FAMILIAR FARM ENEMIES 
275 
Smuts and Rusts are the result of fungi which grow 
upon grains and grasses. The large balls of smut which 
grow upon corn stalks are the sacks containing the spores 
of the fungus. They become dry in July or August and 
the black powder is scattered when the puffs are struck. 
Oats and wheat have a smut which causes the blackheads 
noticeable at the time of heading. These heads are often 
called blasted. As much as ten per cent of the crop may 
Fig. 195.—Stages of boll weevil. 
be destroyed by this form of fungus. The very fine 
threads grow inside the stalks until the grain begins to 
head, and the black spores in the form of powder are pro¬ 
duced. Rusts are usually found during a hot rainy sea¬ 
son, in the form of little red pockets on the surface of 
wheat or oat leaves. These may be so thick that the red 
dust rises in clouds when the grain is cut, or the clothes 
will become covered when walking through a field in¬ 
fected with rust. The grain of rusted plants shrivels, and 
