846 EXPERIMENT STATION RECORD. [Vol.40 



The blackleg 1 disease of cabbage caused by Phoma lingam, M. P. Henderson 

 {Phytopathology, 8 (1918), No. 8, pp. 379-431, fiffs. 10). — This disease, which is 

 said to be widely distributed in Wisconsin and to cause at times considerable 

 loss, may attack plants in the seed bed, the disease appearing in the field shortly 

 after transplanting. The fungus may attack the plants through leaf invasions 

 or through the roots. Stem infection often results in an elongated lesion ex- 

 tending from the roots to the leaves or it may girdle the stems and allow the 

 head to break off at the surface of the soil. Frequently nothing is left of the 

 plant but a blackened stump. In addition to the cabbage, quite a number of 

 other cruciferous plants have been inoculated with the fungus, while a few 

 species have been found nonsuseeptible under the conditions of the experiments. 



The fungus appears to be carried over in the seed, probably in the form of 

 dormant mycelium, and the most satisfactory treatment from the standpoint 

 of seed germination lias been found to be immersion for 20 to 25 minutes in a 

 1 : 200 solution of 40 per cent formaldehyde. This was found to kill the spores, 

 but was not sufficient to disinfect seed which had been invaded by the fungus 

 mycelium. The removal of diseased tissues from the soil and deep fall plowing 

 are recommended as means <>f control on infected fields. 



Physoderma disease of corn. W. II. Tisdale (Jour. Agr. Research [U. S.], 16 

 (1919), No. 5, pp. 137-154, pis. 10. fig. 1). — A detailed account is given of a study 

 made in the Bureau of Plant Industry, V. S. Department of Agriculture, of the 

 disease of corn due to P. tea* niaydis, the occurrence and distribution of which 

 have already been noted ( K. s. K., 38, p. 851). The history of the disease, its 

 distribution, economic importance, factors favoring its spread, etc., are de- 

 scribed, after which an account in given Of the causal organism, its germination, 

 host penetration, dissemination, etc. 



While no definite means of control have been discovered, there is considered 

 to be a possibility of preventing the disease by sanitation, rotation of crops, 

 and use of resistant varieties. 



A morphological and cultural note on the organism causing Stewart's dis- 

 ease of sweet corn, L. McCui.i.och (Phytopathology, 8 (1918). No. 8. pp. 440- 

 442, pi. 1). — According to the author, a study of the organism which has borne 

 the names Pseudumonas sti irartt and Bacterium tti toarti has shown that it is 

 improperly classified and should hear the name Aplanobaeter steirarti. 



Observations of cultures of this organism have shown that there are two dis- 

 tinct types of surface colonies as seen on peptonized beef agar plates. In viru- 

 lence, character of infection, general cultural characteristics, and morphology, 

 including the lack of flagella, the two types appear to be identical, the only 

 difference being the behavior of the colonies on the agar mentioned above. 



Bacterial oat blight, C. Elliott (Phytopathology, 8 (1918), No. 9, pp. 489, 

 490). — The author reports a severe bacterial blighting of oats in southern Wis 

 consin in 1918 and a similar condition in southern Minnesota, northern Illinois, 

 northern Indiana, and Ohio. The disease seems to be due to the organism pre- 

 viously described by Manns (E. S. R., 22, p. 453). 



In addition to the above blight, another distinctly different bacterial disease 

 was found on oats. This was first collected In June, 1917, at Urbana, 111., and 

 later at Lafayette, Ind., and at Wooster, Ohio. This disease differs from the 

 first in the absence of the halo effect on the leaves and the presence of an ex- 

 udate. To this latter disease the name stripe blight is tentatively given. 



Report of the conference on diseases of potatoes and seed certification. G. R. 

 Lyman et al. CWaxhinytnn: Wat Emergency lid. Amer. Plant Path.. 1918, pp. 

 1-20, pis. 2). — This is the report of the secretary to the conference held at 

 Buffalo, N. Y., August 16 and 17, 1918, on potato diseases, called for the con- 



