152 EXPERIMENT STATION EECOED. [Vol. 37 



always justifiable from an economic standpoint. It is stated that in case of 

 much rainfall in spring a preventive treatment applied on the first indications 

 of an outbreak, and followed up as found necessary, is sufficient to control the 

 mildev?. In those localities where severe attacks appear annually, \^ith rare 

 exceptions, preventive treatment under competent scientific advice is considered 

 necessary. 



Vine mildew in Piedmont, Italy, in 1915, F. Maktinotti (Gior. Yin. Ital., 

 41 (,1915), No. 30, pp. 61S-615; abs. in Intemat. Inst. Agr. {Rome], Mo. Bui. 

 Agr. Intel, and Plant Diseases, 6 (1915), No. 9, p. 1261). — It is stated that 

 downy mildew, while showing variations with the locality and the portion of 

 the plant attacked, caused considerable losses in the vineyards of Piedmont in 

 1915. This was owing partly to rainy or damp weather and imperfect treatment 

 of the bunches, partly to lack of timeliness in spraying, and partly to the poor 

 quality of the sprays, as shown by analysis of samples of the materials era- 

 ployed. 



Treatment of downy mildew, A. Convergne and L. TKOucHAUD-VEatoiEB 

 (Rev. Vit., 45 {1916), No. 1149, pp. 9-11). — The authors have summarized the 

 principal conclusions arrived at regarding the treatment of downy mildew as 

 instituted in 1915 by the Agricultural Society of Gard. 



It is stated that the crop returns were usually to be gauged by the amount 

 of copper in the .sprays applied to the vines. Small proprietors obtained rela- 

 tively good results on account of the timeliness, thoroughness, and frequency of 

 the applications in such cases. Adherence and a sufficiency of copper content 

 proved to be important factors when washing rains were prevalent. 2 per cent 

 of copper being usually sufficient in such a period. Comparable results were 

 given by Bordeaux, Burgundy, and verdigris solutions when properly prepared. 



Sprays owe their immediate action to the presence of copper which is imme<li- 

 atoly soluble, and the efficiency of any spray depends upon its persistence In 

 soluble form on the leaf surface. The question as to how a spray can be pre- 

 pared that is both Immediately effective and durable is not regarded as having 

 been solved. Powders have been used with good effect after .spraying, when 

 applied before the surface become dry, but such treatments are regarded as 

 complementary only. Tlie minimum of sprayings required in normal years Is 

 about two, one about May 20 and the other about June 10. or just before and 

 just after the flowering period. Circura.stances will vary the requirements in 

 this re.spect as in others. 



Treatment of Oidium, J. Capus (Rev. Tit., 45 (1916), No. 1149, pp. 8, 9).— 

 Experimentntion has shown that grapevines when shielde<l from direct precipi- 

 tation are largely protected from downy mildew and black rot, but may be 

 severely attacked by Oidium. Treatment with powdered sulphur, while only 

 preventive in cases of the first two of these diseases, is also in a measure cura- 

 tive in case of Oidium, and decidedly so when the treatment is employed in 

 clear, warm weather, .soon after the outbreak of the disea.se. 



Fog and grape diseases, P. Larue (Rev. Tit., 4-^f (1916), No. 1145. pp. 411- 

 412). — Fog is said to increase infecti(Ui. particularly of grape downy mildew, 

 by favoring the adlierence of the infecting bodies to surfaces rendered le.ss re- 

 sistant or more favorable to their development. 



[Treatments for grape troubles], P. Causse (Rev. Vit., 44 (1916). No. 1145, 

 pp. 409-411)- — Besides giving a brief di.scussion of the hot-water treatment 

 for insects, the author states that he considers basic Bordeaux mixture prefer- 

 ;!ble for the treatment of grape downy mildew. Good results have been obtained 

 by treating vines showing court-nou6 with tar applied to wounds on the stock. 

 The growth was at fir.st backward and the vines looked sickly, but later they 

 attained normal color, growth, and yield. 



