42 
BULLETIN 1284, U. S. DEPARTMENT OF AGRICULTURE 
obtained by Kulkarni and those of the writers. The three plants 
infected with SphacelotJieca sorgJii may have been plants of some other 
variety; also Dwarf Yellow milo may be somewhat susceptible to 
SpJiacelotlieca cruenta, al ftiough Potter (91) and Reed (97) obtained no 
infection. 
Some preliminary experiments were undertaken to ascertain what 
factors might be involved in the resistance of milo and feterita. It 
was thought that the resistance might be chiefly due to varietal 
differences of a chemical and physiological character. On the other 
hand, it is possible that certain morphological differences in the 
germinating seed may account for the consistent absence of smut in 
these varieties. 
The first experiments were conducted in 1916 at Manhattan, 
Kans., and consisted in the removal of the very thin sheath from the 
plumule and the application of spores or conidia to the sprouts. 
It was a difficult matter to remove the sheath without seriously 
injuring the young plumule. The operation was performed when the 
plumule of the germinating seed was 2 to 3 millimeters long. After 
the sheaths were removed the plumules were dusted with spores 
and with sporidia grown in a carrot decoction, after which the 
germinating seeds were placed in soil in small flowerpots. The 
plumules in most instances were unable to emerge through the soil. 
Instead, they curled up beneath the surface and were unable to 
break through even the thinnest soil covering. By loosening the 
soil, however, the young plants were able to emerge, but it was 
several weeks before the seedlings recovered from the injury. After 
they were transplanted to the field, they soon became normal in 
appearance and vigor. 
Other experiments were conducted in which the germinating 
seed was subjected to ether fumes from three to five minutes and 
then inoculated. After treatment and inoculation, the germinating 
seeds were planted in flowerpots and transplanted to the field three 
or four weeks later. Unfortunately, very few of these seeds survived 
the ether fumes. In those which did survive no smut developed. 
The results obtained are presented in Table 11. 
Table 11. — Effects of mutilation and etherization of germinating kernels of various 
sorghums before inoculation with covered kernel smut at Manhattan, Kans., 
in 1916 
Experiment 
Treatment and variety 
Number of 
plants 
Sur- 
viving 
In- 
fected 
No. 1 
Plumule sheath removed, dusted with spores: 
Red Amber sorgo, S. P. I. No. 17548 


12 
2 
3 
1 
13 
8 
10 
2 
2 
4 
Feterita, C. I. No. 182 
Standard White milo, C. I. No. 352 

No. 2 
Plumule sheath removed, inoculated with sporidia and spores: 
Red Amber sorgo, S. P. I. No. 17548.. 
2 
Feterita, C. I. No. 182 
1 
Standard White milo, C. I. No. 352. 

No.3 
Etherized three minutes, dusted with spores: 
Red Amber sorgo, S. P. I. No. 17548 

Feterita, C. I. No. 182 

Standard White milo, C. I. No. 352... 

No. 4 
Etherized five minutes, dusted with spores: 
Red Amber sorgo, S. P. I. No. 17548.... 

Feterita, C. I. No. 182. .. 

Standard White milo, C. I. No. 352 

