518 Appendix. 



Preparation. 



Boil the quassia chips in water for a couple of hours, then dissolve the 

 soap in warm water, if possible, and mix the strained-off quassia extract 

 with the soap. 



Another method of preparation consists of boiling the quassia with 

 half the soap and half the water, strain off the liquid and boil the residue 

 for one hour with the rest of the soap and water, and mix the two 

 decoctions and make up to 10 gallons of water. 



Uses. 

 For the destruction of all aphides and psylla. 



Time of Application. 



As soon as the aphides hatch from their eggs, or appear on the plants, 

 if migrants ; for psylla, when in the trusses of blossoms or when they are 

 hatching. 



VEGETAL WASHES. 



These are particularly useful, on account of their being quite innocuous 

 to the plants and at the same time have very powerful insecticidal 

 properties. 



There are three used, namely : — 



(1) Tobacco Wash. 



(2) Hellebore Wash. 



(3) Pyrethrum. 



All three of these are also used as dry powders for dusting, but applied 

 in liquid form they are found more successful. Tobacco and pyrethrum 

 are also used as fumigants. 



Tobacco Wash. 



Preparation. 

 Infuse the tobacco powder or leaf in water for about six hours, then 

 strain off and press the tobacco and infuse again. Add the tobacco 

 extract to the dissolved soft soap and water. 



