SOURCES OF APPLE BITTER-ROT INFECTIONS. 1l 
2-to 5 cm. and widths varying from 1 to 1.5 cm. The growth from 
the inoculation in the 1-year branch was even greater, the dead area 
being nearly 6 cm. in length. The control slits were beginning to 
heal. 
On account of the writer’s absence from Arkansas, the inoculated 
branches were not again examined until April 1, 1915. At that time 
the inoculated slit and control sht on 1-year-old twigs were not to be 
found, the twigs having been removed when the trees were pruned 
in March. The remaining cankers were the same size and apparently 
in the same condition as in the preceding autumn. The blackened 
bark presented the same sunken appearance and was still joined to 
the bark of the adjacent apparently healthy portions of the branch. 
By May 10 there was no change in the general appearance of the 
cankers except that the blackened bark was no longer connected 
with the adjacent uninjured bark. There was a distinct fissure run- 
ning entirely about the cankers, separating the blackened bark from 
the adjacent bark except at the extreme ends of the cankered area. 
This isolation of the dead bark was undoubtedly due to the fact 
that the branch had resumed growth, whereas the fungus had not. 
By May 21 the delimiting fissure was more pronounced, though 
the blackened bark was not wholly isolated. On this date the 
cankered branches were cut off, brought into the laboratory, and 
placed in moist chambers. At the end of 24 hours acervuli of the 
fungus appeared in all three of the cankers. Cultures from the 
conidia showed all the characters of Glomerella cingulata. Three 
of these cankers and one control were photographed and are shown 
in Plate V, figures 1, 2, and 3. 
Another series of inoculations was made in Arkansas on June 18, 
1915. The same technique was employed as in the experiments of 
1914. The spores used in the inoculations were ascospores from cul- 
tures made from a canker on June 4 and conidia from cultures made 
from a canker on May 21. The plan of the experiment was as 
follows: 
Three slits were inoculated with ascospores. 
Three slits were inoculated with conidia. 
Three slits were not inoculated. 
This plan was carried out on three varieties—Ben Davis, Jona- 
than, and Missouri. The moistened cotton covering the slits was 
removed on June 23. Only 2-year-old branches were employed. The 
weather was cool and accordingly not very favorable to the growth 
of the fungus. 
On July 8 all of the control slits were beginning to heal. In the 
case of the Ben Davis there was a band of dark sunken bark ex- 
tending a distance of 2 mm. about each inoculated slit. About the 
