2 BULLETIN" 1116, V. S. DEPARTMENT OF AGRICL^LTURE. 



means of prevention extremely desirable. Some work was started 

 by the Office of Cereal Investigations in the spring of 1919 at Crowley, 

 La., in cooperation with the Louisiana Agricultural Experiment 

 Station. These investigations were continued for two years, but 

 were given only minor attention because a number of other diseases 

 were considered more important at the time. However, some results 

 were obtained which are thought to be of value, especially to those 

 who may undertake further investigation of these problems. 



The investigations reported herein were undertaken with the hope 

 of clearing up the cause of the leaf-spot and seedling blight and, if 

 possible, to find some means of prevention. During the short period 

 of these studies the writer's attention was drawn to what appears to 

 be the more important phase of this problem, namely, the staining 

 and decay of rice in shock and storage. The nature of the market- 

 able product is such that a very small percentage of stain or decay is 

 reflected very decidedly in the grade. As previously mentioned. Van 

 der Wolk states that 0.3 per cent is sufficient to cause rejection in the 

 European markets. 



FACTORS FAVORING THE DEVELOPMENT OF THIS DISEASE. 



If the harvest season is wet and the rice remains in the fields, espe- 

 cially in shock where it does not dry out, stack-bm-n is likely to develop. 

 Such rice generally is found of poor quality when milled. This stain- 

 ing of the grain is masked to a certain extent by polishing, but this 

 is only temporary, as the pohsh gradually disappears and the decay 

 continues to develop. If the rice is stored in a damp place after mill- 

 ing or if not thoroughly dry before storing, it is subject to this type 

 of injury. Repolishing is resorted to at times by millers to mask the 

 discolorations in the rice. This would be more effective if the stains 

 were superficial and were not subject to further development. Rice 

 with slight infections of this type when shipped in damp, warm cars 

 or bottoms for considerable distances, or when allowed to stand for 

 many days under such conditions, may reach its destination with 

 sufficient injury to cause it to be rejected. If not rejected, it would 

 be given an inferior grade on the market. Small flecks, which might 

 escape the observation of the most critical observer, are capable of 

 spreading and destroying the entire kernel when the grain is placed 

 in a warm, damp place. The exact degree of moisture required to 

 cause these stains to develop is not known, but the humid atmosphere 

 of the southern rice sections is kno\STi to favor tliis trouble. High 

 temperatures, which are also common in the South, favor the develop- 

 ment of these stains. If the rice is stacked damp or is allowed to 

 go through a sweat after stacking it is likely to become stained if 

 the temperatures remain sufficiently high for a few days. 



