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Group Title: Mimeo report - Gulf Coast Station - 58-5
Title: Physiological bud rot of gladiolus
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00067648/00001
 Material Information
Title: Physiological bud rot of gladiolus
Series Title: Gulf Coast Station mimeo report
Physical Description: 2 leaves : ; 28 cm.
Language: English
Creator: Woltz, S. S
Gulf Coast Experiment Station (Bradenton, Fla.)
Publisher: Gulf Coast Station
Place of Publication: Bradenton Fla
Publication Date: 1958
 Subjects
Subject: Gladiolus -- Diseases and pests -- Florida   ( lcsh )
Gladiolus -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: S.S. Woltz.
General Note: Caption title.
General Note: "April 1958"--Leaf 2.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067648
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, Board of Trustees of the University of Florida
Resource Identifier: oclc - 71435180

Table of Contents
    Copyright
        Copyright
    Cause
        Page 1
    Preventive measures
        Page 1
        Page 2
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





GULF COAST STATION MIMEO 3Z~ORT 58-5


Physiological Bud Rot of Gladiolus

S.S. Woltz, Assistant Horticulturist


The recent appearance of physiological bud rot of gladiolus (not
Botrytis rot) has suggested that a summary of available information may
be useful and timely.

Cause

As indicated in Gulf Coast Station Mimeo Report 56-2 (1956) the cause
of bud rot is considered to be a lack of adequate calcium in the flower
spike. The treatments suggested in that report will be reviewed and addi-
tional information included. Because of the speed with which the spike de-
velops, temporarily low levels of calcium in the soil solution will contrib-
ute to the appearance of the disorder. Excesses of other nutrient elements
in relation to calcium and an unusually rapid rate of growth are also caus-
ative factors. Thus, predisposing conditions include (1) excess rainfall
or even moderate rainfall at a critical period; (2) periods of warm weather;
(3) low levels of available calcium in the soil due either to failure to
apply or leaching losses and; (4) the presence of relatively large amounts
of other nutrient elements especially nitrogen, potassium and magnesium.

Field experiments have shown significantly less bud rot on limed as
compared with unlimed plots. Calcium deficiency of gladiolus grown in sand
cultures in the greenhouse caused a bud rot in Elizabeth the Queen and
Hopman's Glory varieties similar to physiological bud rot. The edges of
the florets became water-soaked and then dried up. Florets did not open
well but remained cupped. In severe cases of calcium deficiency the spikes
wilted and crooked. "Topple' of gladiolus (breaking over of spikes as
they bloom in the vase) is also a result of insufficient calcium in the
spikes.

Preventive Measures

Since the climate (temperature and rainfall) plays a large part in
producing the disorder, methods of prevention should be practiced with
greater emphasis during periods of higher temperatures and increased rain-
fall. The first step is to insure a good supply of calcium in the soil
by the application of liming materials and gypsum. Dolomitic limestone
is preferred since it does not raise the pH so radically and persists in
the soil over a longer period of time. The most desirable pH range is
6.0 to 6.5 but values down to 5.5 and up to 6.7 are usually not serious.
Ordinary superphosphate fortunately contains considerable calcium.

In addition to or as a substitute for the liming material when the
pH is already high, it is a good practice to apply 10Q0p-'iSd pounds of
gypsum per acre to provide calcium that will be rath p quickly' lable
during the season. i

Probably the most important preventive method s to say th ant-
ing with calcium nitrate or calcium chloride three 0i times b een
the time spikes start to appear and flower harvest b ns. The n. ecmended
concentrations are four pounds of calcium nitrate or tAp9 s calcium
chloride per hundred gallons. These materials are compatible~Lh common
fungicides and insecticides. A non-ionic wetting agent such as Triton
X-100 should be used at the rate normally recommended for spray applica-
tion.





GULF COAST STATION MIMEO 3Z~ORT 58-5


Physiological Bud Rot of Gladiolus

S.S. Woltz, Assistant Horticulturist


The recent appearance of physiological bud rot of gladiolus (not
Botrytis rot) has suggested that a summary of available information may
be useful and timely.

Cause

As indicated in Gulf Coast Station Mimeo Report 56-2 (1956) the cause
of bud rot is considered to be a lack of adequate calcium in the flower
spike. The treatments suggested in that report will be reviewed and addi-
tional information included. Because of the speed with which the spike de-
velops, temporarily low levels of calcium in the soil solution will contrib-
ute to the appearance of the disorder. Excesses of other nutrient elements
in relation to calcium and an unusually rapid rate of growth are also caus-
ative factors. Thus, predisposing conditions include (1) excess rainfall
or even moderate rainfall at a critical period; (2) periods of warm weather;
(3) low levels of available calcium in the soil due either to failure to
apply or leaching losses and; (4) the presence of relatively large amounts
of other nutrient elements especially nitrogen, potassium and magnesium.

Field experiments have shown significantly less bud rot on limed as
compared with unlimed plots. Calcium deficiency of gladiolus grown in sand
cultures in the greenhouse caused a bud rot in Elizabeth the Queen and
Hopman's Glory varieties similar to physiological bud rot. The edges of
the florets became water-soaked and then dried up. Florets did not open
well but remained cupped. In severe cases of calcium deficiency the spikes
wilted and crooked. "Topple' of gladiolus (breaking over of spikes as
they bloom in the vase) is also a result of insufficient calcium in the
spikes.

Preventive Measures

Since the climate (temperature and rainfall) plays a large part in
producing the disorder, methods of prevention should be practiced with
greater emphasis during periods of higher temperatures and increased rain-
fall. The first step is to insure a good supply of calcium in the soil
by the application of liming materials and gypsum. Dolomitic limestone
is preferred since it does not raise the pH so radically and persists in
the soil over a longer period of time. The most desirable pH range is
6.0 to 6.5 but values down to 5.5 and up to 6.7 are usually not serious.
Ordinary superphosphate fortunately contains considerable calcium.

In addition to or as a substitute for the liming material when the
pH is already high, it is a good practice to apply 10Q0p-'iSd pounds of
gypsum per acre to provide calcium that will be rath p quickly' lable
during the season. i

Probably the most important preventive method s to say th ant-
ing with calcium nitrate or calcium chloride three 0i times b een
the time spikes start to appear and flower harvest b ns. The n. ecmended
concentrations are four pounds of calcium nitrate or tAp9 s calcium
chloride per hundred gallons. These materials are compatible~Lh common
fungicides and insecticides. A non-ionic wetting agent such as Triton
X-100 should be used at the rate normally recommended for spray applica-
tion.









-2-

An approximate guide to the rate of dolomitic limestone application
is provided by Volk and Gammon (Circular S-39, Univ. of Fla. Experiment
Stations, Nov. 1951), as shown below


Soil Group


Per Acre Rate of Application of
Agricultural Limestone to Raise
the pH 1.0 Unit


Scrub land sands and white sands
in general . . .

Eigh pine land fine sands and light
gray flatwoods sands . ...

High pine land loamy fine sands and
medium gray flatwoods sands .

High pine land sandy loams and dark
gray flatwoods sands and sandy
loams . . . .

Clay loams, clays and black mineral
soils, depending upon texture and
humus content . .


500 pounds


1,000 pounds


1,500 pounds



2,000 pounds



2,000-6,000 pounds


300 copies
April 1958


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