FUNGICIDES AND THEIR APPLICATION 95 



use as a substitute for Bordeaux mixture where the effect ofthe 

 latter in protecting scale-insects is a disadvantage (often the case 

 with citrus trees), and in concentrated form it has a powerful 

 and sometimes very valuable elfect in keeping the bark of trees 

 clear of moss and other surface growths. 



Stock solution is prepared according to the following formula : 

 Best stone lime (about 95 per cent.) 50 lb. 

 Flowers or flour of sulphur . . 100 lb. 

 Water 40 gall. 



An iron vessel must be used for the boiling, and must be of 

 sufficient size to contain the large amount of froth formed in 

 the early stages. About half the water is first made hot, the 

 lime added, then the sulphur, with vigorous stirring until both 

 are well mixed, and then the rest of the water. The fire should 

 not be allowed to get fierce, and splashes on hands or clothing 

 must be avoided. Either about 3 gallons of extra water should 

 be added at the beginning, or the water lost in boiling should be 

 replaced from time to time, preferably by hot water, so that the 

 level when boiling is complete is near 42 gallons hot or 40 cold, 

 as shown by a measuring stick or mark previously prepared. 

 The volume at boiling point may be taken as 1.05 of the volume 

 cold. Actual boiling should continue for 45 minutes ; long 

 boiling reduces the amount of sulphur in solution. A steam 

 jet may be used for boiling, in which case no extra water is 

 required. The sediment should be strained out before storage, 

 using 30-50 mesh brass or tinned iron (not copper) gauze. 



If the available boiler is small, half the water may be kept 

 back until boiling is complete, but the resulting solution is not 

 quite so good. If preferred the lime and sulphur may be placed 

 in the boiler and well mixed with half the water before heating, 

 and the remaining half added a little later. 



The stock solution will keep well if not exposed to air. It 

 may be stored, after being well mixed to secure even distribution 

 of the sludge, in full stone jars or bottles kept closed down, or in 

 barrels if covered with a layer of mineral oil (kerosene or pre- 

 ferably lubricating oil). 



For use as a spray the solution thus prepared, after straining, 

 needs dilution at the rate of about 20 gallons of water to i gallon 

 for resistant foliage, 30-40 to i for more tender leaves. To 

 avoid the danger of scorching foliage, the strength may be 

 controlled by means of a hydrometer, the diluted spray being 

 used at strengths of approximately i|° Baume for resistant 

 and 1° or 0.7° Baume for more tender foliage. The correct 

 strength for the work in hand must be determined by experiment. 



The new Baume scale is used in the following dilution table, 

 but hydrometers graduated on the old scale may be used viithout 

 affecting the results to a significant extent. 



