Cereals 



301 



partially fill. The dead portion of the plant may bleach or 

 darken according to environment, resulting in varied char- 

 acters in later stages of the disease. In 70 per cent of 

 the cases examined by Metcalf the lowest 

 joint of the rachis was affected, and in 

 consequence the heads broke off at this 

 point. This gives rise to the common 

 name "rotten-neck," but since the char- 

 acter is not universal, the name is not an 

 appropriate one. 



The chief damage results from the failure 

 of the grain to fill on the diseased stalks. 

 An early attack may render a crop entirely 

 worthless. Plants attacked later, yield 

 some grains which are of poor, light qual- 

 ity, easily broken or blown away, and con- 

 sequently largely lost in threshing and 

 milling. The variation in size of the grain 

 also largely depreciates the quality. Many 

 of the heads, especially the heavier ones, 

 fall off, and some fields show at least 

 one-third of the crop thus left upon the 

 ground. 



The Rice Committee of the Agricultural 

 Society in South Carolina, March, 1904, 

 estimated the loss, up to that time, to be 

 very nearly $1,000,000. Depreciation in 

 land values, necessitating abandonment of 

 land, is a significant item of charge against 

 this disease. 



The chief hope lies in the use of resistant 

 varieties. Withholding nitrogenous ferti- 

 lizers and removal of infective trash by 

 burning are good sanitary measures. 



Green-smut (Usfilaginoidea virens (Cke.) Tak.). — This 

 grain disease, though partaking of the appearance of a true 

 smut, is in reality more closely related to the ergot of rye. 



Fig. 158. — Rice 



blast. After 

 Fulton. 



