6 BULLETIN 899, U. S. DEPAET^IEXT OF AGRICULTURE. 
STOCK MIXTURE. 
The gipsv moth tree-banding material was made in large quan- 
tities as follows: One part by weight of hard coal-tar pitch was 
placed in a large kettle (fig. 1), to which was added one pail by 
weight of coal-tar neutral oil; heat was then applied to the kettle f 
until all of the pitch had melted and thoroughly mixed with the oil : 
the kettle was then removed and two more parts by weight of coal- 
tar neutral oil were added and the contents thoroughly mixed. This 
product, known as pitch neutral-oil mixture, could be poured and 
worked after cooling. 
FORMULA. 
The banding material was mixed as follows : Eighteen pounds of 
the pitch neutral-oil or stock mixture and 70 pounds of the coal-tar 
neutral oil were added to the mixing kettle and the stirrer started 
working. In a few moments 12 pounds of hydrated lime were added 
slowly to the mixture. When the contents had become of a uniform 
consistency 50 pounds of rosin oil were added and allowed to mix 
for a few minutes, or Until the contents began to thicken, after which 
20 pounds of coal-tar neutral oil were added and the contents allowed 
to mix thoroughly. The stirring was then stopped and the material 
poured into containers and allowed to set for two or three days, and 
by the end of this time the material had set into a semisolid state, 
of somewhat softer consistency than cup grease. 
In cold weather this material is slightly stiff, but it can be applied 
easily at a temperature of 35° F. At higher temperatures it works 
very easily. 
Most of the material made so far has been used in Xew England 
and is best suited to a similar climate. If in a much warmer climate 
this product proves to be too soft, it may be made harder by slightly 
increasing the amount of rosin oil and lime. If in a much colder 
climate it proves too hard, it may be made softer by the addition of a 
little more coal-tar neutral oil. 
If an excess of lime is added to bring the material up to the desired 
consistency, the product when finished will have more or less of a dry 
or granular appearance and when placed on the trees will dry out 
more rapidly and become devoid of the oily surface which is most 
desired. 
If the viscosity of the rosin oil varies, it is necessary to alter the 
amount used. Figuring from the viscosity of the rosin oil used in 
this formula, which, as previously stated, is 52 at 100° C, tested with 
a Saybolt universal viscosimeter, a reduction of 4 pounds of the 
rosin oil should be made to every 15 points increase in viscosity. 
When a reduction of the rosin oil is made, it is also necessary to 
make an addition of coal-tar neutral oil. Figuring from the amount 
