FOOT-ROT DISEASES OF WHEAT IN AMERICA 29 
this disease. During the preheading and later stages of develop- 
ment the diseased plants usually show various degrees of root and 
culm rotting. Upon endeavoring to pull diseased plants from the 
soil they often break away from the crown or the roots, and the 
bases of the culms and the roots show a brown to black coloration 
resembling a charred condition produced by fire. A mycelial plate 
somewhat similar to that produced by Ophiobolus graminis has 
been found associated with this disease rather frequently, but in 
many cases this plate tends to be brown rather than black in color, 
and it seems to be somewhat less extensive on the plant than is the 
case with the plate produced by O. graminis. Another difference 
which seems apparent between take-all and this foot-rot is that the 
basal discoloration and rotting seem to extend farther up the stems 
of plants affected by the foot-rot in question. This foot-rot seems 
to cause a collapsing of the cells at the base of the culm. These 
tissues contract (Pl. V, C), become brittle, and the stems break over, 
causing general lodging of the affected plants in infested areas. 
This condition has been recorded by Delacroix (17), and the writer 
has also noted it in connection with take-all, in which case it seems 
to be exceptional rather than typical. The writer has never noted 
this condition associated with the Helminthosporium foot-rot. 
In general, the brown coloration associated with this foot-rot tends 
more toward black; it seems to be more diffused and to penetrate the 
tissues at the base of the culm more completely than the browning 
caused by Helminthosporium sativum. Brown-colored elliptical 
lesions with light-colored centers are frequently found on the dis- 
eased plants, but these lesions are larger than those produced by H. 
sativum, and upon plating such lesions H. safiévwm never has been 
obtained. However, a uniform type of sterile fungus has been ob- 
tained very regularly by Hurley Fellows, who is associated with the 
writer in these studies. 
CAUSE OF THE DISEASE 
The cause of this foot-rot has not been determined. It has been 
suggested that frost and general winter injury are the prime causes, 
but the evidence in hand indicates that these factors may act only as 
contributing factors rather than as direct causes of the disease. Sev- 
eral fungi have been found associated with the trouble, but their 
exact relation to the disease is not known. In 1919 a small number 
of mature perithecia of Leptosphaeria herpotrichoides De Not. were 
found ** on diseased wheat plants collected by the writer near Spo- 
kane, Wash. In 1921 he (47) found Wojnowicia graminis (Mc- 
Alp.) Sace. and D. Sacc. (Pl. VI, A and #) associated with the dis- 
ease as it occurs near La Grande, Oreg. This organism has been 
found in that region each year since the first observation was made. 
In 1923 H. Fellows found this organism associated with diseased 
plants near Spokane, Wash. Several sterile fungi have been isolated 
from the tissues of diseased plants, but there seem to be two prevail- 
ing forms in the Spokane and La Grande districts, one of which pre- 
dominates and resembles the mycelial growth of W. graminis, the 
* former resembling that of L. herpotrichoides. 
% This fungus was identified by Mrs, Edith Seymour Jones and the writer, 
