SORGUUM BLIGHT. 535 



and carried out successful experiments in infection of healthy 

 Sorrjlium. 



Diseased tields should liave the SvrgJium stuhble burnt out, 

 and other crops cultivated on them for several years. 



Bacterial Disease of Maize. ^ 



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

 from some unknown disease, Burrill isolated Bacillus m-cnlrs. 

 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-grain, where 

 it may be epidemic. Prillieux- ascribes it to a Mierucoccva 

 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 I'ven cell-walls 

 had been dissolved. 



Mosaic Disease of Tobacco. 

 This disease of tlie tobacco is well known in the Xether- 

 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 influence of l)acteria, although 

 infection-experiments have hitherto failed ; other observations 

 on the disease do not confirm this conclusion. 



Potato-Rot.^ 



Ivuhn described a dry-rot or tuber-rot of the potato wliich 

 had been known since 1830. The disease appears generally 

 after harvest and lasts till spring. The tubers shrivel wy nnd 

 become very brittle. 



1 Burrill, Aijric. Exper. Station, Ciiir. of IUino{><, 1889. 



-Annah-< d. sci. natur., Ser. vi., 8, 1878, p. 248. 



»"lTeber tlie Mosaik-krankheit ties Tabaks," VersiichH-^tation, Vi.I. :V1, 1,S86. 



•* Kvihn, Die Krcuil-htitm d. Kidfiir<ii>nirh-<e, 18.58. 



The text-books of Frank ami Sorauer. 



Reinke and Bertholtl, Die ZerxetztiiKj d. Kartofel diirch Pih', ls79. 



Kramer, Oeslerreirli. lamhnrth. Cenlrafb/alt, 1891. 



