
such parts the stem tissues shrink and collapse, causing 
