Diseases of Plants 301 
materials. Their growth is 
favored by an abundance 
of moisture and warmth. 
The prevention of damp- 
ing off depends largely on 
the use of proper methods in 
growing seedlings. Do not 
use soil so rich that the plants 
are forced too rapidly. Give 
the seedlings space, both by 
proper sowing and by prompt 
thinning and transplanting. 
Supply water only according 
to the needs of the plants ; 
mix sand with the soil to 
help the drainage; regulate 
the temperature and venti- 
late the frames to harden 
the seedlings. With such 
precautions, damping off will 
seldom be serious. If it 
appears in flats, discard the 
entire flat and plant new 
seeds in less rich soil, or 
R. F. Poole, N. J. Expt. Sta. 
Fic. 169. Portion of a corn plant 
badly infected with corn smut. The 
diseased parts or the entire diseased 
plants should be cut off and de- 
stroyed. 
select healthy plants from uninfected parts of the flat 
and transplant them to a new flat with fresh earth less 
rich in humus. 
CORN SMUT 
One can readily detect the presence of this fungus, be- 
cause of the prominent and sometimes enormous swell- 
