Florida Agricultural Experiment Station


 CONTROL
 The injuries from Diplodia may be lessened by not growing
 cotton repeatedly in the same field, and by reducing, as far as pos-
 sible, all injuries to the bolls caused by bacterial blight, anthrac-
 nose, the boll weevil and other insects, and by cultural implements.

 ANTHRACNOSE
 Anthracnose is caused by the fungus Glomerella gossypii
 (South.) Edg., or, as it was formerly known in its asexual stage,
 Colletotrichum gossypii South. Anthracnose occurs in Florida
 and was formerly the cause of a great deal of damage to cotton,
 as high as 90 percent loss of bolls having been reported from some
 fields. During the past three years, however, it has been ex-
 tremely hard to find, and losses from it have been negligible.
 Though varying widely in severity from year to year in individual
 localities, the annual loss from this disease for the entire South,
 as reported by the United States Department of Agriculture, av-
 erages about 150,000 bales. The fungus over-winters in or on
 the seed or in decaying cotton debris in the field. The latter meth-
 od of over-wintering does not now appear to be of the importance
 once attributed to it, and the fact that the disease is largely seed-
 borne renders control an easier matter. From over-wintered fun-
 gus material in or on the seed the disease is spread to the young
 seedlings. As later growth appears the fungus attacks leaves,
 stems and bolls, the greatest injury occurring on the bolls. The
 fungus forms spores in large numbers on diseased bolls and often
 on the seed themselves. The spores are scattered to the lint and
 seed of healthy bolls in the field. Furthermore, the lint from a
 few diseased bolls is sufficient to contaminate a great many seed
 at the gin. Thousands of spores have been found on seed which
 to the naked eye appeared healthy. The spores are comparatively
 short-lived, however, and only a few survive longer than one year
 in stored seed.

 SYMPTOMS
 The young seedlings which develop from seed affected with an-
thracnose may damp-off and die or may merely show lesions on the
cotyledons. The damping-off by anthracnose resembles the damp-
ing-off caused by Rhizoctonia and other fungi, and refers to the
rotting off of the young seedling at or below the ground level.
Oftentimes the seed fail to germinate or the seedling is entirely