DISEASES OF PLANTS. 357 



and the under<>round roots. The general effect of the .smut upon tlie 

 host is described, and data cited from which it is conchided that 

 the loss to the corn crop in the State amounts animally to about 2 per 

 cent. Numerous experiments are cited for the prevention of the dis- 

 ease, showing that it can not 1)0 controlled by seed treatment. The 

 corn smut seems to be more dependent upon its sporidia for its infection 

 than any other smut of cereals. Infection takes place rarely, if at all, 

 through the germinating seed, but is aerial and local. Winds serve as 

 the carrying agent for the sporidia of the plants and land can not be 

 selected that will be entirely free from smut. It is suggested that l)y 

 avoiding the use of manure, planting the crop where smutted crops have 

 not been grown the previous season, and careful cultivation would 

 reduce the amount of smut to a minimum. Mutilation of plants at 

 certain stages of their growth tends to largely increase the amount of 

 smut. This is particularly true in the case of topping. Some obser- 

 vations indicate that different varieties of corn vary in their suscepti- 

 bility to the disease, but this point must be confirmed by further ex- 

 perimental work. 



Grain smut of .sorgJium and hroorti c(yrn (pp. 335-346). — The grain 

 snmt of sorghum and broom corn {Clntract/amrghi-vulgariH) has been 

 investigated at considerable length b}^ the author. With broom corn 

 this smut trends to produce an inferior brush, and while ordinarily 

 fields do not have a very high percentage of smut, yet, on the whole, 

 it is considered the worst fungus enemy of this crop. On the sorghum 

 the smut tends to reduce the size and weight of the cane. Investiga- 

 tions showed that the smutted cane possessed a somewhat higher per- 

 centage of sugar, but the quantity of juice was reduced about in pro 

 portion to the reduction in the size and weight of the cane. The smut 

 seriously affects the production of seed and, on the whole, lessens the 

 yield of sorghum. It is recommended that sorghum and broom corn 

 seed should be soaked for 15 minutes in water heated to 135^ F. This 

 method seems to be the most satisfactory and, as but little seed is 

 required in planting these crops, the objection generally raised against 

 the hot- water treatment of oats can not be urged. 



Head smut of sorghum (pp. 346, 347). — This smut {C. reiliana) differs 

 from the common grain snnit of sorghum in converting the whole pan- 

 icle into a large irregular mass. It has been reported as occasioning 

 considerable damage in some localities, and in 1898 field experiments 

 were conducted with a view of infecting the Orange variety of sorghum 

 with this smut. Negative results were obtained in all the experiments, 

 and it is thought probable that the variety was, to some extent at least, 

 responsible for these results. 



Grain smut of Hungarian gixiss (pp. 347, 348). — The presence of 

 Ustilago crameri is noted in the spikes of cultivated millet. Generally 

 only the lower parts of the glumes are destroyed, the fungus showing 



