1019] DISEASES OF PLANTS. 347 



to be a weak parasite and able to Lnfecl healthy (issues only trader the most 

 favorable conditions. 



Rhizoctonia in jute: The inhibiting effect of potash manuring, It. S. I'in- 

 i.ow (Af/r. Jour. India, Indian Sci. Cong. No., 1918, pp. 65-72). — Indications 

 having been noted that a connection may exist between the presence of 

 Rhizoctonia and a lack of potash In the soil, the author b:is taken part in 

 preliminary experimentation, which as here described is considered to show a 

 highly beneficial effect ascribed to tbe potash content of the ash of water 

 hyacinth. 



Potato diseases. — I, Early blight or leaf curl, Ethel M. Domes (So. African 

 Fruit Grower, 4 (1917), No. J. i>p. 65-67, figs. 5). — Experiments on early blight 

 carried out for three years on an extensive scale on several varieties of 

 potatoes at Groenkloof, near Pretoria, showed no very satisfactory results for 

 either Bordeaux or Burgundy mixture. The better results were obtained with 

 the former, the latter causing some injury to the plants, which showed con- 

 siderable varietal differences as regards susceptibility. 



Leaf roll of potato, Blanchakd and Perret (Compt. Rend. Acad. Agr. France, 

 8 (1917), No. 81, pp. 894, 895). — This is a summary of a report on studies with 

 potato leal' mil carried on since 1914 in the Department of the Loire. 



Although the cause of the trouble has not been definitely established, it 

 appears not to be due to parasitic agency but to physiological and other 

 causes, probably being connected with too long a course of asexual reproduc- 

 tion and with too great n deficiency of nitrogenous factors in the soil. Certain 

 varieties named appear i<> possess resistance to leaf roll. Copper treatments 

 were without beneficial effect. 



Determination of the factors inducing leaf roll of potatoes, particularly in 

 northern climates, P. A. Murphy and E. .1. ^A'okteey (Phytopathology, 8 (1918), 

 No. 4, pp. 150-154, fig. 1). — The authors, in a first progress report on leaf roll, 

 confirm the claim of Quanjer that leaf roll may be transmitted to healthy 

 potato plants grown in proximity to diseased ones (E. S. R., 36, p. S47). 'the 

 history of a number of potato plats in Prince Edward Island is given and the 

 development of the disease in these plats is traced. 



As a result of their investigations, it is claimed that it is impossible to rid 

 stock of leaf roll by the selection of healthy potatoes, even when only a mod- 

 erate amount of the disease is present and the work is carried on under con- 

 ditions unfavorable to the production of the disease. It is recommended 

 in case of collections of varieties of potatoes that they should be grown in 

 rows separated from one another by at least G ft., and that the intervening 

 space should be planted with some other hoed crop. 



Sweet potato storage rots, L. L. Hartee, J. L. Wkimku. and J. M. K. Adams 

 (Jour. Agr. Research [U. S.J, 15 (1918). No. 6. pp. .187-868, pis. 7).— This ar- 

 ticle, which is a contribution from the Bureau of Plant Industry. U. S. Depart- 

 ment of Agriculture, is an elaboration of a report previously published I B. S. 

 R., 39, p. 854). 



Seventeen fungi responsible for loss in sweet potatoes in storage are 

 described at considerable length. Of these. Rhisopus nigricans. Bphteronema 

 flmbriatum, Diplodia tubericola, Diaporthe batatatis, Plenodomua deatrut 

 Sclerotium bataticolo, and Monttochcetes infuscans are said to be responsible 

 for most of the loss, while under favorable storage conditions rots may be 

 produced by Minor racemosus, Mtcnxiria sp.. Penicittium sp.. Botrytifi citurca, 

 Epicocoum sp., Gibbcrclla saubincUii. Fusariuin cuhnorum, /•'. acuminatum, 

 and Triehodcrma koningi. Some of the organisms causing storage rots are 

 also known to cause field diseases of sweet potatoes. These are Spha;roncma 

 flmbriatum, Plenodomus destruens, and MonVochcctcs infuscans. 



