Treatment of Cotton Seed 
25 
TABLE IX 
Per Cent of Anthracnose and Germination in Cotton Seed Which Has 
Been Subjected to Preliminary Drying at 40-55° C. and Sub¬ 
sequent Heating at 70° C.* 
Exp. 
No. 
Lot 
No. 
Temp, of 
Prelim. 
Dryin g 
Deg. C. 
Time of 
Prelim. 
Drying 
Hours 
Temp, of 
Heating 
Deg. C. 
1 
1 
45-50 
72 
Not 
heated 
2 
45-50 
72 
70-75 
3 
45-50 
72 
70-7.5 
2 
1 
45-50 
72 
67-74 
2 
45-50 
72 
67-74 
3 
45-50 
72 
67-74 
3 
1 
50-55 
24 
70-73 
2 
50-55 
24 
70-73 
3 
50-55 
24 
70-73 
4 
1 
40-45 
48 
70 
5 
1 
40-45 
24 
70 
G 
1 
40-45 
24 
70-73 
2 
40-45 
24 
70-73 
7 
1 
40-45 
24 
70-73 
Time of 
Heating 
Per Cent of Seeds 
Developing Dis¬ 
eased Seedlings 
Per Cent of Seeds 
Germinated 
Hours 
Treated 
Untreated 
Treated 
Untreated 
Not 
22 
84 
heated 
24 
6 
95 
48 
0 
100 
24 
0 
0 
92 
94 
48 
4 
0 
96 
94 
72 
0 
0 
90 
94 
24 
2 
6 
98 
98 
48 
0 
6 
100 
98 
72 
0 
6 
94 
98 
72 
0 
90 
72 
0 
10 
88 
98 
48 
50 
86 
84 
96 
72 
6 
86 
92 
96 
72 
24 
64 
92 
94 
*In Experiments 1 to 3, seed of 1919 crop was used; in Experiments 4 and 5, seed of 1920 crop; in 
Experiments 6 and 7, seed of 1921 crop. Experiments 1 to 3 were done in a gas oven. Seed used in 
Experments 6 and 7 was 4 months old; that in Experiments 2 and 3 was 13J^ months old. 
It is evident that even after the seed have been dried at 45° C. a tem¬ 
perature of 70°C. is not sufficiently high to kill anthracnose in every in¬ 
stance even when the treatment is prolonged to 72 hours. All the tests 
except Experiments 6 and 7 were made at a time when the fungus was 
losing its viability from ageing as indicated by the behavior of check lots 
of untreated seed. Seed used in Experiments 1-5 was 10 to 16 months old 
when treated, while that of Experiments 6 and 7 was only 4 months old. 
The treatment proved to be much less effective with the young four months 
old seed of the 1921 crop than with the 10 to 16 months old seed of the 
1919 and 1920 crops. Germination of treated and untreated seed are seen 
to compare favorably. 
Rather than prolong the heating at 70° C. beyond a 72 hour period, it 
seemed better to try the effects of higher temperatures. In these, as in 
previous tests, the seeds were subjected to a preliminary desiccation before 
applying the higher temperature. The results of these tests, are presented 
in Table X. 
