19 



plant through the seed — i. e. penetrating the very 

 young seedHng. I have this past season repeated the 

 experiment in the field — in ever\' case succeeding in 

 getting an abundaat crop of the smut. 



I have also to record for the first time the experi- 

 mental infection of the broomcorn plant with Ustilago 

 sorghi. The experiment was carried on in the field. 

 Clean seed was obtained and with this a quantity of 

 smut spores of Ustilago sorghi from common saccha- 

 rine sorghum was mixed. The majority of the stalks 

 in the row — hundreds in number — bore smutted heads 

 showing the efficiency of the seed infection. In the 

 same plot tests were made with hot water as a lungi- 

 cide for the grain sorghum smut (Ustilago sorghi). 

 The seed known to have adhering smut grains was 

 treated in the same manner as is usual for oats and 

 wheat to prevent Ustilago avenae and Tilletia tritici. 

 That is, the seed was immersed for fifteen minutes in 

 water heated to 133 degrees F. The following table 

 shows the result : 



Sorghum, seed not treated ; Number of stalks 205, 

 per cent, smutted 19,02. 



Sorghum, seed treated with hot water; Number of 

 stalks 179; per cent, smutted 1.12. 



Broomcorn, seed not treated; Number of stalks 

 310; percent, smutted 59.03. 



Broomcorn, seed treated with hot water ; Number 

 of stalks 293 ; per cent, smutted 3.10. 



Although this treatment did not wholly eradicate 

 the smut, it is evident that in a practical sense it would 

 be considered an efficient fungicide. As a matter of 

 fact, an enormous amount of smut was used to infect 

 the seed artificially before applying the hot water, and 

 the smut wafted by breezes in the laboratory where the 

 work was carried on would satisfactorily account for 

 subsequent infection and the consequent small amount 

 of smut in plants grown from the treated seed. 



