TOBACCO EXTRACT 75 



The manner of making linseed oil emulsion is similar to that of 

 making kerosene emulsion. The material has a special use in fight- 

 ing oyster shell scale. 



To make the stock emulsion take 1 pound of soap, shave up fine, 

 and dissolve in 1 gallon of boiling soft water. When the soap is 

 all dissolved, remove the solution from the fire and add at once 2 

 gallons of raw linseed oil. Churn the mixture violently by pumping 

 it back on itself with a bucket pump. After a few minutes, a yellowish, 

 smooth, creamy emulsion will be formed. No oil should separate out, 

 if the stock is properly prepared. 



To prepare for use, take 1 gallon of the stock and dilute with 

 9 gallons of soft water. This is for use on trees not yet in leaf. 

 For oyster shell scale it is best applied just before the buds swell in the 

 spring. 



Commercial Tobacco Extract 



Highly concentrated extracts of tobacco are now on the market, 

 and constitute a valuable class of contact insecticides. They are 

 dark-colored liquids, and are prepared for use by diluting with water, 

 according to the degree of concentration of the brand purchased and 

 the kind of insect concerned. It is advantageous to add soap to the 

 solution, in order to make it spread more readily and prevent it from 

 collecting in globules. Use 1 pound of soap to 50 gallons of the 

 diluted spray. 



Rather strong dilutions of commercial tobacco extract have been 

 found of possible value as winter sprays to kill the overwintering eggs 

 of certain plant lice on the bark or twigs of dormant trees. 



Weaker dilutions are standard remedies for fighting various soft- 

 bodied sucking insects, such as plant lice, thrips, and the like. These 

 dilutions are applied with perfect safety to trees in leaf. 



Similar dilutions are used as dips for sheep or other domestic ani- 

 mals, to kill mites and lice. 



" Black Leaf 40," containing 40 per cent nicotine sulphate, is used 

 for winter spraying, as noted above, at dilutions ranging from 1 part 

 to 300 of water down to 1 part to 600. For use in summer the dilu- 



