I9ii.] 



Spraying Experiments. 



883 



" flowers of sulphur" (running the sulphur through a fine 

 sieve in order to break up any lumps) into the slaking lime 

 and add another bucket of hot water. Stir occasionally in 

 order to prevent caking. Cover over the barrel with sacking 

 in order to retain the heat given out by the lime slaking, which 

 will cause the mixture to boil for 10 to 20 minutes, accord- 

 ing to the quality of the lime. During this boiling a small 

 amount of the sulphur goes into solution. As soon as the 

 lime has slaked — that is, as soon as boiling has ceased — 

 add cold water up to the 50-gallon mark, in order to prevent 

 more sulphur going into solution. The mixture should be 

 strained through a sieve of 20 meshes to the inch in order 

 to remove the coarse particles of lime, but all the sulphur 

 should be worked through the strainer. The mixture is 

 then ready for use ; in its application a specially good 

 agitator is required in the tank or barrel of the spraying 

 machine. In this mixture the finely-divided sulphur in 

 mechanical mixture with the lime is depended upon for the 

 fungicidal action rather than the sulphur in solution. Spray- 

 ing experiments lately carried out in the United States have 

 shown that this "self-boiled " lime-sulphur wash acts as a 

 fungicide, but that it is of moderate power only and is not 

 a strong enough fungicide to be recommended for use 

 against severe attacks of apple "scab." It is entirely harm- 

 less to the foliage and fruit of apples; indeed, so safe is it 

 with respect to foliage that it can be used on the tender 

 leaves of the peach. 



In August last a Bulletin was published by the United 

 States Department of Agriculture* in which the results are 

 given of spraying experiments, carried out in 1909, with 

 lime-sulphur washes and also with certain new modifications 

 of them in which either iron sulphate or copper sulphate is 

 added. One of the most promising mixtures is termed the 

 iron-sulphide mixture ; it is prepared as follows : a 50-gallon 

 barrel of the " self-boiled' 5 lime-sulphur mixture is prepared 

 exactly as mentioned above, except that the cold water, 

 when added, must rise not to the 50-gallon mark, but to a 

 40-gallon mark. Then add 10 gallons of water in which 



* U.S. Department of Agriculture, Bureau of Plant Industry, Circular No. 58 

 (August 1, 1 9 10). 



3 Q 2 



