Oct. 13, 1923 
A New Tumor of the Apricot 
53 
which was soon isolated in pure culture; in three weeks’ time it formed 
spores. It was identified as belonging to the genus Monochaetia Sacc. 
Inoculations were made with pure cultures into 2-year-old nursery trees of 
several varieties of apricot and cherry. These plants were growing in 
pots, and, with the exception of two which were placed in the green¬ 
house, were standing in the open. In all the inoculation experiments 
the surface of the region to be inoculated was carefully disinfected with 
corrosive sublimate (1:1000) for from 10 to 20 minutes, and the disin¬ 
fectant was then washed off with sterile water. A slanting cut was made 
with a flamed knife, and pieces of fungous mycelium with spores were in¬ 
serted. About one control, consisting of a cut which was not inoculated, 
was allowed for every three inoculations. The treated area was then 
wrapped with waxed paper as a precaution against external infection 
and drying out. The results of the inoculations may be seen from the 
following table: 
Trees inoculated. 
Date of inoculation. 
Number 
of inocu¬ 
lations. 
Number 
of 
controls. 
Results of inocu¬ 
lations. 
Controls. 
Moorpark apricot.. 
Mar. 16 to 18... 
9 
3 
8 positive; 
Healed over. 
1 doubt- 
ful. 
Do.°. 
.do. 
0 
2 
0 positive.... 
Do. 
Royal apricot. 
Feb. 16 to 26.... 
4 
O 
I 
4 positive.... 
Do. 
Early Newcastle 
3 
1 
3 positive.... 
Do. 
apricot. 
Royal Ann cherry. 
Feb. 14 to 16.... 
4 
2 
.do. 
Do. 
° This tree was in a very poor condition, which may account for the negative result obtained from the 
inoculations. 
The positive results consisted in the formation in the course of two 
or three weeks of small, heavily gumming cankers, which became sta¬ 
tionary at the end of several months and healed over the following 
year. No gall growth was formed on any of the inoculated young 
trees.® 
On February 25, 1916, 12 inoculations were made in four branches 
of an old apricot tree of an unidentified variety, probably a seedling. 
Branches about 4 to 6 years old were chosen for the purpose. In this 
case the inoculations were made, not into slanting cuts, but into notches 
formed by making two deep parallel cuts across the branch and remov¬ 
ing the intervening bit of bark and wood tissue. This later afforded 
a good opportunity for comparing the normal callousing of the wounds 
in the controls with the gall growths which formed in the inoculations 
and for differentiating them. In the course of about three weeks small 
cankers formed about all the inoculations, accompanied by more or less 
abundant gumming. The lesions continued in a state of constant 
gumming for nearly six weeks without showing any other changes. 
About the first week in April, however, when the growing season had 
well started, a swelling became noticeable around the gumming lesions, 
accompanied by a longitudinal cracking of the bark. It soon became 
evident that new tissue was being formed there. The throwing out of 
• Similar results were obtained by Miss E. H. Phillips on Royal apricot from inoculations made in March, 
19x6. 
