VEE 
under similar conditions. Accordingly, the young parasite is pres- 
ent to invade the susceptible seedling stage of the host. 
In certain localities, however, the epidemics of smut are due to 
the presence of spores in the soil. This is particularly the case in 
eastern Washington and Oregon and also in Idaho. In threshing, 
the smut spores from an infected crop are blown out from the 
machines in enormous quantities and scattered long distances. In 
severely infected crops these are spoken of as smut showers. 
These spores land on the soil, especially in the fallow fields which 
are ready for the fall seeding. As soon as the autumn rains come 
the spores germinate and form a more or less saprophytic growth 
in the soil. When the seed is sown in such soil the young seed- 
lings are likely to become attacked. 
The Loose Smut of Wheat.—The loose smut of wheat also is 
coextensive with the cultivation of wheat. Ordinarily it is not a 
particularly severe disease. In some sections of Ohio, Indiana, 
Illinois, Missouri, and Virginia, however, one frequently finds 5 
to 10 per cent. of the wheat destroyed, and in occasional fields as 
much as 20 per cent. This disease is recognized by the so-called 
“black heads” which are conspicuous soon after the wheat heads 
out. The black color of the head is due largely to the spores of 
the fungus which have been formed at the expense of the develop- 
ing wheat tissues. These spores are readily disseminated by the 
wind, and soon nothing but the naked axis of the inflorescence is 
left (Fig. 2). 
There is a very important difference in the life history of the 
loose smut of wheat as compared with bunt. The diseased plants 
shed the spores at about the time the normal, healthy plants have 
come into bloom. The spores are scattered by air currents and 
distributed upon the flowers of the healthy plants. Some of them 
reach the stigma of the flower and there germinate. The young 
mycelium grows down into the tissues of the ovary. As the kernel 
matures there is a slight growth of the fungous mycelium, but 
externally there is no evidence that the tissues of the kernel are 
really invaded by a parasite. The kernel apparently develops in a 
normal manner and appears entirely healthy. As a matter of fact, 
however, in these ripe kernels one may find a small amount of 
