10 
COLORADO EXPERIMENT STATION 
probably would not live through another year. None of the weaker pre¬ 
parations seem to have done any injury to the trees. 
CONCLUSIONS AS TO BKST METHODS OF TRFATMFNT 
Just before the buds open in the spring, spray very thoroughly with a 
7% kerosene emulsion, a i to 6o Black Leaf Dip (or some other strong 
tobacco decoction), or a good whale-oil soap, i-lb to 6 gallons of water. 
Spray the entire trunk and also the ground about the crown of the tree 
at the same time. Immediately after treatment apply a Tanglefoot band 
over cotton so as to prevent the upward migration. If the lice become very 
numerous at any time upon the tops, spray them forcefully with the 7% 
emulsion, or Black Leaf, i part in 70 parts of water. 
Root treatments are temporary in their effects. When the roots be¬ 
come very badly infested, treat as above described with 10% kerosene emul¬ 
sion, Black Leaf Dip (i to 50), 2 to 3 gallons to a tree, or if the soil is 
quite open and porous, carbon bisulfid.* 
CARBON BISULFID 
This insecticide has often been reported successful against this insect. 
A splendid opportunity was afforded to observe its results in the 20 
acre orchard of Mr. F. D. Barney, where about 200 pounds of the liquid was 
used on 12-year-old apple trees. The treatment was begun on April ii, 
1907, and was continued several weeks from this date. 
A shovel was thrust deeply into the ground about 18 inches to two 
feet from the base of the tree with the blade broadcast to the tree. The 
handle was then tipped forward and the carbon bisulfid poured into the 
bottom and at the center of the opening at the back of the shovel. The 
shovel was then withdrawn and the earth packed upon the spot treated. 
The liquid was not poured directly upon the roots. From three to six holes 
were treated in this way about each tree and about three ounces of the 
liquid used. At this rate the cost of the material did not amount to as 
much as three cents per tree. 
TOBACCO DUST AND STEMS 
Dry tobacco in the form of tobacco dust or tobacco stems or even the 
whole leaf tobacco when used freely about the trees has not given very 
satisfactory results. Apparently these substances are of no use unless the 
tobacco is thoroughly wet, as soon as it has been placed about the roots, 
so that the juices will penetrate the soil and kill the lice. In a few in¬ 
stances orchardists have reported very satisfactory results but in nearly 
all cases they have reported failure. We believe if tobacco is used 
at all against this insect upon the roots of trees the best method is to apply 
it in the form of a strong decoction. 
Prepare as for a top spray and use two or three gallons about each 
tree as in case of kerosene emulsion as described above. The tobacco does 
not have as lasting an effect apparently as does the emulsion. 
*Carbon bisulfid may be procured in quantity from Edward R. Taylor, 
Penn Yan, New York. 
