350 EXPERIMENT STATION RECORD. 



eased beets and characteristics of the beet blight are discussed, nnd the possible 

 connection of this disease with certain bacteria is pointed out. In the dis- 

 cussion following the paper it was stated that only insects which have been in 

 contact with diseased beets are capable of transmitting the disease. 



[Leaf spot of wild celery] {Irish Nat., 23 (1914), No. 2, p. 48).— Mention is 

 made of the discovery by Pethybridge of a fungus on wild celery in the west- 

 ern part of County Galway, Ireland, thought to be identical with Septoria 

 petroselini apii of cultivated celery. It is considered improbable that the dis- 

 ease could have spread to the wild plants from cultivated ones. 



Inoculation studies are noted below. 



The possible source of origin of the leaf spot disease of cultivated celery, 

 G. H. Pethybeidge (Jour. Roy. Hort. Soc, 40 {1915), No. 3, pp. 476-480).— The 

 author reports that the fungus obtained from wild celery (see above), on which 

 it caused a mild form of disease, produced in cultivated celery effects re- 

 sembling in every way those of the well-known celery leaf spot. The reverse 

 test was impracticable as the wild plants were already infected. 



From this fact and a study of the parasite the author concludes that this 

 fungus is identical with Septoria petroselini apii of cultivated celery and may 

 be the original source of the infection, which is much more severe on culti- 

 vated than on wild celery. 



Pathogenicity and identity of Sclerotinia libertiana and S. smilacina on 

 ginseng, J. Rosemjaum {U. S. Dcpt. Agr., Jour. Agr. Research, 5 {1915), No. 7, 

 pp. 291-298, pis. 2, fig. 1). — A report is given of studies made on the white rot 

 of ginseng, previously attributed to S. libertiana (E, S. R.. 27, p. 649). and of 

 the black rot of gingseng, which has been reputedly caused by 8. panacis (EL S. 

 R., 27, p. 247). 



The pathogenicity of the species of Sclerotinia causing both of these dis- 

 eases has been estal)lished, and the one causing white rot is said to be identical 

 with 8. libertiana occurring on lettuce, celery, and a number of other host 

 plants. The fungus causing the black rot has proved to be identical with 8. 

 smilacina, inoculations from ginseng to the original host plant, Smilacina 

 racemosa, having given positive results. 



Studies of the Rhizoctonia disease of potatoes, J. H. CoKSAxn- {Abs. in 

 Phytopathology, 5 {1915), No. 5, pp. 293, 294; Science, n. ser., 42 {1915), No. 

 1086, pp. 582, 583). — An account is given of studies on the potato disease due 

 to Rhizoctonia in Oregon. AfiPected plants and tubers were secured from dif- 

 ferent localities and a large number of strains of the causal organism were 

 isolated. The cultural characters of these strains were similar, although some 

 variation was showTi. A number of varieties of potatoes were inoculated with 

 Rhizoctonia grown under similar conditions, and some varieties proved ex- 

 tremely susceptible while others were strongly resistant. This was also found 

 true when the fungus was grown on sterile plugs of raw potatoes. By arti- 

 ficial means healthy Rhizoctonia-free potato plants were made to reproduce 

 both the "aerial potato" and "little potato" conditions. These experiments 

 are thought to indicate that the abnormal effects are secondary results of 

 Rhizoctonia attack caused by interference with the normal process of food 

 storage in the plant. 



Diseases of sugar beets, O. Fallada {Osterr. TJngar. Ztschr. ZucJccrin<lus. u. 

 Landic, 44 {1915), No. 1, pp. 1-13). — This communication follows the same gen- 

 eral plan as that of the previous year (E. S. R.. 31, p. 543). 



Besides discussions of weather conditions and injurious animals, mention is 

 made of root rot, noted principally on the darker soils. Clasterosporium putre- 

 faciens in the leaves, and Phoina betas in both leaves and roots. 



