Vol. LXXIII, No. 42G9. 
NEW YORK, AUGUST 22, 1914. 
WEEKLY $1.00 PER YEAR, 
ROOT DISEASES OR SOIL “SICKNESS” OF 
WHEAT. 
Low Yields Not Always Due to Poor Soil. 
UNGUS TROUBLES.—The wheat yield and the 
price of wheat in this country, at least in the 
corn belt, have been so low for many years that 
its production is conducted on a very narrow mar¬ 
gin of profit. In addition to this, the yield is so 
variable as to introduce much uncertainty into the 
crop, since an actual deficit often results in a poor 
year. Various attempts have been made to locate 
the trouble and devise remedies; but while some im¬ 
proved practices have given results that are really 
remarkable, it has not been possible up to the pres¬ 
ent time to put wheat growing in the corn belt in 
the clear money-making position which so important 
a crop should occupy. Recently, however, some 
studies have been made of crop-limiting factors as 
applied to wheat which give promise of enabling an 
increase in yield at a small expense to the farmer. 
These studies have to do with some inconspicuous 
blight diseases caused by a number of seed and soil- 
borne fungi. This discussion will be limited to a 
consideration of this phase of wheat production; 
not, however, with the idea of minimizing the im¬ 
portance of other and longer studied factors. 
INVESTIGATING THE FUNGI.—The work on 
these diseases has, directly or indirectly, been car¬ 
ried on in a large number of places. In this country 
the Ohio Experiment Station, the Bureau of Plant 
Industry of the U. S. Department of Agriculture, and 
the North Dakota Experiment Station have been 
most active in investigating them. The investiga¬ 
tions at the last named station have probably in¬ 
cluded more field observations and trials than any 
of the others. This work (reported in North Dakota 
Bulletin 107) coupled with laboratory work done 
there and at other places, has shown that at least 
six species of fungi aside from the well-known 
smuts and rusts operate to produce disease in wheat, 
or at least regularly accompany it. Most of these 
fungi are harder to fight than are the smut fungi, 
too, not only because they and their work are not 
so easily detected, but also because they are able 
to live, grow, and fruit on dead matter and can, 
therefore, maintain themselves for some line in the 
soil without their host plants. They occur and do 
damage throughout the range of wheat culture, but 
they are most abundant and their ravages are most 
severe where wheat is the main crop and is there¬ 
fore often raised year after year on the same soil, 
as in the Northwest and in Canada. 
SYMPTOMS.—The symptoms of attack by these 
fungi vary considerably, but are usually sufficiently 
definite to indicate the disease. Infected seedlings 
are usually stunted, the leaves may turn yellow or 
brown so that they are described as having “tip- 
burn.'’ “sunscald,” etc., and many of them may die. 
The root system is smaller than in normal plants 
and many of the roots are in various stages of de¬ 
struction by one or more of the fungi. Often they 
are so thoroughly destroyed as to give the impression 
that they have been eaten by insects. The infected 
roots may be black or pinkish. Normal roots vary 
from pure white to greenish. The stooling of such 
plants is seriously checked. Many times from one 
to a few stalks mark the limit of a plant in this 
matter. The straw is often soft and breaks over 
easily. It often has deformations at the joints which 
are usually taken for insect attacks. The heads do 
not till properly. In many cases only the lower half 
of the head is tilled, the upper half being empty or 
filled with shrivelled light grain. The quality of 
the grain itself is poor. Instead of being dark in 
color and hard and horny in texture it is light and 
soft—distinctly inferior in milling quality. Many 
grains are black at the stem end and others are 
pinkish all over. Many others are shrivelled or cur¬ 
iously puffed up or blistered and light in weight 
Such is a brief statement of the chief symptoms 
visible to the unaided eye. With laboratory facili¬ 
ties it is possible wtliout much difficulty to examine 
the spores which occur on the outside of the grains 
and from the kind and relative numbers present 
come to some conclusion as to disease conditions. 
SOURCES OF INFECTION.—The chief sources 
T1IE FIRST LESSON IN MILKING. Fig. 437. 
