SULPHURIC ACID (OIL OF VITRIOL). 



87 



sorts of canker produced by the anthracnose containing spores which 

 should be considered as hot-beds of infection. The remedy most 

 generally used is a 50 per cent green vitriol solution, but to intensify 

 its action it is associated with sulphuric acid in the proportion of 1 

 to 2 per cent. Fifty kilogrammes, say 1 cwt., of green vitriol are 

 taken, and 1 litre, say 4 lb., of sulphuric acid are poured on to it 

 and the whole dissolved in 100 litres (22 gallons) of hot water. 

 However, many vine-growers limit themselves to sulphuric acid and 

 regard it as sufficient to circumscribe the disease. Bouchard, Debray, 

 Berlese, and McAlpine are unanimous in eulogizing the good results 

 of this method, which according to McAlpine is of current use in 

 AustraHa. It is certain that it kills not only the spores of this dis- 

 ease but also those of the oidium. It is important to operate before 

 budding-time, so as not to injure the growth. It is necessary to im- 

 bibe the stems, the runners, and all the wood, and even the eyes. The 

 latter, owing to this treatment, blossom, it is true, some days later than 

 non-treated vines, but this in many cases is an advantage. The coat 

 may be applied with a brush or with a woollen rag. 



Spharella Fr agar ice, Sacc. (strawberry leaf blight). — Galloway 

 recommends the following energetic treatment to destroy this disease : 

 Spray the strawberries after gathering the crop with 2 per cent acid, 

 which kills both the old leaves and the spores of the parasite. The new 

 leaves which spring up are perfectly healthy. Tyron found this treatment 

 to give as good results as bouillies bordelaise or alkaline sulphides. 



Guscuta (Dodder). — Wagenblicher found that O'S per cent acid killed 

 dodder, but when used on fields of trefoil and lucerne against Cuscuta 

 Ejnthymum the burning of the plant injured the crop. As a weed- 

 killer on walks sulphuric acid is defective. The effect is immediate 

 but the weeds soon sprung up as vigorous as ever. Finally, sulphuric 

 acid has been prescribed against potato scab. Wilfarth, acting 

 on the principle that ashes and lime induce this disease, tried to pro- 

 duce a contrary effect by spreading sulphuric acid on the fields. He 

 therefore spread sulfarine, a mixture composed of magnesium sulphate 

 and of 15 per cent sulphuric acid. The results were decisive, as shown 

 in the following table : — 



TABLE XIV. — Showing the Action of Different Doses of Siclfarine (kieserite) 

 containing 15 p??- cent of Sulphtirlc Acid on the Potato Disease. 



The disease is, in fact, considerably diminished by this treatment, 

 but the dose of 14 kilogrammes of sulfarine per square metre must 



