
WASHINGTON, D. C. PROFESSIONAL PAPER November 13, 1922 
SEEDLING BLIGHT AND STACK-BURN OF RICE AND 
THE HOT-WATER SEED TREATMENT. 
By W. H. Tispate, Pathologist in Charge of Smut Investigations, Office of Cereal Inves- 
tigations, Bureau of Plant Industry. 
CONTENTS. 
Page. Page 
OPES ENE 2 or a a fi} Causes Of Injury -=.=.2. 52 32.2)4-.2s52255 eee 3 
Factors favoring the development of this dis- peed treatment. 5.2.22: .222 so sat eee ee 6 
PASC So 2 a ee Sa oA Ei eS VEAECOUCTISIONS: 2) 202 - cose aos 2 ee ee 10 
INTRODUCTION. 
The rice crop of the southern part of the United States suffers 
heavy annual losses due to the staining and decay of the grain in the 
shock and in storage, both before and after milling, and to poor 
germination of the seed when sown. The former is much more 
important than the latter. Occasionally fields have to be reseeded, 
_and others have poor stands. The milled product, on the other hand, 
is considered of inferior quality if only a low percentage of the grain 
is flecked or decayed. Van der Wolk,! in discussing the trouble 
known to the European rice trade as “yellow grains,” says that it 
is “‘one of the most fearful calamities in the trade rice of some coun- 
tries.” “Yellow grains”’ is similar to the stains which develop in our 
southern rice. It is caused by a different fungus, which accounts 
for the difference in color. The disease appears in our American 
rices as flecks or totally decayed grains which are yellowish brown to 
dark brown in color. The term “stack-burn”’ often is applied to this 
form of injury by rice growers and millers. “Stain” and “ flecking” 
are other terms used. 
The decay of rice seed in the soil and the staining and decay of the 
commercial product make investigations for determining causes and 

1 Wolk, P.C. van der. Protoascus colorans, a new genus and a new species of the Protoascinex group, 
the source of ‘yellow grains” in rice. In Mycol. Centralbl., v. 3, no. 4, p. 153-157, l col. pl. 1913. 
3866°—22—Bull. 1116 
