82 INSECTICIDES AND SPRAYING. 



more delicate caterpillars. Its use is strictly limited to these insects and 

 it cannot be used, for instance, to kill large caterpillars which are best dealt 

 with by means of a stomach poison. 



Kerosene emulsion applied in the ordinary tin hand sprayer, is an 

 excellent remedy for the aphid cb which attack cotton, tuer, beans, pulses 

 and other field crops. In botanic gardens it is useful against all aphis 

 and the majority of the scale insects. In vegetable gardens it can be 

 safely applied against similar pests, and is often usefully applied over 

 the whole of a garden to drive out unwelcome intruders such as crickets, 

 grasshoppers, leaf-eating beetles, plant lice, jumping lice and other 

 insects which are apt to gather in a well watered garden. 



Crude Oil Emulsion. 



The heavier petroleum oils have a more permanent and thorough 

 insecticidal effect, especially where the climate is hot and the lighter oils 

 soon evaporate. The ordinary emulsions cannot l)e made with the crude 

 oil, the best emulsions containing crude oil being made by a special 

 process. Such an emulsion, containing 80 per cent, of crude oil, with 20 

 per cent, of whale oil soap, is prepared and sold, under the name of 

 " Crude Oil Emulsion.^' It was made at the Entomologist^s suggestion, 

 and analysis shows it to be pure, containing the ingredients given above. 



To use the emulsion, it needs to be mixed with cold water in the 

 proportion of \ pint to a kerosene tin of water (-i gallons). This 

 amount measured and placed in a bucket or tin, is readily mixed with 

 water by pumping water on it from a spraying machine or rubbing up 

 the emulsion by hand. It makes a white milky fluid, remaining fit for 

 use for several days, which needs no further preparation before application. 

 This is the usual strength : it may be made twice as strong, and can then 

 still be used safely on all but very delicate plants. 



Like kerosene emulsion, this is simply a useful contact poison. It 

 is harmless to all animals if eaten and has a deadly effect on insects only 

 when they are well wetted with it. It should be applied in the form of 

 fine mist by means of a good spraying machine. For all soft insects 

 such as aphis (Green-fly), mealy bug, thrips, green bug, leaf hoppers, 

 small caterpillars, etc., it is effective. One application kills the greater 

 number and a second application completes the operation. In gardens, on 

 fruit trees, on ornamental plants, on vegetables, it is a useful application 

 for these diseases and has a further use in driving off many other insects, 

 Avhich, though not killed by it, find it objectionable. It has a certain 

 value also in houses, which are infested with obnoxious insects, etc, It 



