650 EXPERIMENT STATION RECORD. 



diseases described are Alternaria blight, Phytophtliora mildew, Vermicularia 

 stem anthracnose, Pestalozzia leaf antbracnose, papery leaf spot, injury caused 

 by cold following the use of Bordeaux mixture, the damping off of seedlings 

 due to Rhizoctouia, Pythium, etc., wilts due to Acrostalagmus and Fusarium, 

 nematode root galls, and root rots due to a number of causes. The spraying of 

 ginseng, soil sterilization, relation of fertilizers to diseases, and the drainage of 

 ginseng beds are also discussed. 



An external dry rot of potato tubers, Miss C. O. Jamieson and W. H. Wol- 

 LENWEBER (Joiir. WasJi. Acad. Sci., 2 (1912), No. 6, pp. 146-152, fig. 1 ; alts, in 

 Mycol. CentbL, 1 {1912), No. 6, p. 180). — A Fusarium was found on potatoes 

 affected with dry rot which was proved by inoculation experiments to be a 

 wound parasite capable of causing this disease. The fungus is claimed to be 

 a new species, distinguished by its two forms of conidia, and is described 

 by the authors under the name F. trichothecioides n. sp. It claimed that 

 the disease is clearly differentiated from the wilt and dry rot ascribed to 

 F. oxyspornm. 



The relationship of Oospora scabies to the higher bacteria, G. C. Cunning- 

 ham {Ahs. in Pliylopathology, 2 (1912), No. 2, p. 97). — A study of cultures of 

 the organism causing the potato scab has led to the conclusion that the organism 

 should be placed in the genus Streptothrix, one of the higher bacteria. 



Biocheniical research on leaf-roll of potato. — III, Chemical characters, G. 

 DoBY (Kis6rlet. Kozlem., 15 (1912), No. 2, pp. 210-222; Ztschr. Pflanzenkrank., 

 22 (1912), No. Ji, pp. 20^-2ii).— Further analyses (E. S. R., 26, p. 547) lead the 

 author to conclude (1) that the chemical composition of tubers affected with 

 this disease shows different variations from those observed in the case of sound 

 ones, but that the limits of such variations are as yet diflicult to determine 

 on account of complications arising from such influences as soil, weather, va- 

 riety of potatoes, etc. ; (2) that the diseased tubers show a lower average in dry 

 substance, ash, protein, and carbohydrates as a whole; (.3) that the sound and 

 diseased tubers differ most in the total and the composition of their dry sub- 

 stance and in starch; and (4) that the biochemical processes are more retarded 

 in diseased than in sound plants, but that it is probably not yet practicable to 

 distinguish diseased potatoes on the basis of chemical analyses alone. The 

 results are given in tabulated form. 



Treatment of seed potatoes with formalin (Agr. Oaz. N. S. Wales, 23 (1912), 

 No. 5, p. JfOS). — In an experiment at the Bathurst Experiment Farm, seed pota- 

 toes treated with formalin to prevent the development of scab and other diseases 

 were practicallj^ a failure, while plats of untreated seed germinated well. 



Gummosis, L. P. de Bussy (Meded. Deli-Proefstat. Medan, 6 (1911), No. 2, 

 pp. 77-89). — An account of studies carried on during 1910-11 on gummosis of 

 tobacco. 



This disease is claimed to be caused in case of the plants studied by Bacillus 

 solanaceariim, which is alleged to attack also other plants. Artificial inocula- 

 tions, it is stated, de\eloped infection in case of potato, indigo, sesame, tomato, 

 and other economic plants. The details are given of investigations carried out 

 on the influence of cultivation and manuring on the progress of the disease. 



The Deli form of Bacillus solanacearum, J. A. Honing (Meded. Deli-Proef- 

 stat. Medan, 6 (1912). No. 7, pp. 2/9-2.50).— This is a detailed account of the 

 author's studies on the morphological and physiological characters of B. solana- 

 cearum, claimed to cause gummosis of tobacco and other plants at Medan, and 

 a detailed comparison of these characters with those of B. nicotiana;, said to 

 cau.se a like disease of tobacco in Japan. The conclusion is reached that the 

 two properly belong to the same species, the former being probably a somewhat 

 weakened form of the species. 



