Feb. 19, 1917 Arsenical Injury through the Bark of Fruit Trees 
309 
INJURY TO CROWNS 
In treating the crowns of trees it was deemed advisable to place the 
chemicals very much as they accumulate as a result of spray mixtures 
running down the trunks. To accomplish this, the earth was removed 
around the crowns to a depth of a few inches, care being taken not to 
injure the bark in the slightest degree, except on certain trees that were 
purposely wounded. The arsenicals were then distributed in these shal¬ 
low trenches against the bark and the earth replaced. Except in apply¬ 
ing the chemicals, no water was added during the course of the experi¬ 
ments, the natural moisture of the soil being depended upon to keep some 
arsenic in solution at least a portion of the time. Fresh applications 
were given in three successive years, the last one being twice the strength 
of the first two. 
The experiments recorded in Table IX show that even small quantities 
of arsenic trisulphid or copper aceto arsenite are capable of causing injury 
to the unwounded crowns. This suggests that in time the injury might 
even girdle the trees. That calcium arsenite would have caused a more 
serious injury in the same length of time seems highly probable, judging 
from a comparison with the other chemicals when applied to branches. 
We must not, however, overlook the possibility that the soil solution 
about the crowns influenced the relative injuriousness of the chemicals. 
TablF IX .—Results of Treating the crowns of apple trees three successive years with different 
chemicals, to determine character of injury 
No. 
Treatment. 
Diameter 
of trunk. 
Wounds at crown. 
Injury, Mar. 25, 1913. 
1 
Arsenic trioxid, Merck; 7 gm. 
Inches. 
A 1 /* 
Un wounded. 
Uninjured. 
2 
July 19,1910, and Aug. 22,1911; 
14 gm. Aug. 8, 1912. 
aH 
Two strips of bark 
Narrow streak runs up 3 feet. 
3 
Arsenic trisulphid, Merck; 15 
aV* 
% by inches 
removed just be¬ 
low ground. 
Un wounded. 
Roots uninjured. 
Several dead spots about 1 inch in 
A 
gm. July 19, 1910, and Aug. 22, 
19x1; 30 gm. Aug. 8, 1912. 
.do. 
a 1 A 
2 
Same as No. 2. 
diameter extend into bark, but 
none reach the cambium. 
Wide streak runs up 3 feet, but does 
not extend down onto roots. 
Several dead spots about 1 inch 
in diameter extend into bark. 
The tissue is very dark and 
friable. Two spots extend 
through bark into wood. 
Apparently uninjured Aug. 8,1912. 
*T 
s 
Lead arsenate, technical, Merck; 
Un wounded. 
6 
60 gm. July 19, 1910, and Aug. 
22, 1911; 120 gm. Aug. 8, 1912. 
4 K 
Water sprouts cut 
Removed before final notes were 
taken. 
Do. 
7 
Copper aceto arsenite, Ans- 
3 K 
from crown. 
Un wounded. 
Several small dead spots on crown. 
8 
bacher; 15 gm. July 19, 1910, 
and Aug. 22,1911; 30 gm. Aug. 
8, 1912. 
3 
Water sprouts cut 
but none reached the cambium. 
Wide dead streak runs up 4 feet. 
9 
Zinc arsenite, ortho, California 
from crown. 
Un wounded. 
This starts from a large dead 
patch on the crown. Roots 
uninjured. 
No injury. 
10 
Spray Co.; 15 gm. July 19, 
1910, and Aug. 22,1911; 30 gm. 
Aug. 8, 1912. 
4 
Same as No. 2__ 
Tree broken down by storm. 
