426 
Journal of Agricultural Research 
Vol. XXVII, No. i 
DISTRIBUTION AND ECONOMIC IMPORTANCE 
To date (1923) flag smut of wheat has been reported as occurring in 
the United States, Australia, Japan, China, India, South Africa, Italy, 
and Spain. In the United States it has been found in Monroe, St. Clair, 
Madison, Jersey, Macoupin, Greene, Scott, Hancock, and Logan Coun¬ 
ties in Illinois; in St. Louis, St. Charles, Warren, Platte, and Buchanan 
Counties in Missouri; and in Atchison, Leavenworth, Wyandotte, and 
Miami Counties in Kansas. Field surveys to determine the distribution 
of flag smut have been made by the State of Illinois and the United 
States Department of Agriculture each summer for the period from 1919 
to 1923. The survey data for each year show that flag smut was found 
more widely distributed than in the previous year. This increase in the 
infested area may be due partly to the natural spread of the disease, 
and partly to the fact that larger areas were surveyed each year, or to 
either cause alone. From the earlier data it appeared that the disease 
was spreading rapidly, but evidence from the 1922 and 1923 surveys 
indicates that it probably has been present for two to several years even 
in areas reported for the first time to be infested. 
During the five years that flag smut has been known to occur in the 
United States the annual loss due to this disease in the surveyed areas 
probably has been less than 2 per cent. In parts of some fields, however, 
50 per cent of all plants within a given area have been infected. The low 
average percentage may be due partly to climatic conditions and partly 
to the fact that most of the time the infested areas have been under 
State quarantine regulations with regard to disinfection of all grain and 
threshing machines, the movement of straw, and the sowing of varieties 
which were found to be fairly resistant to flag smut. 
In the literature from Australia, where flag smut was noted first in 
1868 (9), losses of from 10 to 50 per cent of the wheat crop, due to this 
disease, commonly have been reported. However, according to informa¬ 
tion given by R. J. Noble, of Sydney, Australia, the average annual loss 
due to flag smut alone is about 3 per cent. In some years it is consider¬ 
ably higher, while in others it is practically negligible. Although flag 
smut has been distributed widely in the eastern wheat-growing area of 
Australia, it was not known to occur in Western Australia. However, 
W. M. Carne, who is engaged in plant research in Western Australia, in 
a letter to Dr. R. J. Haskell, stated that flag smut was recorded as oc¬ 
curring for the first time in that State in October, 1922, but on one farm 
only. 
Butler (2, p. 171-173, fig . 36) states that flag smut is confined to the 
Punjab in India, and that “it has not been reported as causing much 
damage” in that country. 
Hori (5) states that flag smut has been known in Japan since 1895 and 
that within an area of one-fourth acre, in the Province of Kai, in 1898, 
100 per cent of the plants were destroyed before flowering time. It has 
been reported by Hori (4 ) 4 from Gumma and Yamanshi prefectures, and 
from Higo Province by Yoshino (17 ). 4 Flag smut of wheat is not known 
to occur in Formosa and Korea. Hori ( 6 ) 4 further states that this smut 
is not so well known to the farmers as the other grain smuts, though 
infrequently it causes considerable damage. 
4 Japanese original translated by Dr. T. Tanaka, formerly botanical assistant and translator. Office of 
Crop Physiology and Breeding Investigations, Bureau of Plant Industry, U. S. Department of Agriculture. 
