DISEASES OF PLANTS. 1 1 iu\ 



[German Summary], pp. 1 ; 14). The author investigated the effect of time of seed- 

 ing on smut production, Beed treatmenl with fungicides, and varietal resistance. No 



striking differences could be noted in the ai mi of Bmul thai could be attributed to 



the time of seeding. 



In the experiments for Beed treatmenl the effecl of hot and cold ashes, dry air, 



cold water and milk of li Bordeaux mixture, hoi water, copper sulphate solutions, 



Formalin, and corrosive sublimate solutions were tested. All the treatments reported 

 diminished the germinative ability of the wheal to some extent, the least injury 

 reported being with the lots of seed treated with 0.1 per cenl formalin, followed 

 closely by the lot soaked for 5 minutes in Bordeaux mixture. The seed of the 

 differenl lots was aown and counts made -it' all smutted stalks and heads. 



Practically all smut was prevented by the treatments with Bordeaux mixture, 

 formalin, and 0.5 per cenl copper sulphate solution, each treatmenl being aboul the 

 same in efficiency. Mixing the -rain with drj ashes immediately after thrashing 

 was next in efficiency, only :;.;> per '-nit ,,1' the plants and i'."> per cent of the heads 

 being smutted. 



Marked differences in varietal susceptibility are noted. 



Investigations on the mosaic disease of tobacco, 1 ■'. \V. T. Hi ngeb [Ztschr. 

 Pflanzenkrank., 15 1 1905), No. 5, pp. 257-811, fig. I).- A review is given of the vari- 

 ous theories regarding the cause of the mosaic disease, particular attention being 

 given the bacterial theories of Mayer, [wanowski 1 E. S. II. . 13, p. 361 |, and Prillieux 

 and Delacroix 1 E. S. R., •">. p. 1019), and the theories of Beijerinck E. 3. EL, 10, 

 p. 1058), and Woods I E. S. R., 13, p. 1 16; I 1, p. 264 . after which the author si 

 and elaborates his theory regarding the causes of this disease. 



According to the author's view any disturbances in the normal metabolism of the 

 plant may result in the variegation characteristic of the mosaic disease. He holds 

 thai the immediate cause of the disease is an unorganized fermenl of the toxophore 

 -roup of Oppenhehner rather than oxidizing enzyms, as proposed by Woods and 

 others. The mosaic disease must not be confused with variegation as it occurs in 

 ornamental plants, which has been shown to he a nol infrequent phenomenon in cer- 

 tain species of Nicotiana. It is also said to differ from the disease described by 

 Sturgis under the name "calico" (E. S. R., 11, p. 7 



Some of the factors favoring the mosaic disease are described and the results of 

 investigations on meteorological conditions and >oil< in Java are given. A bibliog- 

 raphy of literature relating to this subject completes the article. 



Combating the mosaic disease of tobacco, II. Jensen [Centbl. Bakt. [</<•.], '. 

 Abt. t i~> (1905), No. 13-14, pP'440-44o). — In commenting upon the possibility of 

 combating the mosaic disease through breeding experiments, the author briefly 

 describes an experiment which he thinks Bhows the impossibility of producing 

 resistant races within a single year, as has been claimed by other.-. 



The author believes it will he possible to develop resistant varieties, but that it 

 will be found iiest to work with resistant races, within varieties of known quality, 

 rather than attempt to develop new type.- whose chief recommendation is hard; 

 or resistance. 



Potato diseases, T. W. Kirk [New Zeal. Dept. Agr. Ami. Rpt., /•>' 

 846-86S, pis. 6, figs. ?).- -A brief account i- '_ r i\en of spraying experiments which suc- 

 cessfully reduced the percentage of loss due to various potato diseases, and descrip- 

 tions are given of the following diseases of potato,-: Late blight (PhytopfUhora 

 infestan8 l, early blight or leaf curl | Macrosporium solani |, bacteriosis 1 Bacillus sokma- 

 cearum), scab (Oospora scabies), dry rot (FusarixJan oxysporum),& wet rot which is 

 believed to be of bacterial origin, and brown spot, which is of an uncertain cause. 

 Where known, suggestions are offered of means tor preventing these diseae 



Note on the facultative saprophytism of Alternaria solani, A. 1 1. ( loCKATNI 

 {New Zeal. Dept. Agr. Ann. Rpt., . -480) > — A report is given of a 



