igo6.] How Cereals are Infected with " Smut." 669 



Smut is a very destructive fungus which in the case of culti- 

 vated cereals shows itself under the form of a black powdery- 

 mass in the ear. The grain is completely 



How Cereals are destroyed, its place being occupied by the 

 Infected with . J ■ -/ s * ( . 



« Smut." fungus. Brefeld, a German mycologist, 



who has contributed so much to our 

 knowledge respecting the fungi popularly known as "smuts" 

 (JJstilago) and "bunts" (Tilletia), announced that infection 

 could only be effected during the youngest seedling stage of 

 the plant, such infection resulting from the presence of smut 

 spores in the soil, or was more frequently due to spores adhering 

 to the grain being sown along with it. The only known excep- 

 tion to this rule was maize, where infection was admitted to be 

 possible at any point of the full-grown plant where young tissue 

 was present. 



This statement was generally accepted, and all remedial 

 measures for the prevention of " smut " were based upon it. 



It is true that from time to time various observers have stated 

 that inoculation could be effected by dusting " smut " spores on 

 the flowers of oats or barley. Such announcements, perhaps, 

 did not receive the attention they deserved, but were promptly 

 dismissed with a reference to Brefeld. The very fact of 

 Brefeld's acknowledged authority thus for a time stifled further 

 progress. 



Quite recently, however, a series of experiments conducted 

 with great care by Hecke, a German botanist, has definitely 

 proved that the disease can be established by infecting the 

 young ear with " smut " spores. 



Ears of barley when in flower were moistened with water con- 

 taining " smut " spores in suspension, and at a later stage of 

 growth the mycelium was found to have penetrated into the 

 embryo or young grain. 



It follows that in future two distinct modes of infection have 

 to be taken into consideration in dealing with "smut" disease 

 in cereals: (1) Infection of the seedling by "smut" spores 

 present in the soil. This method of infection is combated suc- 

 cessfully by the well-known method of treating the " seed " with 

 formalin or other fungicide just before sowing. (2) Infection 

 by " smut " spores carried by wind alighting on the ear of corn 



