852 KXPERIMENT STATION RECORD. 



upon the germiDation of the spores of the black rot of grapes. As a 

 result of more tliau 4,000 experimeuts they found that acidity of the 

 culture medium favors germination of the spores, while an alkalinity 

 equivalent to 0.0001 sulphuric acid was able to comi)letely prevent it. 

 On this account the immediate effect of alkaline solutions of fungicides 

 will be much greater-than that of acid solutions. Copper was found 

 much less efficient against black rot than against mildew, and zinc had 

 about the same action as copper. Mixtures of copper and zinc gave 

 no better results than either used alone. Sulphur is without effect 

 when used alone, and may reduce the efficiency of copper solutions 

 when used in combination with them. 



Lavergne,^ who was commissioned by the Minister of Agriculture to 

 study the black rot in several of the vine-growing provinces, has made 

 an interesting report upon the subject. According to Marre,^ who has 

 investigated the preventive treatment of this disease, the efficiency of 

 copper solutions is clearly demonstrated; but to be successful the appli- 

 cations must be made frequently, beginning very soon after the com- 

 mencement of growth. Verdigris (acetate of coi^per) was the most 

 efficient fungicide, and should be used in 1 per cent solutions. The 

 experiments showed the good effect and profitableness of the treatment. 

 Lavergne and Marre^ have published a practical manual on the treat- 

 ment of black rot. This disease, which next to phylloxera is one of 

 the most destructive to grapes, has also been investigated by Prunet,* 

 of the University of Toulouse. He has demonstrated that the fungus 

 l)asses the winter in the form of sclerotia, the destruction of which 

 thus becomes very im])ortaut. Consequently burning all mummified 

 grapes is advised. 



Yiala and Ravaz'^ have studied the browning of grape cuttings, and 

 Tachoues'^ the brown rust of the grape and its treatment. J. d'Arbau- 

 mont ' has reported a curious development of a grapevine. A graft ui)on 

 a riparia stock sent out 3 branches the first year, 2 of which produced 

 normal fruit, while the other aborted some of its flowers. The flowers 

 were usually chloranthic in some of their organs, and the ovaries were ex- 

 tremely prolific. This variation has been fixed by cuttings and layers. 



Koze" has published numerous notes on potato scab. He has found 

 bacteria producing the disease in different varieties of jiotatoes, the 

 species of bacteria being named Micrococcus imperdtorifi^ M. alhidus, 

 i\m\ JLjiavidus.^ In a subsequent article '" the author suggests that 



' Bill. Min. Agr. France, 15 (1896), p. 285. 



" Ibid., p. 133. 



3 Paris : Masson, 1896. 



'Corapt. Rend., 122 (1896), p. 739. 



■Ibid., p. 1142. 



'■ Bui. Agr. Alger, et Tunis, 1896, p. 515. 



■ Bui. Soc. Bot. France, ser. 3, 3 (1896), p. 281. 



"Bill. Soc. Xat. Agr., 1896, No. 5. 



■'Conipt. Kcnd., 122 (1896), pp. 54.3, 750. 



'oCompt. Rend., 123 (1896), pp. 613, 759. 



