194 INSECTICIDES, FUNGICIDES, AND WEED KILLERS. 



servative action is inferior to that of cupric derivatives. Sbrozzi's 

 trials in 1900 confirmed this conclusion. Guocdenovic in 1900 made 

 comparative experiments with 0'25, 0"5, 0"75 per cent copper bouillies 

 and with nickel h^'drate bouillies, made like bouillie bordeiaise wth 

 0"25, 0".j, and 1 per cent of nickel sulphate. The action of these 

 bouillies was identical. The 0*25 per cent nickel hj-drate bouillie was 

 still active, and more effective than the bouillie bordeiaise with 0"2o 

 per cent of blue vitriol. He concluded that nickel bouillie could 

 perfectly well replace bouillie bordeiaise against this fungi. 



Botrytis cinerea, Pers. (grey I'ot of the vine). — Viala and Gouirand 

 made interesting researches on the comparative action of nickel and 

 copper sulphates on this redoubtable fungus. According to the experi- 

 ments copper salts have little action on the germination of the Botrytis. 

 Whilst the spores of Peronospora viticola are killed in a solution of 

 3 parts in 10,000,000 of blue vitriol, it takes a 5 per cent dose of blue 

 vitriol to prevent the germination of Botrytis cinerea. It is not so 

 with nickel sulphate which is 40 times stronger than blue vitriol. 

 In a solution of 2 parts per 10,000 the spores are almost entirely 

 prevented from germinating. Nickel carbonate has shown the same 

 superiority as compared against the Burgundy bouillie, for whilst it 

 takes a 7*5 per cent cupric bouillie to prevent all spores from germin- 

 ating in sixteen hours, a 1 per cent nickel bouillie has the same 

 effect. The results, repeatedly verified, have always been the same. 

 Experiments on the large scale against grey rot do not appear to have 

 been made as a sequel to the laboratory experiments of Viala and 

 Gouirand. Is it because aluminium sulphate, much cheaper, produces 

 equally good results ? 



78. Cobalt Sulphate, C0SO47H0O. — It was purely of scientific in- 

 terest to investigate the action of cobalt salts on plants and parasitic 

 fungi, for these salts are too dear to be used on the large scale. Cobalt 

 sulphate was tried comparatively against nickel sulphate and blue 

 vitriol by Eichards. Its action on plants was found to be analogous 

 to that of the two latter salts, stimulating in small dose, poisonous 

 in larger doses. The experiments of Aso, Nakamura, and Suzuki, 

 on Allium, Brassica chinensis, Hordeum, and Pisum, enable us to con- 

 clude that its stimulating action is not very decided. 



