Florida Agricultural Experiment Station


stunted and weak for some time. After the plants attain a little
size the fungus is unable to attack them even though the weather
becomes favorable to the disease. By the time the plants have be-
come large enough to be chopped danger from the soreshin dis-
ease is past and a stand has or has not been established. Young
cotton plants injured by the soreshin disease are illustrated in
Fig. 7.
 CONTROL
 The damage caused by the soreshin disease in reducing stands
can be lessened by the planting of a bushel of seed to the acre, by
not planting too early, and by cultivating to allow the soil to dry
out and warm up more rapidly. Planting in ridges helps in drying
out and warming up the soil, since more area is exposed to the
sun's rays. So far as is known there is no successful means of
treating the seed to control this disease.

 DIPLODIA BOLL ROT
 The name Diplodia boll rot is derived from the name of the fun-
gus causing the disease, Diplodia gossypina Edg. This boll rot is
the most serious one occurring in Florida. Many fields in this
state have been observed where 50 percent of the bolls were worth-
less from this cause, and there is hardly a cotton field in the state
where it cannot be found. The damage to the crop as a whole in
the State of Florida during the wet season of 1928 was conserva-
tively estimated at 20 percent.
 The fungus is unable to penetrate uninjured tissue, but the
slightest wound or abrasion is sufficient to allow the fungus to en-
ter. Diplodia, after once entering a boll, develops very rapidly,
and only two or three days of humid weather are sufficient for the
fungus to completely rot the boll. The lesions caused by bacterial
blight and anthracnose on the bolls, especially the former, are com-
mon points of entry for Diplodia, as are also the punctures of boll
weevils and of other insects.
 Diplodia is capable of living in the soil for indefinite periods of
time on the decaying debris of cotton and other plants. From this
original source of infection the spores of the fungus are scattered
by the wind or other agencies to the bolls, where they germinate
and grow into the bolls, if they are the least bit damaged. The
rotted bolls produce great numbers of spores that are scattered
over the field and serve to infect other bolls. The seed produced
in such bolls are usually rotted and do not germinate. In germina-