DISEASES OF PLANTS. 347 



which is a finely ground form of sulphur that has been recently placed on the 

 market. The results obtained from the use of these two forms of sulphur were 

 practically identical, so that there is little choice between them. One disadvan- 

 tage of the flour sulphur is its tendency to form into lumps, as this necessitates 

 thorough screening before its use. 



An account is given of tests of sulphuring machines, times for application, 

 amounts of sulphur to be used, etc. 



Diseases and enemies of peanut, A. Chevalieb {Jour Agr. Trop., IS (1913), 

 No. IJfl, pp. 72-76). — The author reports, along with various insect pests of 

 peanut in Senegal, a plant parasite which lives on the roots of this legume, 

 forming clumps from 15 to 30 cm. in height, considered to be closely related 

 to Alectra senegalensis and described under the name A. arachidis; also a 

 fungus, Septoglwum arachidis, thought to be probably identical with that other- 

 wise named Ccrcospora arachidis and C. per sonata. It is said to cause spot- 

 ting and fall of the leaves and to be most abundant in years of great humidity. 



Potato leaf roll due to necrosis of the pholoem, H. M. Quanjee {Meded. 

 Rijks Hoogere Land, Tuin en Boschbouwsch. [Wageningen], 6 (1913), No. 2, 

 pp. Jfl-SO, pis. 8). — As a result of several years' physiological and anatomical 

 study made on potatoes of several varieties affected with leaf roll, the author 

 concludes that potato leaf roll is not due to a specific organism, but that the 

 changes observed in the phloem of plants showing leaf roll are the result of 

 some slight chemical or physical disturbance in the cell, possibly connected 

 with illumination, transj^iration, and certain other factors, some of these 

 probably being hereditary. 



Silver scurf, a disease of the potato, I. E. Melhus (U. 8. Dept. Agr., Bur. 

 Plant Itidus. Circ. 127, pp. 15-24, fiffs. 4)- — Attention is called to a little known 

 disease of potatoes, which is becoming widespread in the United States. This 

 disease, called silver scurf, is caused by attacks of Spondylocladium atrovirens 

 on the tuber. In the early stages of infection the fungus causes blackish olive 

 patches on the surface of the potato, which often cover considerable areas. In 

 the later stages of development small black sclerotia are formed, and the surface 

 of the discolored areas takes on a silvery or glistening appearance, due to the 

 raising of the cells of the outer layers by the mycelium of the fungus. As the 

 disease progresses the infected areas increase and the fungus penetrates deeper 

 into the tuber. As a result often the whole surface of the tuber is discolored, 

 shrunken, and shriveled. 



For the control of this disease esperimenlfe with formalin and corrosive 

 sublimate treatments were carried on, in which at least double the ordinary 

 strength of these solutions used for controlling potato scab was employed with- 

 out destroying the spores of the fungus. Neither did dry heat at a temperature 

 of 50° C. for 5 hours kill the fungus. Further experiments are in progress to 

 test the possible value of formalin as a means of controlling this disease. 



A bibliography is appended. 



Fungus diseases liable to be disseminated in shipments of sugar cane, 

 Ethel C. Field (V. S. Dept. Agr., Bur. Plant Indus. Circ. 126, pp. 3-13, figs. 

 7). — A description is given of some of the more important diseases which are 

 thought liable to be introduced into this country through the importation of 

 sugar cane fi-om foreign countries. Among the diseases mentioned are the red 

 rot of the stem, iliau, gumming, smut, sereh, pineapple disease, Sclerotium 

 disease, and root and rind diseases. 



Red rot fungns and the sugar cane in the West Indies (Agr. Netos [Bar- 

 l)ados'l, 12 (WIS), Nos. 286, pp. 126, 127; 287, pp. 142, US; 288, pp. 158, 159).— 

 An account is given of experiments carried on by F. W. South and W. R. 

 Dunlop to reconcile some of the conflicting views to be found in literature 



