FOOT-ROT DISEASES OF WHEAT IN AMERICA 17 
workers report that introduced or nonacclimated varieties are more 
susceptible to take-all than are local ones. It is also stated by others 
that early varieties and red wheats are more subject to take-all than 
are the late sorts and the light-colored varieties. _ 
Although the work being carried on by the United States Depart- 
ment of Agriculture and the cooperating State experiment stations 
has not progressed far enough to warrant the publication of definite 
control measures based entirely thereon, it seems evident that certain 
measures can be safely recommended. They are as follows: 
(1) If possible, avoid the use of seed from take-all infested fields. If abso- 
lutely necessary to use such seed, it should be cleaned very thoroughly and 
given a standard seed treatment. 
(2) Avoid the continuous cropping of take-all infested land with wheat, 
barley, rye, or any of the other grass crops which may be severely attacked 
by Ophiobolus graminis. 
(3) Use nitrogenous fertilizers with caution. 
(4) Rotate with oats, root crops, or other crops which are known to be 
immune from the attacks of the parasite. None of the maize or sorghum 
species or the legumes have yet been found to be attacked by Ophiobolus 
graminis. 
(5) In localities where summer fallowing is practiced, this method of con- 
trol may be advantageous. Fallowed land should be kept free from wild or 
weed grasses. When practicable, such fallowed land should be cropped at 
least one year with a nonsusceptible crop, such as oats, corn, the sorghums, 
or a legume, before wheat is again sown. 
THE FOOT-ROT CAUSED BY HELMINTHOSPORIUM SATIVUM 
COMMON NAMES 
Root-rot, America. Bolley (10). 
Foot-rot, America. Stevens (66). 
Helminthosporium blight, America. Weniger (74). 
Helminthosporium disease, America. McKinney (43). 
Because the parasite causing the Helminthosporium disease at- 
tacks all parts of the wheat plant, several names have been applied 
to describe the various symptoms produced. However, as this bul- 
letin deals primarily with the foot-rot phase, the other types of 
injury will be taken up only incidentally. 
GEOGRAPHIC DISTRIBUTION 
Mangin (57) in France, Palm (52) in Java, Pridham (45), 
Waterhouse (71), and Hamblin (26) in Australia, and Butler (12) 
in India have found species of Helminthosporium associated with 
diseased wheat, but in most cases the exact species involved are 
questionable or unknown. Butler (12) states that in India wheat is 
attacked by several species or forms of Helminthosporium. 
Drechsler (79) in his biblhographical treatment of the Helmintho- 
sporium diseases of certain grasses concludes on a basis of the litera- 
ture that Palm and Hamblin were working with Helminthosporiwm 
sativum. Christensen (73) states in this connection that he has seen 
Hamblin’s organism and that it is H. satévwm. Christensen says, 
further, that he also has obtained cultures of H. satiwwm from 
Canada, Mexico, and Argentina, and he concludes that the disease 
is prevalent in these countries. 
In this country severe Helminthosporium attacks on wheat were 
first reported by Beckwith (4) and Bolley (9, 70) in North Dakota. 
44918°-—25_3 
