Hke Tea insects of India. 63 



On aceount of their poisonous nature neither Paris green nor London 

 purple should be used under any circumstance whatever upon tea bushes 

 where plucking- is going on. And no leaves or buds^ which were in 

 existence at the time that the spraying was done, should on any account 

 be made into tea. Provided, however, that the bushes are well washed 

 by rain subsequent to the application, and that sufficient time is 

 allowed to elapse before plucking for an entirely new flush to appearj 

 it would seem to be impossible for the tea to be affected in any way. 

 As an additional precaution, however, it might be as well in the first 

 instance to have the leaf tested chemically for the poison, though the fact 

 that the closest investigation in the United States has failed to de- 

 tect its presence in fruit picked from trees the foliage of which, only a 

 few months previously, has been liberally treated with the wash, would 

 seem to be sufficient indication that there is no possibility of danger upon 

 this score. 



The usual system for applying both Paris green and London purple \s 

 to simply mix the powder^ with water and to spray the mixture, which is 

 purely a mechanical one, over the plants. The powder, however, has a 

 great tendency to settle to the bottom of the receptacle, and thus render 

 the top too weak and the bottom too strong. To obviate this difficulty 

 the mixture should be constantly stirred, and when empty the receptacle 

 should invariably be rinsed out with water as a preliminary to refilling, 

 for this prevents the accumulation of the poison at the bottom. A little 

 flour is sometimes added to the mixture both to render it more stable, 

 and also to help it to adhere to the leaves; this, however, is by no 

 means essential, provided the other precautions are taken. 



The precise amount of poison to be mixed with the water varies 

 according to the nature of the insect and the resisting power of the 

 foliage. When too strong the leaves are burnt, and when too weak the 

 insect survives. Between these two extremes, however, there is usually 

 })leiity of room for the production of a satisfactory mixture. 



For use against the web worm in the United States the following 

 proportions have been recommended : Forty gallons of water, one quarter 

 to three quarters of a pound of London purple and three quarts of flour, 

 the solid ingredients to be mixed with the water by washing them 

 through a strainer. 



One pound of Paris green similarly mixed with from forty to one 

 hundred gallons of water has been recommended for general use in 

 America. In England for use upon young foliage, the proportions re- 

 commended have been one ounce of Paris green to ten gallons of water in 



r J Paris green is also luanufacturecl in the form of paste to be similarly used.^ The 

 paste has the gresvt recoiiiTOendation of not being liable to get blown about by tlie wind in 

 TPixing, 



