APPLICATION OF SULPHUR. 49 



are two methods of sulphuring vines : (1) The repressive method, 

 which consists in sulphuring each time the disease appears on a 

 certain part of the vine. That requires great attention on the part of the 

 vine-grower, who should not let the disease extend too far. (2) The 

 preventive method, which is most in use, consisting of three sulphurings 

 at fixed intervals. The first sulphuring is applied when as yet no oidium 

 has been observed at the time when the young branches reach 8-10 centi- 

 metres (3-2-4 inches) in length. The second at the time of flower- 

 ing, and the third some days before veraison, taking care to sulphur 

 the grapes chiefly. A supplementary sulphuring may be intercalated 

 between the second and the third if special conditions are favourable 

 to the reappearance of the disease at that moment. Dufour advises 

 two treatments before flowering, the first, before the complete expansion 

 of the leaves, the second a little before flowering. Spring sulphurings 

 in no way injure the plant, and they may be executed at any hour of 

 the day. But those which must be made in the hot season may in- 

 jure the vines, the leaves of which are burned by the sulphur under 

 the action of the sun. It is then necessary to comply with the follow- 

 ing indications : — 



(1) To use neutral sulphurs, chiefly mixtures, containing but little 

 sulphur, instead of flowers of sulphur, always slightly acid, and because 

 the former have a much more gentle action than pure sulphur. (2) 

 To spread the sulphur preferably on the soil, instead of projecting it 

 directly on the plant. This process is not only efficient, but without 

 the drawbacks described above (Viala). When these few precautions 

 are neglected, a large part of the crop is liable to be lost, owing to the 

 corrosive action of the sulphur. The dose to apply at each sulphuring 

 depends on the state of growth of the vine and the system of planting. 

 For the first treatment it is well to use 15-20 kilogrammes (33-44 lb.) of 

 flowers of sulphur per hectare (13'2-17"6 lb. per acre). At the time of 

 flowering the dose is raised to 30 kilogrammes of flowers of sulphur (66 

 lb. per hectare, 26-4 lb. per acre) or 50 kilogrammes (110 lb. per hectare, 

 44 lb. per acre) of ordinary ground sulphur. Finally for the third opera- 

 tion it is necessary to spread 40 kilogrammes of sublimed sulphur (88 lb. 

 per hectare, 35'2 lb. per acre) or 60-70 kilogrammes of ground sulphur 

 per hectare (52-8-61-6 lb. per acre) and about 100 kilogrammes of Apt 

 sulphur (220 lb. per hectare, 88 lb. per acre). When the ground sul- 

 phur is as fine as the sublimed, the quantity to use will be the same as 

 for the latter. To preserve hothouse vines, it suffices to spread sulphur 

 on the soil once a year ; any invasion is prevented by this single 

 treatment. Since other cryptogamic diseases — mildew, black rot, and 

 others — have ravished the vine, attempts have been made to reduce 

 the multiplicity of treatments, and cupric powders have been mixed 

 with the sulphur, the isolated action of which is recognized as effica- 

 cious against these diseases. It has been advised to add 5 per cent of 

 blue vitriol to the sulphur, or to incorporate sulphur in the cupric 

 bouillies. There is even on the market a preparation known under the 

 name of " cuprocalcite," which has in Germany the reputation of being 

 at 25° more active than sulphur (Mohr). This product would appear 

 to form a protective coat on the leaves, and by its adherence preserves 



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