38 FRUIT TREES AND THEIR ENEMIES 



5 pints of solar distillate (churning this up with it), 

 or I lb. of water-glass. In the case of sulphur, a 

 certain amount of chemical combination occurs, analo- 

 gous to that occurring in the lime-sulphur-salt washes 

 mentioned below: where solar distillate is used, the 

 effectiveness of the wash on scale is diminished, whilst 

 in the case of water-glass, the results seem to be very 

 uncertain, there being sometimes an increased ad- 

 hesiveness of the wash, sometimes the contrary. 



Lime-sulphur-salt washes are applied in winter to 

 trees, but more as insecticides and fungicides, than as 

 detergent agents. They will be considered under 

 Sulphur Compounds (p. 53). 



12. Lime-salt wash. — This is recommended for the 

 destruction of psylla, and should be applied a few 

 weeks before the buds open. 



(12) Lime . . . . 15 to 20 lbs. 



Salt . . . . 2 „ 3 lbs. 



Water-glass . . . ^ „ i lb. 



Water .... about 8 galls. 



Slake the lime, and mix it with half the water ; in 

 the rest of the water dissolve the salt and the water- 

 glass (sodium silicate) ; mix the two. It is not known 

 yet what the mechanism of the action is in the case 

 of this wash, especially as to the part played by the 

 salt. The amount of this latter has recently been 

 raised from 2 up to 3 lbs., and, if the action depended 

 on it, it might be raised still further, even up to 10 lbs. ; 

 but it is stated that very little advantage has been 

 gained by raising it to 4 lbs. The lime appears to act 



