Cereals 319 



injury to the quality of the grain and diminution in quan- 

 tity. 



Selby has shown that seedHngs in the field are often killed 

 by this disease, which is carried over in the seed. In this 

 way as high as 5.9 per cent of death in seedlings has been 

 caused. 



It has recently been shown that the fungus that causes 

 wheat scab grows also on corn causing root-rot, and winters 



b a 



Fig. 167. — Wheat kernels: a, normal; b, shrunken and killed by 

 scab. After Manns. 



on corn refuse. Wheat planted in fields that bore infected 

 corn becomes badly diseased. One corrective practice, there- 

 fore, is to avoid sowing wheat on land so infested. 



Minor diseases 



Black-chaff ^^^' ^"'^ (Pseudomonas translucens) . — As the 

 wheat approaches maturity, black, sunken stripes appear 

 lengthwise of the chaff. The rachis and leaves are also at- 

 tacked. In severe cases the grain is shriveled. The disease 

 was found in 15 states west of Indiana in 1917. Thorough 

 screening and disinfection of seed by copper sulfate is ad- 

 vised. Leptosphaeria leaf-blight ^^^ (Leptosphceria tritici 

 (Gar.) Pass.). — The lower leaves are killed early in the 

 season. Large loss is not usual. The Glume-blotch ^''^ 



