SORGHUM BLIGHT. 535 



and carried out successful experiments in infection of healthy 

 Sorghum. 



Diseased iields should have the Sorghum stubble burnt out, 

 and other crops cultivated on them for several years. 



Bacterial Disease of Maize.^ 



From dark slimy spots on young maize-plants which had died 

 from some unknown disease, Burrill isolated JBaeilhis secales. 

 Pure cultures were obtained and minutely described, but no 

 record is given of its use in infection-experiments. 



Red-coloration of Wheat. 



This is a phenomenon not uncommon on wheat-gram, where 

 it may be epidemic. Prillieux^ ascribes it to a Micrococcus 

 which he found associated with it.; as, however, neither pure 

 cultures were made nor any experiments in infection carried 

 out, the cause of the disease is still doubtful. Examination of 

 diseased grain showed that the starch-grains and even cell-walls 

 had been dissolved. 



Mosaic Disease of Tobacco. 



This disease of the tobacco is well known in the Nether- 

 lands. It makes its appearance as a mosaic-like pattern on 

 the leaf, due to isolated spots becoming light-green, then dying. 

 Mayer ^ ascribes the disease to the iniiuence of bacteria, although 

 infection-experiments have hitherto failed ; other observations 

 on the disease do not confirm this conclusion. 



Potato-Rot.* 



Kuhn described a dry-rot or tuber-rot of the potato which 

 had been known since 1830. The disease appears generally 

 after harvest and lasts till spring. The tubers shrivel up and 

 become very brittle. 



^Burrill, Agric. Exper. Station, Univ. of Illinois, 1889. 



^AnnaUs d. sci. natur., Ser. VI., 8, 1878, p. 248. 



3"Ueber die Mosaik-krankheit des Tabaks," Versuchs-siation, Vol. 32, 1886. 



•^ Kiihn, Die Krankheiten d. Kiilturgewcichse, 1858. 



The text-books of Frank aud Sorauer. 



Beinke and Berthold, Die Zersetzunrj d. Kartoffel durch Pihe, 1879. 



Kramer, Oeslerreich. landwirth. Centralhlatt, 1891. 



