46 THE COLORADO EXPERIMENT STATION 
PRECAUTIONS 
When preparing and using kerosene emulsion remember: 
To use soft clean water is possible. 
To have the mixture as hot as possible for emulsifying. 
To see that the oil, or mixture of oil and soapy water does not 
boil over into the fire. 
To see that the oil does not separate to form a layer of kero¬ 
sene on top. If this condition exists, the last of the barrel or tank 
will be almost sure to burn the foliage. 
To remember that the strength of the emulsion depends upon 
the percentage of oil it contains. 
To use kerosene emulsion alone, do not try to combine it with 
arsenical sprays. 
To apply forcefully and thoroughly so as to wet the insects as 
it only kills by coming in actual contact with their bodies. 
TOBACCO DECOCTION 
Tobacco stems or tobacco dust two pounds. 
Water four gallons. 
Put the tobacco in the water which may be either cold or hot. 
Place over the fire and when the water has reached the boiling 
point, remove some of the fire and allow the water to simmer, but 
not boil,* for fully one hour, when the liquid is ready to be drained 
off and applied. 
If the whole leaf tobacco is used, prepare as above using one 
pound of tobacco to each four gallons of water. 
No lime or other akaline substances should be added to the 
tobacco while cooking. Apply at once, or within a few days after 
making. 
BLACK leap 
There is nothing to do in the preparation of Black 
Leaf except to thoroughly stir the contents of the can before pour¬ 
ing out any quantity for dilution. In most cases one gallon of the 
Black Leaf will be found sufficient for each seventy gallons of 
water. If in the treatment of any louse this does not seem sufficient 
it may be used in the proportion of one gallon to sixty or sixty-five 
gallons of water. In fact, we have usually succeeded in killing 
plant lice with this preparation used in the proportion of one gal¬ 
lon to each one hundred gallons of water. Thoroughness of appli¬ 
cation is of as much importance as the strength of the material used. 
If this substance is not obtainable in your home town it may be 
procured from the Watkins Merchandise Co., Denver, or from The 
Kentucky Tobacco Product Co., Louisville, Kentucky. 
»Dr. W. P. Headden, Station chemist, says that nicotine will be par¬ 
tially driven off by boiling-. A distillaite he prepared killed lice when diluted 
to 1-8 strength. 
