Suggestions for caladium disease control

Material Information

Suggestions for caladium disease control
Series Title:
Apopka ARC research report
Knauss, J. F ( James Frederick ), 1938-
Place of Publication:
Apopka Fla
University of Florida, IFAS, Agricultural Research Center
Publication Date:
Rev. ed.
Physical Description:
5 leaves : ; 28 cm.


Subjects / Keywords:
Caladium -- Diseases and pests -- Control -- Florida ( lcsh )
Tubers ( jstor )
Plant roots ( jstor )
Fungicides ( jstor )
government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )


General Note:
Caption title.
Statement of Responsibility:
J.F. Knaus.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
70922121 ( OCLC )


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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

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

(O ~k'


A. Bacterial

Erwinia carotovora

Erwinia chrysanthemi

B. Fungal

Sclerotium rolfsii

Botrytis spp.

Fusarium spp.

Pythium spp.

Phytophthora spp.?

Rhizoctonia spp.?

J. F. Knauss
University of Florida, IFAS \
Apopka ARC Research Report RH73-2 (Revise4)9C

\ r,.


For planting stock, always select the healthiest tubers harvested from

the previous year's crop. Because pathogens mentioned above survive

from one season to the next on infected tubers, selection of the best

tubers (those which have the least visible disease on them) for planting

stock will keep the initial pathogen population on tubers low. This

also aids in reducing disease development throughout the growing season.

Heat treatment of the planting stock at 1220F for 30 min. prior to

cutting into planting chips is of utmost importance and may be the

difference between success or failure of the crop. Proper heat treatment

will eliminate Pythium, Phytophthora, Sclerotium rolfsti and possibly



the other fungal pathogens from the tubers before planting. Heat-treated

tubers are much less likely to initiate disease by introduction into the

planting area of pathogens which are on or in the planting chips. TIhen

heat treating, however, make sure the temperature is maintained as close

to 1220F as possible and does not exceed this level during the 30 min.

treatment period. Constant observation of the thermometers during the

heat treatment process is important and worth every minute spent. After

the 30 min. heat treatment period, extract the tubers and cool immediately

in clean tap water* After cooling, allow the tubers to dry before cutting

into chips. Do not place these.heat-treated tubers where they may become

recontaminated with caladium plant pathogens before planting. If you are

heat treating tubers for the first time do not be alarmed if after planting,

the pieces seem a little slow in germinating. Heat treatment has been

shown to delay germination of caladium chips for approximately 7-10 days

with no adverse effect upon growth and production. After heat treatment

and cutting the tubers, dust chips with 10% Captan prior to planting.

Other materials which might be tried on a small scale as a pre-plant

dust are 10% Difolitan, 5% Truban, or all the proceeding in combination

with 5% Benlate.

In fall after digging, wash tubers thoroughly and spray with or dip in

a solution containing 3 lb of Captan plus 200 ppm streptomycin/100 gal

of water. Other fungicides that may be tried on a trial basis as a

spray or a dip are Folpet (3 Ib) and Benlate (1 lb). tWhether these

will combine effectively and safely with the bactericide streptomycin

for use on caladiums has not yet been determined. Ten percent Botran

or Difolitan dusts have also been reported as satisfactory in controlling

storage rots of tubers. After digging, washing and chemically treating,

dry the tubers as rapidly as possible to prevent tuber decay.

k AAA ti>ar>mi 1nn nnmllrn of vtl a1 a+ f \ rnnlIna wat-pr.



A. Bacterial

Xanthomonas app.

Erwinia spp.?

B. Fungal

Pythium spp.

Phytophthora spp.

Sclerotium rolfsii

Rhizoctonia spp.

Fusarium spp.


Prepare the planting area properly for fumigation. Level the soil so

the boundary areas slope away from the area to be planted. Make sure

the drainage ditches are large enough to handle all anticipated run-off

from the field. These practices will help prevent wash-ins which tend to

recontaminate fumigated land- Fumigate the planting area. Plant

fungicide or dolomite-dusted chips obtained only from your healthiest

appearing, heat-treated tubers.

The following information on field application of fungicides is to

be taken as preliminary and is largely the result of research conducted

in 1972 and on results obtained from research conducted on ornamental

foliage plants. This research is continuing so that within the coming

years specified recommendations can be made based on sound and thorough

Results. At present, it is felt that in-row spray treatments in the

plantinr furoaw oouplad with 1-2 band treatments at the base of the


plants during the growing season will prove to keep the root and crown

decay pathogens of caladiums under control. The following fungicides

and their stated concentrations on a 100 gal water basis have given safe

and effective control of the field caladium pathogens stated:

Pythium spp.

Truban 30 WP (12 oz)

Sclerotium rolfsii

Terraclor 75 WP ( 1 lb)
Fermate 76 WP (2 Ib)
Demosan 65 WP (1 Ib)

Rhizoctonia spp.

Benalte 50 WP (12 oz)
Terraclor 75 WP (1 lb)
Fermate 76 WP (2 lb)
Demosan 65 WP (1 lb)

In the foliage industry, Truban has been combined with either Benlate,

Fermate or Terraclor to produce a wide-spectrum soil fungicide. Benlate

should never be used alone as an in-row or band spray treatment and should

always be used in combination with Truban. The normal rate of application

for these soil fungicides is 1 pint/sq ft or 1 pint/each 3 feet of a 4

inch band or in-row treatment. To cut down on the amount of fungicide

suspension needed, it is safe to increase the fungicide concentration

by putting the same amount in 50 gal water and applying 1/2 pint/sq ft

or 3 feet of a 4 inch band or in-row treatment. Although higher fungicide

concentrations and corresponding lower application rates might be used,

it is not suggested because research has not yet determined whether this

would be safe to the caladium. Follow the chemical band applications

with 1/2 to 1 inch of irrigation water.


The only exception to following the chemical band application with

1/2 to 1 inch of irrigation water will be when either Sclerotium rolfsii

or Rhizoctonia are visibly attacking the basal portion of the leaves. In

this case, the band application should only be followed with a light

watering to wash the chemicals off the upper foliage.

Whenever possible, all the proceeding chemical band applications

should be done in the morning hours, with the later afternoon and evening

hours qs a second choice.