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Treatment. 



As plant lice suck plant juices, no poison like Paris green 

 or arsenate of lead is of the slightest value, and something 

 that will destroy these insects by touching them is necessary. 

 Such a substance is kerosene emulsion, which kills by cov- 

 ering the body of the insect with a thin film of oil, and suffo- 

 cating it. In order to obtain good results with this material, 

 however, it is necessary to touch every individual, which it 

 is exceedingly difficult to do, even when the insects are not 

 protected by the curling of the leaves, because of their small 

 size. To treat for plant lice successfully, therefore, spraying 

 should be begun as soon as the lice appear; and, as most of 

 them are on the underside of the leaves, the spray should be 

 directed upward, to reach as many as possible. 



Of the many ways of making kerosene emulsion, the fol- 

 lowing is probably the best : — 



% pound of hard soap, shaved fine. 



1 gallon soft water. 



2 gallons kerosene. 



Dissolve the soap in the water, which should be boiling; remove 

 from the fire and pour it into the kerosene while hot. Churn this 

 with a spray pump till it changes to a creamy, then to a soft, butter- 

 like mass. Keep this as a stock, using one part in nine of water. 

 If the water is hard, add a little soda or borax before churning. 



In some cases a strong stream of cold water thrown from 

 a hose upon an infested plant is quite effective, knocking off 

 and killing the lice ; and sometimes spraying with very strong 

 soap suds is also successful. 



In the case of the pea-vine louse it is difficult to reach 

 the insects by spraying, and here the best practice is to fol- 

 low along the rows on a hot day with a branch from an 

 evergreen tree, and switch the lice off the vines onto the 

 ground, which can be easily and rapidly done. A cultivator 

 should then follow along the rows, and, by loosening the 

 hot dry soil in this way the lice will be dried up and die 

 before they can return to the plants from which they were 

 switched off. 



