356 



DISEASES OF ECONOMIC PLANTS 



The smut closely resembles the stinking smut of wheat. 

 The affected ovaries or grains are transformed into stum 

 masses which remain within the glumes, and so resemble the 

 normal grains as to often be mistaken for them. The fungous 

 mycelium grows within the stem tissue of the diseased 

 plant, and, as is the case with wheat bunt, infection prob- 

 ably occurs in the seedling stage, and the fungus remains un- 



FiG. 153. — -Three rice spikelets : .4, normal ; fi, smutted ; 

 r, glumes partly torn away exposing the spore mass. 

 After Anderson. 



noticed until its presence is disclosed in the place of the 

 grain, as a black spore mass. 



The disease can be controlled, should it again appear, by 

 the methods which stamped it out in South Carolina ; that 

 is, by floating out and removing the light and smutted seeds 

 in cold water, then soaking the seed for twenty-four hours 

 in liver of sulphur, 11 pounds in 25 gallons of water, or by 

 employing a 2 per cent solution and soaking the seed only 

 two hours. 



Damping off. — Two forms of damping off of seedUngs 

 are known : — 



