a fall stubble crop is less liable to smut infection than a crop
following summer fallow. The apparent explanation for this condition is
the fact that the summer fallow becomes infected with wind-blown spores,
while in a stubble crop the wind-blown spores, as well as those
originating from the previous crop, are buried in plowing.

"If clean seed or properly treated seed had been used by all farmers we
should never have had a smut problem. High per cents. of smut indicate
either soil infection or imperfect treatment. The principle of the
chemical treatment is to use a poison which will kill the superficial
spores of the smut and not materially injure the germinating power of
the seed. The hot-water treatment is only recommended when one of the
chemical 'steeps' is not effective.

"Certain cultural practices are beneficial in reducing the amount of
smut in all cases, while the value of others depends to some extent upon
the source of the smut spores. The factors which always influence the
amount of smut are the temperature of the soil during the germinating
period, the amount of soil moisture, and the depth of seeding. Where
seed-borne spores are the only sources of infection, attention to the
three factors mentioned will give the only cultural practices for
reducing the amount of smut.

"Early seeding has been practised by various farmers, and they report a
marked reduction in smut.

"The replowing of the summer fallow after the first fall rains is
generally effective in reducing the amount of smut.

"Very late planting--that is, four or five weeks after the first good