Cause and symptoms

Title: Wet rot of vegetable crops
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00066871/00001
 Material Information
Title: Wet rot of vegetable crops
Series Title: Plant Pathology Fact Sheet PP-11
Physical Description: Book
Language: English
Creator: Kucharek, Tom
Simone, Gary W.
Affiliation: University of Florida -- Florida Cooperative Extension Service -- Department of Plant Pathology -- Institute of Food and Agricultural Sciences
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: 1979
Spatial Coverage: North America -- United States of America -- Florida
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00066871
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 51338055

Table of Contents
    Cause and symptoms
        Page 1
        Page 2
Full Text

Plant Pathology Fact Sheet

Wet Rot of Vegetable Crops

Tom Kucharek,Professor and Extension Plant Pathologist, Department of Plant
Pathology; and Gary Simone, Professor and Extension Plant Pathologist, Retired,
Department of Plant Pathology, University of Florida, Gainesville. 1980; Revised
October 1999
Florida Cooperative Extension Service/ Institute of Food and Agricultural Sciences/ University of Florida/ Christine Waddill, Dean

Cause and Symptoms

Wet rot, also known as blossom blight
or whisker rot of vegetable crops, is primarily
a disease of flower parts and fruit. Squash, okra,
southern peas and sometimes cucumbers and
peppers are the chief vegetables affected. Other
hosts of this disease include althea (Rose-of-
Sharon), hibiscus, cotton and peanut. Yellow
summer squash types seem to be more suscep-
tible than other squash types. Southern pea cul-
tivars that are prone to lodging or that produce
pods a short distance above the ground are
more susceptible to wet rot.

This disease is caused by the fungus
Choanephora cucurbitarum. It may be classed as
a weak parasite since fruit invasion follows
passively after fungal colonization of spent
flower parts (petals and sepals) or behind in-
sect injury. Spores of the causal fungus have
been shown to over-season in soil and in asso-
ciation with susceptible crop debris. Wind dis-
semination of spores has been implicated and
is thought to be responsible for transportation
of the primary inocula (spores) of this fungus
onto squash. Secondary spread of this disease
in the field has been attributed to movement of
spores by various insects as well as wind. Bees
and the striped and spotted cucumber beetles
move spores of this fungus from flower to
flower in the squash crop. With southern peas,
wet rot incidence has been highly correlated
with cowpea cuculio injury. Dense plantings

of southern peas favor high populations of the
cowpea cuculio and subsequently have a higher
wet rot incidence. Puncture wounds from
cuculio feeding are thought to provide addi-
tional avenues of entry for the causal fungus.

Wet rot is most severe during warm, ex-
cessively wet periods. With southern peas, for
instance, dry weather limits this disease to the
corolla of the flower. Wet weather results in
progression of disease from the flower to the
pod and often to the peduncle. Symptoms of
wet rot are similar on all crops. Flower infec-
tion prior to pollination produces a blossom
blight. However, it is more common to see the
fungus colonize flower parts after fruit set. The
dark grey to black mold is first to appear on
flower parts (Fig. 1). Later the fungus advances
into the fruit. (Figs. 2 & 3). The fungus produces
a profusion of black spheres (sporangia) and
eventually rot progresses into the fruit. Wet rot
can be a postharvest problem, occasionally, es-
pecially on southern peas.


Control of wet rot is difficult. However, certain
measures can be used to reduce this problem.
1) Plant on well drained soils. 2) Avoid exces-
sive plant populations. 3) When spraying fun-
gicides use a nozzle arrangement and spray
pressure that will deposit spray within the
canopy 4) On southern pea, maintain adequate
control of the cowpea cuculio. 5) In small
plantings or gardens, hand removal of flower


parts, particularly squash, after fruit set will re-
duce this problem. 6) Avoid picking southern
peas when they are green and storing them
under wet conditions.

Figure 1. Wet rot fungus on okra flower.

Figure 2. Wet rot fungus on southern pea

Figure 3. Wet rot fungus on squash fruit.

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