Mar. 19, 1917 
Dissemination of Angular Leaf spot of Cotton 
463 
a high percentage of seed infection. These are labeled “Lots II-V,” 
Lot I being seed of the same lot planted on April 20 and remaining free 
from seedling infection. The other lots (VI-X) are Mississippi Cook 
seed grown on the Experiment Station farm under differing conditions 
the previous summer. 
On two sides of this triangular plot were cotton variety tests of the 
Station, and the disease was present upon these plants. To guard 
against insect activity in spreading the disease to the young seedlings and 
thus confusing the results, cages of cheesecloth were erected over 12 feet 
of a row of each lot of seed, giving an opportunity for the disease to 
appear under such protection if the bacteria were present upon or in the 
seed. The field was planted on August 12. The seed germinated 
quickly, and the seedlings began to appear above the ground by the 16th 
and 17th. On the 22d a careful examination was made of all the plants, 
but no disease was found. On the 28th 11 cases of cotyledonary infec¬ 
tion were found, and on September 1, 20 days after planting and 15 days 
after the cotyledons were spread, affording ample time for the appearance 
of the disease in view of our earlier work, the final counts were made. 
Of 34 diseased plants found, only one was beneath a cage; yet that one 
lends weight to the conclusion that seed infection does occur. The 
tabulated data by plots of each lot of seed follows in Table I. 
Table I .—Results of the infection of cottonseed by angular leaf spot 
Lot No. 
Plot No. 
Number of 
seedlings. 
Number diseased in— 
11 days. 
20 days. 
Total num¬ 
ber of 
seedlings. 
Total num¬ 
ber dis¬ 
eased. 
Percentage 
diseased. 
II. . 
III. 
IV. 
V. . 
VI. 
VII. 
VIII. 
IX. . 
X. .. 
1 
2 
3 
4 
„ 5 
Cage. 
6 
7 
Cage. 
8 
^ 9 
Cage. 
10 
11 
12 
Cage. 
13 
14 
1 5 
16 
Cage. 
17 
18 
19 
20 
Cage. 
Grand total. 
820 
4,926 
h 743 
586 
468 
207 
3 ? ° 2 3 
3 , 543 
179 
2, 622 
700 
'86 
2, 884 
1,242 
1,402 
117 
142 
2,030 
1, 150 
195 
145 
2, 002 
1,247 
3*678 
1,415 
16 
o 
o 
o 
o 
o 
4 
o 
4 
o 
o 
o 
o 
o 
o 
3 
o 
o 
o 
o 
o 
o 
1 
o 
o 
o 
o 
2 
7 
I 
I 
o 
o 
6 
4 
8 
o 
o 
o 
4 
o 
o 
o 
o 
o 
o 
o 
8, 75 ° 
I 
0. on 
6, 745 
14 
. 2 
3.408 
5 
. 14 
5.645 
18 
• 3 i 
142 
2,030 
1,490 
3,249 
3 , 6 7 8 
I , 43 1 
36 ,568 
7 -46 
o 
o 
o 
45 
