IIOSIN WASHES. 83 



acts simply as a lii^'h class insocticidal soap, witli a loss objectionable 

 smell than carbolic preparations. In this way it is deadly to fleas for 

 instance. 



It has a further value on domestic animals : kerosene is an excellent 

 application for the skin and there is "no better way of applying- it than 

 in the form of soapy emulsion. For ticks, fleas, and other insects 

 infesting' cattle, horses, dogs, elephants, sheep, etc., this emulsion should 

 be used, at the same time destroying the insects and improving the skin. 



It is obtainable in five-gallon drums from chemists at Rs. 8-14-0 per 

 drum. 



Rosin Washes. 



Rosin has for many years formed the principal ingredient of many 

 excellent washes for sucking insects. When boiled in water with a 

 suitable chemical, rosin dissolves, forming a clear brown wash which can 

 bo safely applied to plants at a strength sufficient to kill many insects. 

 It is used in this way against many of the most resistant scale insects. 

 A rosin wash of this kind on drying forms a varnish, which asphyxiates 

 some insects by closing the stigmata on the sides of the body through 

 which they obtain air. It needs to be applied as a fine mist, by means 

 of a good spraying machine, and then has a considerable wetting power, 

 covering the insects with a film of liquid which on drying kills them. 



There are a variety of formulae for preparing this wash. Two may 

 be taken as being the simplest and best, both having been tested in India 

 and found fully effective. (See Appendix A, page 284.) These washes 

 are similar in effect and use. The second contains fish oil soap as well as 

 rosin and is a more powerful wash in consequence. As caustic soda and 

 fish oil are less easy to obtain than washing soda, the first wash should 

 generally be used. Only when large quantities are to be prepared is it 

 advisable to use the second wash. The rosin used must be the clear brown 

 fir tree rosin imported from Europe. This rosin may also be obtained 

 from the Forest Department at Dehra Dun and Naini Tal. 



The washes cost about Rs. 3 per 100 gallons, or Rs. 4 per 100 gallons 

 on estates far from the coast and a railway station. 



These washes are for use against scale insects such as brown bug, 

 green bug, black bug, etc., also against green fly (aphis) and similar 

 small sucking insects. They have not the wetting power of kerosene 

 emulsion and so are less effective against mealy bug or other mealy 

 insects. They are excellent contact poisons, useful against a variety of 

 pests. Diluted wash (1 lb. of rosin to 10 gallons of water) is also 

 •valuable with lead arseniate, used as a stomach poison, since it protects the 



