TWO SCLEROTIUM DISEASES OF RICE 
By W. H. Tisdale 
Pathologist in Charge of Cereal Smut Investigations , Office of Cereal Investigations , 
Bureau of Plant Industry , United States Department of Agriculture 
SEEDLING-BLIGHT CAUSED BY SCLEROTIUM ROLFSII SACC. 
Iii the spring of 1919 the Office of Cereal Investigations undertook a 
study of the rice diseases of the United States with field headquarters 
for the work at the Rice Experiment Station, Crowley, La., conducted 
cooperatively with the Louisiana Agricultural Experiment Station. On 
June 12 of the same year Mr. J. Mitchell Jenkins, superintendent of 
the Rice Experiment Station, called the writer’s attention to a seedling- 
blight occurring in Honduras rice and resembling maggot injury. After 
close examination of diseased plants, no signs of the root maggot could 
be found, but the constant association of mycelial fibers and brown 
sclerotia with diseased parts was good evidence that the disease was of 
fungal origin. As the season advanced, the disease was found occurring 
to a greater or less extent in the various sowings on the Station farm. 
Varieties of both the long-grain and short-grain types of rice were affected. 
In the summer of 1920, the disease was equally as abundant on the experi¬ 
ment farm. It was found also on other farms near Crowley but was not 
so abundant. Later in the summer of 1920, while the author was at 
Gueydan, La., studying the “straighthead ” disease of rice, the farmers 
seemed to be more interested in a seedling-blight which had been causing 
considerable damage in that vicinity. According to their descriptions of 
the disease it was identical with the seedling-blight at Crowley, although 
it was too late to obtain specimens for identification. Reinking 1 reports 
the occurrence of a Sclerotium disease of rice in the Philippine Islands. 
He states that damage is caused in the seed bed and in rice near maturity, 
where the stems are attacked and sterile heads result. Reinking did not 
attempt to place the fungus specifically, but cultures of the Philippine 
form obtained from Mr. G. O. Ocfemia, a Philippine student in plant 
pathology at the University of Wisconsin, apparently are identical mor¬ 
phologically with the form in Louisiana. 
symptoms 
The appearance of small areas of blighted or dead seedlings is the first 
noticeable sign of the disease in the field. (PI. 122, A.) These areas 
tend to follow the drill rows, and a part or all of the seedlings may be 
1 Reinking, Otto A. Philippine economic-plant diseases. In Philippine Jour. Sci. Sect A, v. 13, 
no. 5, p. 228. 1918. 
Journal of Agricultural Research, 
Washington, D. C. 
yv 
(649) 
Vo!. XXI, No. 9 
Aug. 1, 1921 
Key No. G-243 
