Florida Agricultural Experiment Station


anywhere on the cotyledons and are usually not fatal to the plant
unless they are located at the base of the cotyledon. From here
it readily attacks the bud, killing the seedling.
 The lesions on the cotyledons are small, sunken, circular to oval
and at first darker in color than the surrounding tissue. Later the
tissue dies and becomes brown. As soon as the true leaves develop
they are subject to infection and the spots appear upon them
when about a week old. At first only a small water-soaked, circu-
lar area is evident. The spot enlarges and becomes limited in
extent by the veins of the leaf. (Fig. 13.) It varies in size from
1/16 to 1/2 inch in diameter. It is very seldom circular or oval but
rather angular in outline, being three-, four-, or five-sided depend-
ing on the surrounding veins.
 The spots are most easily detected in the morning when the
dew is still on the plants. They are water-soaked and of a darker
green color than the remainder of the leaf and are practically the
same on each side of the leaf. If one examines these spots at this
time there can be found milky white ooze in the form of small
drops around the spots. This ooze, known as exudate, is liquid
from the leaf teeming with bacteria and appears whitish be-
cause of their presence. As the leaves grow older the spots do not
enlarge to any great extent and after several days the central
areas become dry and fall out or are knocked out by rains, leaving
the leaves in a ragged condition. (Fig. 14.) For this reason the
disease is often referred to as the shotholee" disease.
 On the fruit the first indication of infection is the appearance
of small circular water-soaked spots, 1/16 of an inch or smaller
 in diameter. (Fig. 15.)
 They are found on any
 part of the fruit but
 most commonly on the
 upper surface. A lesion
 of this sort several days
 old enlarges slightly and
 a resinous formation ap-
 pears on its surface.
 There is very little out-
 ward development from
 this stage; instead the
 fruit begins to decay on
 the inside. From the
Fig. 14. General effect of angular leaf spot
 disease on the foliage of cucumbers. lesion on the surface a