296 



Diseases of Economic Plants 



The formalin treatment, 1 pint to 40 gallons, is applicable 

 to both of these smuts. 



MILO. See p. 307. 



OAT 



Loose-smut ^-^' ^^^"^"^^ {Ustilago avenos. (Pers.) Jens.). — 



Under the name "smut," "blackheads," etc., this disease is 



known wherever oats are 

 grown. Grain and more 

 or less of the chaff are 

 replaced by a powdery, 

 black mass, which shat- 

 ters out as it ripens, leav- 

 ing later only the naked 

 branches of the panicle. 

 Usually all the spike- 

 lets of a head and all 

 the heads of the affected 

 plant are smutted. 

 There is considerable dif- 

 ference in the resistance 

 offered by different va- 

 rieties, but in view of the 

 perfect protection af- 

 forded by proper treat- 

 ment this is of little 

 significance. 



The damage caused by 

 smut is commonly under- 

 rated. In 1884 Arthur 

 in New York by actual 

 count found the oat 

 smut to constitute from 

 8.5 to 10 per cent of the 

 Fig. 156. -Loose smut on oats. After ordinary crop. By ac- 

 Jackson. tual count of nearly 



