450 EXPERIMENT STATION RECORD. [Vol.40 



causal organism of cucumber angular leaf spot may overwinter in the seed 

 and cause infection, the authors confirmed by field tests the accuracy of these 

 observations, and they report upon the efficacy of seed disinfection as a control 

 measure. 



It is claimed that outbreaks of angular leaf spot may originate from contami- 

 nated seed or infected soil, and that seed disinfection reduces the incidence of 

 the disease nearly one-half. The use of treated or disease-free seed in fields 

 well removed from previous cucumber patches is recommended as a control 

 measure. For seed treatment, Immersion in a 1 : 1,000 corrosive sublimate solution 

 for 5 minutes, followed by 15 minutes' washing, proved most satisfactory from 

 the standpoint of safety and effectiveness, this treatment having been used on 

 a commercial scale in 1918. 



Copper sulphate as a disinfectant for potatoes, G. R. Bisby and A. Q. Ton 

 (Phytopathology, 8 {1918), No. 5, pp. ,i',n. .",!).— The results of three years' 

 treatment of potatoes with copper sulphate BOlntlons as a disinfectant are given. 

 Seed tubers Infected with black scurf were used to compare the efficiency of 

 copper sulphate, corrosive sublimate, formaldehyde, and lime-sulphur. The 

 tubers were planted at University Farm, Minn., in rather acid soil, and the 

 results were fairly consistent in that the best average yield was obtained from 

 seed treated with copper sulphate. 



Two Illinois rhubarb diseases, F. I.. Si i:\kns (Illinois sin. Bui. 219 (1919), 

 pp. 298-312, figs. 19). — Descriptions ate given of anthracnose and leaf spot of 

 rhubarb. 



The anthracnose. which Is said to be due to Colletotrichwn cnunpcns, was 

 first noticed on market rhubarb in the stores of Champaign, 111., lu 1918. The 

 fungus causes a soft rot of the petioles, the decayed spots usually being - 

 watery, translucent, and oval in outline, with the long axis lengthwise of the 

 petiole. In the market only milder cases of the disease were found, but in the 

 field in the more advanced atages the older petioles were dead and the yield of 

 marketable product was considerably reduced, in addition to the original 

 locality, the disease has been observed in a number of other places in Illinois. 

 The fungus has been Isolated and its cultural characters are described ;it con- 

 siderable length. 



The leaf-spot disease, which is said to be due to Phyllotticta utramimlhi. was 

 first collected in Kankakee County, 111., where It occurred in greal abundance 

 in one field, nearly every leaf in the planting being affected with spots. Unlike 

 the anthracnose, the leaf spot is nol a disease of old leaves, as even the com 

 paratively young leaves may be seriously affected. In addition to affecting the 

 leaf blade, the disease has also been found on the petioles. The leaf spot is 

 said to have been observed not only in several localities in Illinois, but also in 

 Indiana and Wisconsin. 



Physiological studies of normal and blighted spinach, R. II. Trie kt ai. 

 (Jour. Agr. Research [U. 6.], 15 (1918), No. 7. pp. S69 -408).— The results are 

 given of laboratory studies from the Bureau of Plant Industry of the F. S. 

 Department of Agriculture on normal and blighted spinach plants as contribut- 

 ing possible explanations regarding spinach blight The papers presented are: 

 Ash Content in Normal and in Blighted Spinach, by R. H. True. (>. F. Flack. 

 and J. YV. Kelly; Oxidase Reaction in Healthy and in Blighted Spinach, by 

 H. H. Bunzell; Carbohydrate Production in Healthy and in Blighted Spinach, 

 by R. H. True and F. A. Hawkins; and Nitrogen Metabolism in Normal and in 

 Blighted Spinach, by S. F. Jodidi, F. II. Kellogg, and R. H. True. 



In the study of the nsh content, it was found that, while the quantity of total 

 ash is not strikingly different in normal and in diseased material, normal tops 



