62 
Journal of Agricultural Research 
Vol. II, No. i 
Table V. —Results of inoculation experiments of August jo on York Imperial and Ben 
Davis apple branches . 
York Imperial. 
Experiment No. 
Number of 
burned 
spots. 
Number of 
enlarged 
spots. 
Average 
width of 
enlarge¬ 
ments. 
Percentage 
of enlarged 
spots. 
JI 5 
*3 
Mm. 
I 
11 
93 
2 
I 
2 
3 ... 
102 
19 
1* 5 
19 
4 . 
65 
0 
0 
0 
5 . 
117 
2 
1 
2 
Ben Davis. 
5 ° 
18 
i- 5 
36 
29 
0 
0 
0 
34 
14 
3 
41 
5 i 
6 
2 
12 
43 
2 
2 
5 
Hyphse and spores of Alternaria were found on both of the spot enlargements of 
York Imperial apple experiment 5. 
The experiments of September 3 were carried on in an orchard at Arlington, Va. 
The trees selected were io-year-old York Imperials which were entirely free from 
foliage diseases. These trees were planted quite closely together, so that certain 
portions were protected from direct sunlight during the afternoon. Leaves partly 
shaded in this way were selected as the most favorable for successful inoculation. 
Experiment i. —The leaves were spotted with a heated rod, as in previous experi¬ 
ments, and without previous sterilization were thoroughly sprayed with distilled 
water containing thick masses of spores of Alternaria obtained from cultures from 
the spot enlargements in the experiments of July 19. 
Experiments.—T he leaves were spotted as in No. 1 and without sterilization 
were sprayed with distilled water. 
The weather during September was quite dry, but rains occurred with great fre¬ 
quency during October. 
The results on October 22 are shown in Table VI. 
Table VI.— Results of inoculation experiments of September 3 on York Imperial apple 
branches. 
Experiment No. 
Number of 
burned 
spots. 
Number of 
enlarged 
spots. 
Average 
width of 
enlarge¬ 
ments. 
Percentage 
of enlarged 
spots. 
I. 
127 
72 
71 
Mm. 
! 
I 
56 
2. 
16 
j I 
22 
i 
Cultures from the spot enlargements induced in both these experiments contained 
Alternaria in nearly every case. 
The experiments of September 9 were carried on in the laboratory. From a well- 
kept orchard York Imperial branches with perfect leaves were selected and the cut 
ends placed in a flask of distilled water. The material used in all five experiments 
