SEEDLING BLIGHT AND STACK-BURN OF RICE. 3 
CAUSES OF INJURY. 
The seed-injury phase and symptoms of the trouble were touched 
upon previously by Godfrey,? who reported the occurrence of a leaf- 
spot on rice in Louisiana in 1916. He said the disease looked very 
much like the black rust of cereals. Again in 1920, after the writer’s 
investigations were begun, Godfrey* reported the occurrence of a 
—__ seedling disease of rice and 
states that the cause was 
found by Dr. H. B. Hum- 
phrey to be due to an or- 
| ganism belonging to the 
Mycelia sterilia group of 
fungi. The fungus was 
characterized by very small 
black sclerotia and a white 
sterile mycelium. He fur- 
ther states that the fungus 
closely resembles the Sclero- 
tium found associated with 
the leaf disease reported in 
1916. Godfrey found the 
| fungusconstantlyassociated 
with rice seed grown in 
Louisiana, particularly the 
Blue Rose and Honduras 
| varieties. California seed, 
however, was found to be 
free from the fungus. 
The cause of these troubles 
was found to be much more 
complicated than the notes 
| by Godfrey would seem to 
indicate. Van der Wolk 
_| found the fungus Protoascus 
=| colorans to beresponsible for 
Fic. 1.—Black leaf-spot ofrice caused by the sclerotial fungus id yellow orains.”’ - The col- 
a which produces seed injury and seedling blight. or appeared after the rice 
had been in heapsforconsiderablelengthsof time. Thewriterfound the 
small sclerotial fungus of the Mycelia sterilia group mentioned by God- 
| frey* to be constantly associated with the leaf-spot (Fig. 1) mentioned by 


2 Godfrey, G. H. Preliminary notes on heretofore unreported leaf disease of rice. _(Abstract.) In 
Phytopathology, v. 6, no. 1, p. 97. 1916. 
3 Godirey, G. H. A seed-borne Sclerotium and its relation to a rice-seedling disease. In Phytopath- 
ology, v. 10, no. 6, p. 342-343. 1920. 
4 Wolk, P.C.vander. Op. cit. 
