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- 
