4 Thk Colorado Experiment Station. 
While the conditions met with in the case of this property 
were not identical with those obtaining in orchard culture, they had 
enough in common with them to convince me that there were but 
two conclusions to draw, either that I was in error in regard to the 
agency of the arsenic in this case, or that there would come a time, 
and that soon, when the arsenic applied would eventually find its 
way into the soil, and prove a source of danger to the trees. I was, at 
that time, going on four years ago, so fully convinced that the arsenic 
would become a source of grave danger, that I ventured to express 
this veiw to the orchardists of the State and cautioned them that 
the probability of injury from this cause was imminent. 
Prof. Gillette, ^vho, as an Entomologist, is interested in the con¬ 
trol of insects injurious to the fruit crops of the State, has repeatedly 
suggested that I should take up this line of investigation, Prof. 
Paddock, also, who, as a Horticulturist, is interested in the dis¬ 
eases of the trees—has made the same suggestion. These state¬ 
ments are not made to devolve any responsibility upon these profes 
sors but to show that this view has not been hidden from the people 
or my colleagues and the presentation of this bulletin is noc 
a hasty resolve or a thing done without a very keen appreciation 
of its importance not only to the orchardists of Colorado but to 
all orchardists. 
I will add before leaving these introductory paragraphs, that 
this work in my Department is directly an outgrowth of my attempts 
to study the alkalies of this State, but I deem it both just to the in¬ 
terests of the State and wise to segregate it, and present it at the 
earliest advisable time, irrespective of the rest of the work. 
It will appear in the proper place how the injuries herein de¬ 
scribed and explained are influenced by the alkali, indeed, the or¬ 
chardists themselves have repeatedly suggested this by such ques¬ 
tions as: Has our strongly alkali water any effect on our spray 
material, specifically upon the lead arsenate? 
While the suggestions of danger were made so long as three 
years ago, no observations of any trouble were officially made 
public until January 1907, when Mr. O. B. Whipple in his report 
as Field Horticulturist of the Western Slope Fruit Investigation, 
calls attention to certain difficulties under the title of Root Rots. 
I give the whole of his report touching upon this subject taken from 
Bulletin 118 of this Station: 
ROOT ROTS. 
“Two apparently distinct forms of root rot are found. One form, 
which is proving the least destructive of the two, seems to show no prefer¬ 
ence for varieties, and confines itself to that part of the tree below the 
ground. The other seems to work exclusively on the Ben Davis and Gano, 
and the trunk as well as the roots are affected. The disease often extends 
upward into the large branches. The first indication of the disease is the ap" 
pearance on the trunk of spots of a chocolate color. When peeled off the 
bark has a peculiar marbled appearance, the diseased portions standing out 
