20 
~ N . C. Experiment Station 
TABLE IY 
Effect of Temperature on The Daily Development and Percentage of 
Anthracnose on Seedlings Growing From Seeds Inoculated With A 
Suspension of Conidia of Glomerella Gossypii. 
Days From Time 
Put to Germinate 
2 
14 
2 
5 
6 
7 
8 
14 
Exp. 
Temp. 
No. 
Deg. 
C. 
Per Cent 
Germination 
Per Cent Anthracnose 
1 
1 
20 
60 
60 
0 
0 
0 
10 
60 
60 
1 
25 .5 
60 
60 
0 
30 
60 
60 
60 
60 
1 
30.5 
70 
70 
0 
70 
70 
70 
70 
70 
1 
35 
90 
90 
0 
0 
0 
0 
0 
0 
TABLE Y 
Effect of Temperature oX The Daily Development and Percentage of 
Anthracnose on Seedlings Atomized With A Suspension of 
Conidia of Glomerella Gossypii. 
Experiment No. 2 
Experiment No. 3 
Temp. 
Deg. 
Days From Time Put to Germinate 
Days From Time Put to Germinate 
C. 
2 
3 
4 
6 
12 
2 
3 
4 
6 
a 
a 
a 
a 
20 
0 
0 
0 
30 
70 
0 
0 
10 
60 
25.5 
0 
0 
60 
70 
70 
0 
80 
100 
100 
30 
0 
30 
50 
60 
60 
0 
100 
100 
100 
33 
0 
60 
60 
90 
35 
0 
0 
0 
0 
0 
a Temperature of this lot varied between 18 and 25° (18° for about 18 hours and 25° for 6 hours). 
It is evident that the temperatures of 25 and 30° C. are very near the 
optimum for the development of anthracnose on seedlings grown under the 
conditions of these tests. The disease appeared on most of the seedlings 
incubated at 20° C. but at this temperature it developed more slowly and 
did not destroy the seedling as quickly as at 25 and 30° C. This slow 
development of the disease at 20° is probably correlated primarily with the 
less rapid growth of the causal organism at that temperature. At 35° C., 
a temperature which inhibits growth of the fungus, anthracnose failed to 
develop. 
From the results of the several temperatures experiments described above, 
the following conclusions applying to the particular conditions of the tests 
may be set forth: 
1. Temperatures of 25 and 30° are not only very favorable for germina¬ 
tion of cotton seed and the subsequent growth of the seedlings but also 
closely approximate the optimum for growth in culture of the fungus caus¬ 
ing cotton anthracnose and for the development of the disease. 
