168 INTERNATIONAL CONGRESS OF VITICULTURE 



sulphid, precipitated sulphur, and calcium sulphate. After a slight excess of 

 lime-sulphur solution has been added, the barrel should be filled with water 

 and the contents stirred thoroughly, and allowed to stand for several hours. 

 The black iron-sulphid mixture will settle into the lower half or third of the 

 barrel and the clear liquid should be poured off by carefully and gradually 

 tipping the barrel, without allowing any of the black precipitate to run out. 

 The barrel should again be filled with water, the contents thoroughly stirred 

 and allowed to stand several hours, and the clear liquid poured off as before. 

 This operation of washing the precipitate should be repeated until the water 

 poured off no longer shows the yellow lime-sulphur tinge. Probably three or 

 more such washings will be required, depending upon how careful the 

 operator has been in using only a slight excess of lime-sulphur solution. 

 When the washing has been completed, the stock barrel should be filled with 

 water to exactly fifty gallons. . . . care should be taken to stir the con- 

 tents of the barrel thoroughly each time before any of the mixture is taken 

 out." 



The finished spray was made by taking 20 gallons of the stock solution 

 and adding water to make 200 gallons. The cost of the spray is estimated 

 not to exceed fifteen or twenty cents per 100 gallons. 



This paste mixes readily with water, is entirely insoluble therein, re- 

 mains well in suspension, adheres to foliage, and has given excellent results 

 in the control of the powdery mildew of the apple. The chief disadvantages 

 are that it is somewhat tedious to make as a home preparation and is not 

 well adapted to commercial sale on account of a tendency to deteriorate upon 

 standing for any length of time. 



As prepared according to the originators' formula, each gallon of the 

 paste would contain in the neighborhood of one-tenth of a pound of pre- 

 cipitated sulphur, and the finished spray, one pound of precipitated sulphur 

 to each 100 gallons. 



Proprietary Preparations: Another form of wettable sulphur which 

 might be of interest to viticulturists is a proprietary preparation consisting 

 of between 45 and 50 per cent, of sulphur ground to an impalpable powder in 

 the presence of glue and sufficient water to form a paste. It is readily wet 

 by water, producing a uniform mixture by means of slight agitation so that 

 a very even distribution may be obtained by its use. The finely divided con- 

 dition of the sulphur makes it very active against fungi which are suscept- 

 ible to sulphur. It adheres well to the foliage so that its action continues 

 over a long period of time. According to the reports of some of the State 

 agricultural experiment stations, very favorable results have been shown 

 from its use. 



Another proprietary wettable sulphur is manufactured by grinding to- 

 gether in a paint mill sulphur and diatomaceous earth (kieselguhr) with 

 sufficient water to form a paste. The percentage of sulphur in this prepara- 

 tion varies from 45 to 50 per cent. The preparation is such that it is easily 

 wet by water and it remains well in suspension. There are also very favor- 

 able reports from the use of this material as a fungicide, particularly in the 

 control of powdery mildew of the apple. 



SOLUBLE COMPOUNDS OF SULPHUR. 



An excellent class of soluble sulphur fungicides which has been long in 

 use is the alkali sulphides. Their cost, however, has largely restricted their 

 use to small operations, particularly as a fungicide for the home garden 



