ORCHARD PLANT LICE AND THEIR REMEDIES 
9 
TREATMENT BEEOW GROUND 
The treatment below ground is all aimed at the lice that are within 
three feet of the crown of the tree and within one foot of the surface. It 
should also be remembered that the same substances that will kill the lice 
above ground will also kill them below ground if they can only be put in 
contact with the lice, and then the orchardist should be cautious not to ac¬ 
cumulate in the soil about the crowns of his trees substances that are likely 
either presently or after years of repetition, to do his trees an injury. 
EXPERIMENTS IN GRAND VAEEEY 
A rather extensive series of experiments for the purpose of testing sub¬ 
stances that seemed to offer some promise of good results were carried 
through in irrigated orchards of the Grand Valley in Colorado, a summary 
of which is given below. 
THE APPLICATIONS AND THEIR RESULTS 
The experiments were begun in the fall of 1906 and the winter following 
The materials used upon the roots were Kerosene Emulsion, Scalecide, 
Chloroleum, Black Leaf Dip, tobacco dust, tobacco dust decoction, tobacco 
stems, tobacco stem decoction, quick lime, lime-sulfur mixture, Rex lime- 
sulfur, whale-oil soap, and carbon bisulfid. 
Before making the applications the earth was removed over the main 
roots to a depth of about 6 inches, and for a distance of about 2 feet upon 
all sides, of each tree. One man on an average would expose the roots of 
about 100 trees a day. Into these dirt basins which varied some in depth 
and diameter with the size and depth of the roots of the trees, the liquids 
were forcefully sprayed so as to well drench the exposed portions. And 
when the liquid had nearly or quite soaked into the ground the basin was 
filled again and the earth banked well about the trees. In hard compact 
soils it is best to irrigate a few days prior to making the treatment so as to 
loosen the soil, and lessen the labor of excavating about the trees. 
Summing up the results to September, 1907, it may be said, that 
practically all strengths of kerosene emulsion (3% to 50%), killed the lice 
well when the roots had been well treated. Where less than 6% of oil was 
used, the odor of kerosene soon disappeared and reinfestation soon took 
place by the lice that migrated downward from the top. Where, 7, 10, and 
15% of oil was used the effect was still more lasting; and the 20, 33 and 
50% treatments gave practically perfect freedom from lice about the crown 
and roots throughout the season. 
A later examination was made by Mr. George P. Weldon, 1908. Mr. 
Weldon found the woolly aphis about equally abundant upon the treated and 
untreated trees in all of the blocks. Even those that were treated with 
50% kerosene emulsion were badly infested upon the roots at the time that 
he made his examination. So we have to conclude that an}^^ treatment for 
the destruction of the woolly aphis upon the roots is only of temporary 
value. But the stronger preparations do repel the lice for a short period of 
time, perhaps two or three months. Mr. Weldon also found that where the 
50% emulsion was used the trees appeared to be seriously affected and 
