22 the: COLORADO EXPE:rIMENT STATION 
forcefully sprayed upon the exposed roots gave fairly good results, 
but these were not equal in their killing and repelling effects to a 
lo or 15 per cent kerosene emulsion. 
Black Leaf Dip used in the proportion of i gallon in 65 gal¬ 
lons of water gave results similar to the preceding. 
Scalecide used i to 40, i to 50 and i to 60 in water killed the 
lice fairly well, but had very little repelling effect afterwards. 
Soaps used for root treatment were of doubtful benefit. 
Some Wholly Unsuccessful Substances were “Chloroleum,” 
lump lime (10 to 20 pounds to a tree), potash lye, wood ashes, 
salt and flooding with water for several hours. 
ROOT TREATMENT OE NURSERY STOCK 
Apparently none of the inspection laws have prevented, 
though they have greatly lessened, the shipment of trees infested 
with woolly aphis. It is commonly recommended to dip or fumi¬ 
gate such trees to destroy the lice. 
We have found the ordinary dipping process quite ineffectual 
in cases of severe infestations on account of the protection afforded 
by the woolly secretions, but we have had perfect success b}^ untying 
the bundles and forcefully spraying the trees upon roots and tops 
with kerosene emulsion (7 to 10 per cent oil), or one of the tobacco 
or soap preparations used for top treatment. Make the spray 
forceful and drench all ports. It requires but little time or material 
to treat thousands of trees. Where this work is to be done on a 
large scale, a water tight spraying surface or pan could easily be 
arranged with a drainage tank so that the same spray material 
could be used over and over. 
Dipping for 6 seconds in water heated to 140 degrees Far., 
and fumigating for 40 minutes in hydrocyanic acid gas we have 
also found efficient remedies for the destruction of this louse on 
nursery trees. 
CONCLUSIONS AS TO BEST METHODS OE TREATMENT 
Just before the buds open in the spring, spray very thoroughly 
with a 7 per cent kerosene emulsion, Black Leaf dip i pound to 
60 gallons of water (or some other strong tobacco decoction), or 
a good whale-oil soap, i pound to 6 gallons of water. Spray the 
entire trunk and also the ground about the crown of the tree. Im¬ 
mediately after treatment apply a Tanglefoot band over cotton so 
as to prevent the upward migration. If the lice become very num¬ 
erous at any time upon the tops, spray them forcefully with the 7 
per cent emulsion, or Black Leaf, i part in 70 parts of water. 
Root treatments are temporary in their effects. When the 
roots become verv badlv infested, treat as above described with 10 
per cent kerosene emulsion, Black Leaf dip (i to 50), 2 to 3 gal- 
