DISEASES OF PLANTS. 487 



The occurrence of the disease is indicated by the appearance on the leaves of intensely 

 red spots of varying size. These increase, destroying the chlorophyll activity of the 

 affected portions of the leaves, and ultimately destroy the whole leaf blade. Some- 

 what similar appearances are said to be produced by a number of agencies, and the 

 different causes are pointed out for each disease. 



The cause of the red scald or red burn of the leaves is a fungus {Pseudopeziza trachei- 

 phila n. sp. ), which attacks the veins of the leaf, filling the conductive tissues with 

 its hyphie. The organism has been isolated and cultivated, and a diagnosis of its 

 principal characters is given. Unfavorable soil and climatic conditions for grapes 

 favor the rapid spread of the disease, and draining is recommended to prevent too 

 much soil moisture. Spraying with Bordeaux mixture has given good results in the 

 protection of plants from this disease. 



Resistance to cMorosis, J. M. Guillon and O. Brunaud {Her. VlL, 20 {1903), 

 Nos. 513, pp. 437-441; 516, pp. 532-535, pi. 1). — The results are given of a study of 

 different varieties of grapes, in which the relative resistance to chlorosis was deter- 

 mined. The authors adopted a scale of resistance and have noted the points of 

 resistance, from 1 to 20, for a large number of species and hybrids, particular atten- 

 tion being given to the hybrids of the cinerea, Arizonica, candicans, cordifolia, and 

 aestivalis grapes. 



Among the European species Vitis vinifera is one of the most resistant, and among 

 the American introductions V. herlandieri, is most resistant to this disease. The 

 hybrids between these species are also found to be quite resistant. The rupestris 

 and rijiaria hybrids are much more subject to attack tlian the others described. 



Tlie bacteriosis of roses, G. Scalia {Agr. Calabro Siculo, 1903; ahs. in Bot, 

 Centbl., 93 {1903), No. 34, p. 194)- — A preliminary note is given of a tuberculous dis- 

 ease of roses, which has been observed in Catania, attributed to the action of bac- 

 teria. The author has isolated a number of organisms, one of which seemed to be 

 (juite constant in its occurrence and character, and for this the provisional name 

 BdcUIm romnuii is given. It is proposed to study the subject further. 



A bacterial disease of sugar beets, G. G. Hedgcock and H. Metcalf {ZUchr. 

 Pfanzenkrank, 12 {1902), No. 6, pp. 32 1-324). —In the abstract of this article (E. S. E., 

 14, p. 1085) the bacterium should have been described as not growing upon dextrose 

 gelr.tin and only slightly, if at all, upon potato, and as producing no color or gas, in 

 contradiction to the organism described by Kramer. 



Diseases of chrysanthemums, G. E. Stone {Amer. Florist, 21 {1903), No. SOS, pp. 

 583, 584) • — The effect of heat, moisture, light, and the circulation of air as factors 

 in diseases of plants grown under glass are discussed, after which special attention is 

 given to the diseases of chrysanthenuims. The powdery mildew, rust, and stem rot 

 are described, the rust and stem rot Ijeing reported as the most troublesome. Anthrac- 

 nose of chrysanthemums and 2 forms of leaf spot are briefly mentioned, and in con- 

 clusion the author states that cultural methods rather than remedial treatments 

 should l>e adopted in com])ating plant diseases in greenhouses. 



The chrysanthemum rust, E. Jacky {Centbl. Bakt. u. Par., 2. Abt., 10 {1903), No. 

 12, pp. 369-381, figs. 8). — In the author's previous report of studies on the rust of 

 chrysanthemums (E. S. R., 13, p. 153) the identity of the fungus Puccinia chrysan- 

 theini and other forms was discussed, and this species was considered different from 

 P. tanaceti in its mor])hological and j)hysiological characters. 



The form occurring in Japan and lately described as P. chrysantheml ckinetms is 

 reported upon in the present paper. Inoculation experiments with Japanese mate- 

 rial showed that the rust is a Ilemipuccinia and is capable of invading Chrysanthe- 

 rnum iiuUrum, as well as its usual host, C. chinense; and it appears to differ from the 

 usual form of P. chrysanthemi mainly in the character of its teleutospores. 



The author has investigated the question of varietal 2>redisposition t(j rusts, and so 



