26 The: Colorado Expe:riment Station. 
tially a malate of lime which would require 25.7 per cent of this 
substance, calcic oxid. These trees do not present the symptoms 
described for the arsenical poisoning, though arsenic is very abund¬ 
ant. The question is—Are these trees suffering from systemic 
arsenical poisoning, lime poisoning or both ? These soils are marly 
or have a subsoil of this material and the presence of 25 per cent 
of lime in the dried sap seems to me to be a very suggestive fact. 
I have no remedy to suggest for either condition. Preventive 
measures are so far as I can see, our only recourse. Those which 
suggest themselves to me are: to remove the arsenic laden soil 
from about the crown of the tree and replace it with fresh soil; to 
use the standard brands of lead arsenate in preference to the arsenite 
of lime or white arsenic, sal soda and lime; to use as little lead ar¬ 
senate as possible. I have been told that good results have been ob¬ 
tained by using 21-2 and even 2 pounds of pasty lead arsenate to 
100 gallons of water, but the spraying must be done thoroughly. 
Spray no oftener than is absolutely necessary. If I am not mistaken 
Prof. Gillette has found that 95 per cent of the effect of the whole 
season’s spraying was obtained by the first spraying when thorough¬ 
ly well done. Some device should be used to prevent the spray ma¬ 
terial from running down the trunk and collecting at its base or it 
would be still better to make provision for gathering the whole 
of the drip. Water rich in alkalies should not be allowed to flow 
close enough to the tree to permit of the deposition of the alkalies 
in the soil about the trunk of the tree. Concentrated lye, if used 
to kill the woolly aphis, should not be applied to the soil at the 
crown of the tree or permitted to flow down and collect there. 
SUMMARV 
First: There is a large number of fruit trees in the State 
which are suffering from an affection of the trunk and root. 
Second: This trouble begins, in by far the greater number of 
cases, at the crown of the tree and subsequently involves both 
trunk and roots. 
Third: The first marked symptom is an early ripening of the 
foilage usually followed by death about midsummer of the ensuing 
year. 
Fourth: The crown of the tree is found to be girdled, the bark 
on portions of the trunk dead and sunken and most of the roots 
dead, their bark destroyed and the woody tissue discolored, usually 
a light shade of brown and sometimes exteriorly blackened. 
Fifth. Soluble arsenical compounds will effect the destruction 
of the bark, the staining of the wood, the production of the so- 
called “black heart” and the speedy death of the tree. 
Sixth: Arsenical sprays have been used in these orchards for 
a number of years. 
