Apr. 15, 1914 
Experiments with Apple Leaf-Spot Fungi 
63 
was sterilized by treatment with alcohol and with merctiric-chlorid solution and the 
leaves were burned with a heated rod, as in previous experiments. In experiments 
1 to 4 the leaves were sprayed with distilled water containing, respectively, spores 
of Coniothyrium pirinum , Sphaeropsis malorum , Alternaria sp. from cultures made 
from spot enlargements in experiment 4 of July 28, and Coryneum foliicolum. In 
experiment 5 the leaves were sprayed with sterile water only and considered as checks. 
All the branches were then placed under bell jars lined with wet filter paper. Under 
these conditions the leaves retained their color and turgor for 10 days and appeared 
to be as healthy as if they had been left on the tree. The results are given in Table 
VII. 
Table; VII .—Results of inoculation experiments of September 9 on York Imperial apple 
branches . 
Experiment No. 
Number 
of burned 
spots. 
Number of 
enlarged spots. 
Average width 
of enlargements. 
Percentage of 
enlarged spots. 
Sept. 
13. 
Sept. 
15. 
Sept. 
13. 
Sept. 
I S* 
Sept. 
13- 
Sept. 
Mm . 
Mm. 
IOI 
*5 
53 
I 
I 
15 
52 
94 
0 
11 
0 
I 
O 
12 
3 . 
“3 
52 
107 
I 
5 
46 
95 
4 . 
S3 
2 
9 
I 
i- 5 
2 
11 
5 . 
46 
I 
2 
I 
1 
2 
4 
The enlargements in experiment 3 were slightly larger than those in the other 
experiments. Coniothyrium was fruiting on the original spots in experiment 1, but 
not on the enlargements. 
Of 14 cultures from enlargements of experiment 1 made as in previous series of 
experiments, 6 developed the Alternaria, 1 developed Coniothyrium, 4 contained 
bacteria, and 3 were sterile. Of 11 from experiment 2, $ developed bacteria, 1 con¬ 
tained Alternaria, and 5 were sterile. From experiment 4, out of a total of 8 cultures, 
4 developed Alternaria, 3 contained bacteria, and 1 was sterile. 
In the series of experiments begun on September 17, York Imperial apple branches 
were used, as in previous experiments. All were placed under bell jars in the labora¬ 
tory. Experiments 1 and 2 were performed in the same manner as the corresponding 
numbers in the experiments of September 9. In experiment 3 the leaves were 
sprayed with distilled water containing spores of Monochaetia mali , and in experiment 
4, the check, they were sprayed with sterile water. All leaves were sterilized, and 
spots were burned upon them, as in previous experiments. The results on September 
23 are given in Table VIII. 
Table VIII .—Results of inoculation experiments of September 17 on York Imperial 
apple branches . 
Experiment No. 
Number of 
burned 
spots. 
Number of 
enlarged 
spots. 
Average 
width of 
enlarge¬ 
ments. 
Percentage 
of enlarged 
spots. 
87 
1 7 
Mm. 
I 
20 
2 . 
167 
32 
2 
*9 
3 . 
65 
3 
I 
5 
* 
53 
10 
2 
*9 
Out of a total of 18 cultures from the spot enlargements of experiment 2,17 contained 
Alternaria and 1 developed bacteria. In experiment 1 Coniothyrium fruits appeared 
on every spot, but there was none on the enlargements. As before, the favorite place 
