150 EXPERIMENT STATION EECOED. 



Experiments relating" to the control of potato scab, G. E. Stone and G. H. 

 Chapman (Massachusetts Sta. Rpt. 1912, pt. 1, pp. 84-96, pi. 1). — The results 

 of experiments with various chemicals for the prevention of potato scab are 

 given. These experiments were begun in 1908 and continued for 4 years, dif- 

 ferent substances being employed. The potatoes were grown in soil in tiles 

 23 in. in diameter, and the treatment consisted of sterilization and the use of 

 formalin, potassium permanganate, sulphuric acid, sulphur, copper sulphate, 

 carbon bisulphid, a commercial by-product called by the author "by-product 

 A," etc. 



Summarizing the results of the experiments, it is shown that many of the 

 substances used had little effect in preventing scab, while others seemed to pos- 

 sess some value. Steaming the soil seemed to have but little effect on the pro- 

 duction of scab. The best results were obtained by the use of by-product A in 

 dry form, followed by sulphur treatment and by-product A in solution and 

 steam heating. The by-product seems to act slowly and continuously as a 

 germicide, and it is thought that it may prove efficient in the control of other 

 fungi. 



The relation of cane cultivation to the control of fung-us diseases, J. R. 

 Johnston (Porto Rico Sugar Producers' Sta. Circ. 3 (English Ed.), pp. 13). — 

 The author describes the various cultural methods that have been tested for 

 growing cane, and points out methods to be adopted for the control of fungus 

 diseases so far as any relation exists between them and the agricultural prac- 

 tices. 



The black rots of the sweet potato, J. J. Taubenhaus (Phytopathology, 3 

 (1913), No. 3, pp. 159-166, pis. 3).— A study of the black rot of the sweet potato, 

 described by Halsted (E. S. U., 2, p. 416) and since attributed to Sphceroneina 

 fimT)riatum, has been made, and the author has come to the conclusion that the 

 disease is not due to this species, but is a sclerotium fungus, to which the name 

 Sclerotium 'bataticola n. sp. is given. In order to distinguish this disease from 

 the black rot caused by Trichoderma komngi, it is proposed to call it the char- 

 coal rot of the sweet potato. 



A third black rot of the sweet potato is described, which is said to be due to 

 Lasiodiplodia tuhericola. For this the author proposes the name Java black 

 rot, as this indicates the source from which the disease was first obtained. 



Study of recent diseases of grapevines, their importance and treatment, 

 V. C. M. DE ZtJNiGA (Estac. Enol. Earo Mem., 1912, pp. 85-98).— Giving the 

 results of several years' study of arrepollao or achaparrado (court-noue) of 

 grapevines in the Rioja, Spain, the author states that this trouble although not 

 very serious at present is more frequently met with on lowlands and levels and 

 in valley bottoms than in higher portions of the valleys and on benches. 

 Clayey, cold, compact soils appear to favor court-noue more than do loose stony 

 or slaty soils, the percentage of moisture seeming to bear some relation to its ap- 

 pearance as do also abrupt temperature changes in winter and spring. Con- 

 siderable differences are noted in the susceptibility of different varieties, Riparia 

 and Berlandieri proving relatively resistant. It is thought also that vigorous 

 growth in autumn tends to decrease the likelihood of this trouble in spring. 



Downy mildew in Vaucluse in 1913, E. Zacharewicz (Rev. Vit., 40 (1913), 

 No. 1025, pp. 171-174)' — Three outbreaks of downy mildew were noted in the 

 Department of Vaucluse in 1913. Both copper sulphate mixed with powdered 

 soap to the amount of 1.5 per cent each in water, and a mixture of 70 parts of 

 sulphur with 30 parts of 20 per cent sulphosteatite, were used soon ^ after rains 

 with good results, as also was a treatment of powdered lime 55 parts, 20 per 

 cent sulphosteatite 40 parts, and naptha soap 5 parts, all these treatments be- 



