304 
Journal of Agricultural Research 
Vol. VIII, No. 8 
is reported to be easily injured, and the Gano shares somewhat this 
reputation, not so much apparently from actual observation as from 
inference because of the close relationship of the two varieties. Headden 
(5, 7) refers to this Special susceptibility of the Ben Davis and the Gano 
and notes that under some conditions at least these two varieties are most 
frequently victims of crown injury. So far as the spray injury is con¬ 
cerned, this special weakness of the Ben Davis and the Gano may be due 
either to poorer protection of the leaf cuticle (or possibly to some dif¬ 
ference in the stomata) or to a greater susceptibility of the living interior 
portion. Likewise, if the injury described by Headden is caused by 
arsenic which has accumulated about the crown, the more frequent 
injury which he observed in these varieties may have been due to a 
structural difference in the protective outer bark or to a difference in 
the resistance of the inner tissues. 
More than 100 tests were made on wounded and unwounded 
branches for direct comparisons, under practically identical conditions, of 
the relative susceptibility of varieties. The following were included in 
these tests: Alexander, Ben Davis, Gano, Hibernal, Okabena, Wealthy, 
and Yellow Transparent apples; Hyslop and Transcendent crab apples; 
Flemish Beauty pear, and De Soto and Moldarka plums. 
In addition to the tests planned for this specific purpose, many others 
made for different purposes gave additional opportunity for comparisons 
of varietal susceptibility. A fairly representative series is shown in 
Table VI. 
Table VI .—Results of wounding (twig cut off or notch cut to cambium) and treating 
different varieties of apple and plum on June 14, IQl$ y with 10 gm. of Baker's copper 
aceto arsenite , to compare susceptibility of varieties 
No. 
Diameter 
of treated 
branch. 
Variety. 
Extent and character of injury. 
Inch. 
1 
X 
Ben Davis apple. 
Dead above bandage except for narrow strip that runs up 14 inches. 
Streak runs down 2 inches. Several lenticel spots. 
2 
X 
Streak nearly around branch runs up s feet to tip. Narrow streak 
runs down 3 inches. Nearly girdled under bandage. 
Dead above bandage except for narrow strip that runs up 1 foot. 
Streak half around branch runs down 10 inches. 
3 
X 
4 
X 
Gano apple. 
Dead above bandage except for narrow strip that runs up 10 inches. 
Streak runs down 6 inches. 
S 
X 
Streak half around branch runs up 4 feet to tip and down 6 inches. 
Large spot at latent bud. 
6 
X 
Streak half around branch runs up $ feet to tip and down 10 inches 
to main limb and on down this 6 inches. 
7 
X 
Hibernal apple. 
Dead above bandage except for narrow strip that rims up 2 feet. 
Streak runs down 2 inches. 
8 
X 
Dead above bandage. Streak half around runs down 6 inches to 
main limb. 
9 
X 
Wide streak runs up 22 inches. No injury below bandage. Several 
lenticel spots. 
10 
X 
Okabena apple. 
Streak two-thirds around branch runs up 3 feet to tip. Wide streak 
runs down 6 inches. Three lenticel spots. 
IX 
X 
Dead above bandage except for narrow strip that runs up 16 inches. 
Wide streak runs down 2 feet to main limb. Several lenticel spots. 
13 
X 
.do. 
Streak two-thirds around branch runs up 4 feet to tip. No injury 
below bandage. Several lenticel spots. 
13 
X 
Oldenburg apple. 
Streak half around limb runs up 9 inches to side branch and out this 
X4 inches. Wide streak runs down 7 inches. Several lenticel 
spots. 
*4 
X 
Dead above bandage except for narrow strip that runs up 15 inches. 
Streak half around runs down 7 inches. 
