256 



Mr. H. G. Hubbard, and usually recommended by Prof. Riley 

 as follows : — 



"Kerosine Oil ... ... 2 gallons = 67 per cent. 



Common Soap, or Whale-Oil Soap i pound) _ oo , . i.. 



Water ... ... ... 1 gallon/ — * ' P 



Dissoh'e the soap in the water by heating, and add the solution, 

 boiling hot, to the kerosine and churn the mixture by means of a 

 force-pump and spray-nozzle for five minutes. The emulsion, if 

 perfect, forms a ci-eam which thickens on cooling and should 

 adhere without oiliness to the surface of glass. Dilute, before 

 using, one part of the emulsion with nine parts of cold water. 

 The above formula makes 3 gallons of emulsion, and when diluted 

 gives 30 gallons of wash." 



This is applied by means of a pump and nozzle, and the more 

 finely it can be sprayed on the better. Many different modifica- 

 tions of both pump and nozzle have l^een brought into use in the 

 United States, and are discussed by Prof. Ptiley in Dr. Packard's 

 work on Forest Insects (5th Report U. S. Ent. Commission). 

 The ))est known nozzle is that called the Riley or C3'clone nozzle ; 

 and a modification of it, the Vermorel nozzle, has proved success- 

 ful in France. The Nixon or Climax nozzle is also said to be 

 very satisfactory, especially where considerable force is required. 



Resin washes have been used extensively in California against 

 scale-insects, as also various compounds of kerosine with reisn, 

 &c. In adopting these methods for Jamaica, it must always be 

 remembered, that some remedies which may serve excellently in 

 temperate regions, at times when there is no fresh foliage on the 

 trees or they are bare of leaves, might be extremel}'' injurious in 

 a tropical country, where there is always a quantity of foliage 

 liable to injury. It appears to be the custom in Colifoi'nia to 

 apply the resin washes principally in the late summer and 

 autumn ; and no doubt we might do well in Jamaica, by selecting 

 that time for spraying when the affected tree has fruited, and is 

 undergoing a period of more or less rest. * The extent of this 

 resting period in the tropics varies very much among the different 

 species ; thus, the Poinciana regia, as every one in Kingston has 

 the opportunity to observe, has a very distinct interval between 

 the successive floweinng periods, while the orange of course 

 exhibits flowers and fruit at once. There can be little doubt I 

 suppose that every species of tree has some period when a wash 



* It is to be observed that the condition of the scale-insects, whether 

 old or young, &c., has to be also considered ; this is a matter rather to be 

 dealt with under the head of the several species. Sometimes the empty 

 sacs make a considerable show after the insects have left them, but ot 

 course there would be no use in spraying these ! 



