184 Indian Economic Entomology. [Vol. L 



Syringing as a prophylactic would be of little use in the rains, as in 

 a day of heavy rain the substance used would be washed away. Spray- 

 ing infected tips when the attacks first appear with kerosine emulsion as 

 an insecticide appeai-s to promise good results. It has been of practical 

 value in the case of coccid pests on coffee, and is very simply made. The 

 proper course suggested by the life-history of the insects is to search for 

 the eggs, and to spray those places where they occur, for, as a rule, in 

 the earliest stages, the larvse are found only where the eggs have been 

 deposited. A useful formula for kerosine emulsion prescribed in America, 

 to be varied according to circumstances and experience, is that given in 

 No. £ of " Notes on Economic Entomology," and which for reference is re- 

 produced here : — 



" An emulsion resembling butter can be produced in a few minutes by churning 

 with a force-pump two parts of kerosine and one part of sour-milk, or soap solution, 

 in a pail ; emulsions made with soap solutions being generally found to be the more 

 effective. The liquids should be at about blood heat. This emulsion may be diluted 

 with from nine to fifty parts of water, which should be thoroughly mixed with one 

 part of the emulsion. 



" The strength of this dilution must vary according to the nature of the insect to be 

 dealt with, as well as to the nature of the plant ; but finely sprayed in twelve parts of 

 the water to one of the emulsion, it will kill most insects without injury to the plant." 



It should be applied through a spray nozzle— 



" The nozzle which best combines the necessary qualities is undoubtedly the eddy 

 or cyclone nozzle, consisting of a small circular chamber with two flat sides, one of 

 them screwed on, so as to be readily removed. Its principal feature consists in the 

 inlet, through which the liquid is forced, being bored tangentially through its wall, so 

 as to cause a rapid whirling or centrifugal motion of the liquid, which issues in a 

 funnel-shaped spray through the central outlet in the adjustable cap. The breadth or 

 height, fineness or coarseness, of the spray depends on certain details in the propor- 

 tion of the parts, and specially in the central outlet. 



" To drive the liquid through the nozzle some kind of force-pump is required, and 

 a great number have at different times been experimented with, some of them being of 

 a most complicated nature. It is perhaps not of any very great consequence which 

 particular form is adopted for use in India; but the aquapult force-pump, which has 

 been arranged to be worked entirely by one man, who also distributes the spray, seema 

 to be about the best suited for general use in a country where economy in labour is 

 generally not so great an object as economy in the cost of apparatus." 



Amongst the many remedies proposed, cutting down the forest and 

 grass jungle adjoining plantations has found some favour. A writer in 

 the Calcutta Journal already quoted suggests that toon trees may harbour 

 the insect (November 1885), another that spear grass and other similar 

 growths furnish the shelter. There is no doubt that in this country 

 grass harbours vast numbers of Capsida, and it is quite possible that the 

 original food-plant of the insect may be discovered and eradicated. It 

 is, however, for the planters themselves to discover this, and there can 

 be no harm in removing and burning during the cold weather grass 

 jungle in the neighbourhood of plantations. Some support is given to 



