Bulletin 208, Cucumber Diseases in Florida


ledons of seedlings and occasionally kills the young plants soon
after they are out of the ground. (Fig. 24.) The disease causes
severe losses in transit. The rot develops rapidly and can be
easily distinguished from the soft bacterial rots, since it is rather
firm and of a darker color. The rotted areas are also speckled
with the pycnidia and perithecia (spore-bearing parts of the
fungus) which are buried in the tissue just under the epidermis.
The disease is spread by wind and rain and is favored in its
development by warm, moist weather conditions.
 Description: The spots on the leaves are usually of a brownish
black color, circular, and often are 1/4 inch in diameter. The
tissue rapidly dries out and becomes wrinkled or cracks and falls
away. When an infection is located near the petiole of a cotyle-
don the whole cotyledon is killed. In a particular field 18 per-
cent of the seedlings were killed before they developed any true
leaves. The wilt has not been observed as important in Florida.
 The lesions of the fruit are at first oval to circular and are
greasy-green in color, later becoming dark brown. The rot de-
velops within the fruit and the whole fruit becomes darker col-
ored and soft but not of a slimy consistency. On this rotted fruit
the spores of the fungus are developed in small black structures,
pycnidia and perithecia.
 Control: Seed treatment should be practiced to kill the black
rot organism on the seed.
 Bordeaux spray, 4-4-50, or copper-lime dust, 80-20, will control
the disease in the field and careful handling during picking and
packing so as not to bruise the fruit will help materially in con-
trolling the disease in transit.

 STEM ROT OF CUCUMBERS
 This disease is caused by the fungus Sclerotinia sclerotiorum
(Lib.) Massee. It is not a common disease, having been found
only in scattered fields over the state during the past few years.
It was found both in the field and in greenhouses.
 Plants are attacked at any stage of development, usually on the
stem near the soil line of the younger plants and on the fruits of
the older plants. The principal damage is done in transit when
diseased fruits are packed for shipment. The fungus develops
rapidly in transit, resulting in a watery soft rot.
 This is the same fungus which causes a common disease of let-
tuce known as drop, and the destructive disease of celery known