SPRAYING AGAINST GREEN BUG 43 



less by the sooty mould on the upper surfaces of the 

 leaves. If any plant has this appearance, it is almost 

 certain that the plant or the shade tree above is inf3cted 

 with scale insects of some sort. But this symptom is not 

 found until the scales on the coffee or on the^ shade tree 

 are fairly numerous. If this stage has not been reached, 

 one has to look for ants constantly moving about in large 

 numbers on the plants. If plant's have a large number of 

 ants on them there is almost certain to be some insect 

 which yields honey dew. It may be a species of dark 

 plant louse sometimes found crowded on the very tender 

 twigs and leaves, but this insect is rare on coffee. The 

 more likely insect is a scale, and, if it is found, the 

 species can be determined with the help of the descrip- 

 tion given in the earlier part of the bulletin and by a 

 comparison with the coloured figures given in the frontis- 

 piece. „ 



Spraying to Combat Green Bug. 



When the infested patches are located, they should 

 be marked conspicuously by long poles struck into the 

 ground with white or red rags at the top. When this is 

 not done there is often difficult}^ in finding the patches 

 again. The plants should then be sprayed. In spraying, 

 care should be taken that all the infested plants and those 

 round them receive 'the solution in all parts, so that no 

 bug escapes thorough wetting. 



The insecticide at first used was a resin wash with 

 soap. This was commonly prepared as follows: — 



One pound of soda was dissolved in about one 

 gallon of water in a 4-gallon kerosene tin. A pound of 

 powdered resin was stirred in and boiled until the resin 

 was dissolved and the mixture assumed the colour of 

 coffee decoction. One pound of ordinary bar soap was 

 added in shavings until it was also dissolved. Water was 

 then added to fill the tin and the solution was allowed 

 to cool, when it was ready for use. 



The solution as thus prepared was by no means 

 cheap. The price of one cwt. of resin was, at the time, 

 (1912-1913) Rs. 14-8-0, one cwt. of soda cost Rs. 7 and 

 one cwt. of Gossage's bar soap, about Rs. 20. Therefore 

 the cost of the materials alone for 100 gallons of the mix- 

 lure was roughly Rs. 9. The preparation of the mixture 



