876 EXPERIMENT STATION RECORD. 



that if was no1 the true mosaic disease but was one commonly referred to by 

 growers as white rust It is claimed that other investigators have not dis- 

 tinguished between these two diseases, and hence the confusion regarding the 

 results of experiments. 



The writer believes that the white rust is of bacterial origin, while the cause 

 of the mosaic disease is still in dispute. The malformation and atrophy of the 

 leaves that characterize severe cases of mosaic disease are rarely met with in 

 France, the predominating characters being a uniform mottling of the younger 

 leaves into different shades of green. A similar coloring is noticed on plants 

 attacked by the white rust, except the areas are not so numerous and are more 

 definitely limited. In addition the rust spots are rarely observed on the young 

 leaves, but usually upon the older ones. 



In the true mosaic disease the discoloration spreads over the blade of the leaf 

 until it becomes of a uniform yellowish green color, the leaf finally drying up. 

 In the white rust the spots are limited by a brownish margin, which becomes 

 suberized, checking further spread. At the same time the center of the spot 

 becomes pale, more or less blanched, and dried. The organism has been isolated 

 and studied, its principal characters being described. 



The spot disease of Iwanowski (E. S. R., 6, p. 2.">4). the spotting of tobacco 

 leaves reported by Sturgis (E. S. R.. 11, p. Too), and the mosaic disease of a 

 number of authors are all believed to be different from the true mosaic disease 

 and identical with the white rust. The organism is believed to be undescribed, 

 and the name Bacillus maculicola is given it. 



A bacterial disease of cabbages, cauliflower, etc., G. Delacroix (Compt. 

 Rend. Acad. Sci. [Paris], 140 (1905), No. 20, i>i>. 1356-1358) .—The author states 

 that during the summer of 1904 numerous specimens of cabbage, cauliflower, 

 Brussels sprouts, etc.. were received which showed unusual coloration and 

 lesions on the petioles of the leaves and the bases of the stems. 



In a number of cases the disease appeared to have been arrested by the 

 formation of a cork layer about the affected spots, and in such cases lateral 

 buds developed but never attained marketable size. The disease seemed to be 

 most troublesome on soils that had a high nitrogen content, and it is believed 

 that this predisposed the plants to attack. 



From the diseased material the author isolated an organism, to which he has 

 given the name Bacillus brdssiewvorus n. sp. Cultures were made of the organ- 

 ism, and inoculation experiments showed that it was possible to produce the 

 disease in a number of vegetables related to the cabbage. Infection experi- 

 ments with filtered juice of the plants made at the same time produced lesions, 

 but did not develop the typical form of the disease. 



This organism is believed to be different from that causing bla'ck rot of 

 cruciferous plants or the bacterial disease recently described in Canada, 

 Bacillus oleracew (E. S. R., 16, p. 480). 



A fungus of the roots of the grapevine, L. Mangin and P. Viala (Compt. 

 Rend. Acad. Sei. [Paris], 140 (1905), No. 22, pp. 1477-1479 ) .—The authors 

 describe Stearophora radicicola, a fungus which was observed by them during 

 their studies on phthiriosis of the vine. 



This fungus seems to attack the roots of dead or dying vines where they have 

 been attacked by phylloxera, nematodes, etc.. and the fungus quickly completes 

 the destruction. The presence of the fungus in living tissues seemed to indi- 

 cate that it also played a parasitic role, but the authors are not yet prepared to 

 definitely determine this question. The fungus is technically described. 



Combined treatment for the prevention of downy and powdery mildew, 

 J. Mosse (Rev. 1/7.. 23 [l'.iurn. No. 600, pp. 6 o8-(?6 2 ).—Fov the prevention of 



