Feb. i 9 ,1917 Arsenical Injury through the Bark of Fruit Trees 
305 
Table VI .—Results of wounding (twig cut off or notch cut to cambium) and treating 
different varieties of apple and plum on June 14, IQ15, with 10 gm. of Baker's copper 
aceto arsenite , to compare susceptibility of varieties —Continued 
No. 
Diameter 
of treated 
branch. 
Variety. 
Extent and character of injury. 
15 
H 
Oldenburg apple. 
Dead above bandage except for narrow strip that runs up 5 inches. 
Two streaks run down 5 inches. 
Streak half around branch runs up 3 feet to tip and down 4 inches. 
Several lenticel spots. 
16 
H 
Wealthy apple. 
17 
H 
.do. 
Do. 
18 
H 
Streak half around branch runs up 3A feet to tip. Narrow streak 
runs down 3 inches. Several lenticel spots. 
19 
H 
Yellow Transparent 
apple. 
Streak half around branch runs up 5 feet to tip. Narrow streak 
runs down 5 inches. One lenticel spot. 
20 
H 
Streak half around branch runs up 2 feet. Wide streak runs down 
7 inches. Several lenticel spots. 
21 
H 
Wide streak runs up s l A feet. Narrow streak runs down 5 inches. 
Several lenticel spots. 
22 
A 
Hyslop crab. 
Dead above bandage except for narrow strip that runs up 6 inches. 
Wide streak runs down 8 inches. 
23 
H 
Streak two-thirds around branch runs up 2 A feet to tip. Wide 
streak runs down 5 inches. Many lenticel spots. 
24 
H 
Streak half around branch runs up 18 inches and down 3 feet. Sev¬ 
eral lenticel spots. 
«S 
A 
Transcendent crab... 
Dead above bandage. Wide streak runs down 8 inches. 
26 
A 
Streak three-fourths around branch runs up 4 feet to tip. Streak 
runs down 3 inches. 
27 
A 
Streak half around branch runs up 5 feet to tip. No injury below 
bandage. 
28 
A 
DeSoto plum. 
Streak half around branch runs up 3 feet to tip. Streak runs down 
8 inches. 
29 
H 
.do. 
Streak half around branch runs ups A feet to tip and down 2 inches. 
30 
A 
Streak half around branch runs up 3 A feet to tip. Wide streak runs 
down 5 inches to main limb ana on down this 1 foot. 
Throughout our work we find little evidence of any important difference 
in the susceptibility of varieties of apple to arsenical injury when the 
chemical is admitted through wounds. If conclusions were drawn from 
this table alone, it might be inferred that the Wealthy is somewhat more 
resistant than the others; but this is not borne out by other tests. It may 
be said further of the tests reported in this table that the triplicates check 
with each other fully as well as the majority made in this investigation. 
The few tests made of pear and plum lead to the belief that they are not 
very different from apple under these conditions—namely, when the 
arsenical is applied to wounded branches % to ^ inch in diameter. 
In the tests on unwounded branches to compare the susceptibility of 
varieties, 10 gm. of copper aceto arsenite were used in most cases. 
This produced lenticel spots but no streaking on every treated branch of 
every variety of apple tested. The number and size of these spots 
seemed to vary about as much between the duplicates or triplicates on 
the same variety as between varieties, and we got no evidence of special 
susceptibility or resistance in any variety of apple. In the Flemish 
Beauty pear there was a much greater tendency for the lenticel spots to 
enlarge and anastomose, and in the Moldarka plum there was a discolo¬ 
ration of all the outer bark which rarely reached the cambium. Pos¬ 
sibly, if the bandages had been kept on for a very long time, a gradual 
extension of the injury might have taken place in which some varietal 
difference would have been apparent. 
