1017] DISEASES OF PLANTS. 753 



Strains of Rhizoctonia, .7. Kosenbaum and M. Shapavaxov {Abs. in Phyto- 

 patlioloffit, 7 (1917), No. 1, pp. 74, 75). — The authors report having isolated from 

 potato stems a strain of Rhizoctonia which had produced a girdling and hollow- 

 ing of the stems at or near the surface of the ground. Inoculation and culture 

 experiments with this organism revealed certain characteristics, and it is con- 

 sidered possible tliat different strains of Rhizoctonia may offer an explanation 

 for the conflicting reports regarding artificial infection. 



Will Spongospora subterranea prove serious in Virginia? J. A. McClin- 

 TOCK (Abs. in Phytopathology, 7 (1917), No. 1, p. 72). — As a result of planting 

 in Virginia potatoes affected with powdery scab, the author concludes that 

 powdery scab will not be prevalent either on the spring or on the fall planted 

 potatoes even though the seed tubers are infected with the organism. 



Host plants of Synchytrium endobioticum, A. D. Cotton (Roy. Bot. Gard. 

 Kew, Bui. Misc. Inform., No. 10 (1916), pp. 272-275) .—It is said to have been 

 proved beyond doubt that certain potato varieties are absolutely immune to 

 the wart disease organism, S. endobioticum. No varieties which appeared re- 

 sistant after thorough tests have broken down in this respect. 



Other plant hosts, however, have been discovered. A few minute sporangia 

 of the wart disease have been known to form on Solanum dulcamara and on S. 

 nigrum. It is thought that the latter constitutes a greater danger than the 

 former. It is considered as possible that the organism may have spread from 

 wild Solanums to potato in Hungary, where the disease is said to have been first 

 described. 



Bordeaux spray for tip burn and early blight of potatoes, K. T. Ebwir 

 (Iowa Sta. Bid. 171 (1917), pp. 62-75, pis. 2, figs. 6).— Results are given of five 

 years' experiments with tip burn and early blight of potatoes to determine 

 whether, under corn-belt conditions, these diseases can be dealt with profitably 

 by spraying with Bordeaux mixture. 



The author has found that three applications of Bordeaux mixture gave an 

 average annual increase of 10 bu. per acre, five applications 20 bu. per acre, 

 and seven applications 22 bu. per acre. Basing his conclusions on these results, 

 he recommends five sprayings with Bordeaux mixture, the first early in July, 

 the applications to be repeated at approximately 10-day intervals. 



A discussion is given of early blight and tip burn, their causes, temperature 

 relations, etc. 



Seed potato certifi.cation in Nova Scotia, P. A. Muephy (Abs. in Phyto- 

 pathology, 7 (1917), No. 1, p. 72). — A brief account is given of the method 

 adopt€Ki in Nova Scotia for producing seed potatoes for the Bermuda seed trade. 



Root disease of sugar cane, J. R. Johnson (Hacienda, 12 (1917), Nos. 4, PP- 

 117, 118, figs. 2; 5, pp. U6, H7, fig. i).— This is a discussion of the destructive 

 root disease of sugar cane, supposed to be caused primarily by Marasmius sac- 

 chari (though other fungi may be present), with suggestions for lessening 

 injury therefrom, including such measures as insect control, soil selection and 

 management, drainage, rotation, and resistance. 



Tobacco diseases and their control, J. R. Johnson (Hacienda, 11 (1916), No. 

 12, pp. S72-37Jt. figs. S; 12 (1916), Nos. 1, pp. 26-28, figs. S; 2, pp. 63, 64, figs. S; S, 

 pp. 91-93, figs. 2; 12 (1917), No. 4, pp. 124-126, figs. 2).— Descriptions are given 

 of several diseases, rots, or other sources of loss affecting the tobacco plant 

 during its life or preparation for storage or market. 



A CoUetotrichum leaf spot of turnips, B. B. ELiggins (TJ. S. Dept. Agr., Jour. 

 Agr. Research, 10 (1917), No. 4, pp. 157-162, pis. 2).— The attention of the 

 author, at the Georgia Experiment Station, was called in 1914 to a leaf-spot 

 disease of young turnip plants near Macon, Ga. The spots are said to be ^ in. 

 or less In diameter, circular in outline, and of a pale green or straw color. The 



