572 EXPERIMENT STATION RECORD. 



The researches of H. Marshall Ward on the brown rust on the bromes 

 and the mycoplasm hypothesis, J. Eriksson ( Ark. Bot., 1 (1903), No. IS, pp. 139- 

 146). — The author reviews and criticises the investigations of Marshall Ward on the 

 rusts of brome grasses which have been published within the last few years. 



He differs with Marshall Ward in the interpretation of some of the results given 

 and defends the hypothesis, which is now referred to as the mycoplasm hypothesis, 

 claiming that in addition to the 2 forms of infection by uredospores and fecidiospores 

 we must recognize a direct infection by teleutospores without the intervention of an 

 gecidial stage or from a latent germ of disease inherited from the parent plant, con- 

 cealed in the seed sown, or in the case of perennial species in the stolons growing 

 forth in the spring. Both of these methods of infection presuppose a period of incu- 

 bation of from 2 to 10 months. 



A soft rot of the sugar beet, H. Metcalf ( Nebraska Sta. Rpt. 1903, pp. 69-112, 

 figs. 6). — An extended account is given of asoft rot of thesugar beet which the author, 

 together with G. G. Hedgcock of this Department, has previously noted (E. S. R., 

 14, p. 1085) . The disease is due to bacteria, the general characters of the disease 

 being described and its distribution noted. 



An account is given of inoculation experiments on sugar beets and other vegetables, 

 it being readily demonstrated that the disease is produced by the organism. In 

 addition to sugar beets the bacterium made a slow growth on garden beets and a 

 slight growth on carrots and sweet potatoes, but did not spread much from the point 

 of inoculation. Onions, hyacinth bulbs, and parsnips, inoculated in December, 

 1901, gave no infection, but when the experiments were repeated the following 

 spring the rot spread to a slight extent. On potatoes, turnips, radishes, tomatoes, 

 and apples no growth occurred. 



The cause of the disease is attributed to Bacterium leutlium, and the morphological 

 and general characters, as well as its cultural characters, are described at length. 

 So far as the author's investigations are reported there has not been sufficient field 

 work to demonstrate the general distribution of the disease, but it is believed that it 

 may prove quite serious in restricted localities. In order to prevent the disease the 

 author recommends growing beets on relatively dry ground, and the roots should be 

 well dried and sunned before put in storage. If these precautions are followed there 

 will probably be little loss due to this cause. 



Blackleg or potato stem rot (B<1. Agr. and Fisheries [London], Leaflet //,", pp. 

 3, Jigs. 2).— An account is given of a disease of potatoes caused by Bacillus phytoph- 

 thorus, a previous account of which has been given (E. S. R., 15, p. 374). ■ There is 

 said to be reason to believe that the disease is spreading in Europe, frequently caus- 

 ing 10 to 15 per cent loss, and sometimes as much as 75 per cent of the entire crop is 

 destroyed. The suggestions for the control of the disease are rotation of crops, plant- 

 ing of whole tubers, care in obtaining seed tubers from uninfested regions, and the 

 avoidance of the use of lime or strong nitrogenous manures. 



Club root of cabbage, H. Vanderyst (Bui. Agr. [Brussels'], 20 (1904), No. 4, pp- 

 533-567, figs. 9). — An investigation was conducted by the department of agriculture 

 on the occurrence and distribution of the club root of cabbage, due to Plasmodiophora 

 brassier. In carrying out this investigation letters were addressed to a large number 

 of horticulturists, agriculturists, cultivators, and others, asking for information regard- 

 ing the distribution of this disease, the influence of various factors on its develop- 

 ment, etc. 



From the replies obtained the article is compiled and it is shown that the disease 

 is well distributed throughout the agricultural portion of Belgium. There seems to 

 be a very evident relationship between the frequence of occurrence and destructive- 

 ness of the disease, and the chemical composition of the soil and method of cultiva- 

 tion. It has been known from time immemorial in the sandy soils of Flanders and 



