• TABLE OF CONTENTS
HIDE
 Copyright
 Curvularia diseases
 Stemphylium leaf spot
 Fusarium disease research
 Corms treatments
 Standard corm dip materials
 To control fusarium on jambo...
 To control fusarium on medium and...
 Soil treatment for disease...






Group Title: Mimeo report - Gulf Coast Station - 58-3
Title: Gladiolus disease research summary for 1957
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067754/00001
 Material Information
Title: Gladiolus disease research summary for 1957
Series Title: Gulf Coast Station mimeo report
Physical Description: 6 leaves : ; 28 cm.
Language: English
Creator: Magie, R. O ( Robert Ogden ), 1906-
Gulf Coast Experiment Station (Bradenton, Fla.)
Publisher: Gulf Coast Station
Place of Publication: Bradenton FL
Publication Date: 1957
 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: R.O. Magie.
General Note: Caption title.
General Note: "9/25/57"--Leaf 6.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00067754
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 - 73488817

Table of Contents
    Copyright
        Copyright
    Curvularia diseases
        Page 1
    Stemphylium leaf spot
        Page 1
    Fusarium disease research
        Page 1
    Corms treatments
        Page 2
    Standard corm dip materials
        Page 3
    To control fusarium on jambo corms
        Page 4
    To control fusarium on medium and small corms
        Page 4
    Soil treatment for disease control
        Page 4
        Page 5
        Page 6
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 Report 58-3


GLADIOLUS DISEASE RESEARCH SUMMARY FOR 1957

R. 0. Magie

Gladiolus production was severely reduced in some areas of the State
by fall drought and by unusually heavy rainfall in the spring. Fogs and rains
brought about more trouble thanyub~ta with Botrytis disease. However, leaf
spots caused by Curvularia and Stemphylium were less troublesome than usual.
Corm rot and spotting of corms by Curvularia continued to increase in severity
and prevalence. Over 40 acres of corms and cormels were destroyed by Curvu-
laria corm rot. The scabbing and spotting of corms by wet soil conditions
was unusually severe on some farms.

Highlights of the year's research include 1) good control of Fusarium
and better flower production with a new corm dip treatment, 2) outstanding
increases in flower production by removal of corm husks, 3) excellent con-
trol of Stemphylium leaf spot with Dyrene spray and 4) further knowledge on
methods of controlling soil diseases.

Curvularia Disease

New spray fungicides were tested on three farms for controlling Curvu-
laria leaf spot on Picardy and Corona planting stock and cormels. The dis-
ease did not develop enough in the plots to yield any results. However,
these tests indicated that Curvularia leaf spot is more easily controlled
when cormels are hot-water treated. Many cormel stocks carry the disease.

Curvularia is also carried on the husks of corms that appear to be
healthy. Plantings of such corms were a total loss in some cases where the
corms were not treated properly. Any of the standard treatments is better
than none but the organic mercury fungicides are most effective. For jumbo-
size corms, Ceresan M is recommended as a preplanting dip. Mix 1 pound in
100 gallons and soak for 5 to 10 minutes. Since Ceresan M does not dissolve
in water, the dip must be stirred constantly. For corms smaller than jumbo
size, use the 10 or 15 minute N.I.Ceresan treatment, 2 lb. per 100 gal.

Ceresan M and N. I. Ceresan are also effective against Stromatinia
and Fusarium diseases carried on corms.

Stemphylium Leaf Spot

A new spray material, Dyrene, manufactured by Chemagro Corporation, cnn-
trolled the leaf spot on Florence Nightingale much better than maneb and otb~h
fungicides. Dyrene will be available in some agricultural supply stores this
fall. One spray application per week of Dyrene 2 lb. per 100 gallons water
plus 2 oz. Triton X-100 is recommended for Stemphylium leaf spot control.
Spray applications should begin at the first sign of leaf spot, or by Janu-
ary 15 on susceptible varieties.

This spray is not recommended against the other leaf spots caused.by
Curvularia and Botrytis. Dyrene is believed to be compatible with 'other fun-
gicides and insecticides. If the plantings are to be sprayed td control Bo-,
trytis or Curvularia as well as Stemphylium, alternate maneb o0 zineb ,ith
Dyrene.

Fusarium Disease Research ;

It was reported a year ago that removing the husks from jumbo Picardy
corms before planting doubled the flower production and gave 50%7. mo~souid




Gulf Coast Station Mimeo Report 58-3


GLADIOLUS DISEASE RESEARCH SUMMARY FOR 1957

R. 0. Magie

Gladiolus production was severely reduced in some areas of the State
by fall drought and by unusually heavy rainfall in the spring. Fogs and rains
brought about more trouble thanyub~ta with Botrytis disease. However, leaf
spots caused by Curvularia and Stemphylium were less troublesome than usual.
Corm rot and spotting of corms by Curvularia continued to increase in severity
and prevalence. Over 40 acres of corms and cormels were destroyed by Curvu-
laria corm rot. The scabbing and spotting of corms by wet soil conditions
was unusually severe on some farms.

Highlights of the year's research include 1) good control of Fusarium
and better flower production with a new corm dip treatment, 2) outstanding
increases in flower production by removal of corm husks, 3) excellent con-
trol of Stemphylium leaf spot with Dyrene spray and 4) further knowledge on
methods of controlling soil diseases.

Curvularia Disease

New spray fungicides were tested on three farms for controlling Curvu-
laria leaf spot on Picardy and Corona planting stock and cormels. The dis-
ease did not develop enough in the plots to yield any results. However,
these tests indicated that Curvularia leaf spot is more easily controlled
when cormels are hot-water treated. Many cormel stocks carry the disease.

Curvularia is also carried on the husks of corms that appear to be
healthy. Plantings of such corms were a total loss in some cases where the
corms were not treated properly. Any of the standard treatments is better
than none but the organic mercury fungicides are most effective. For jumbo-
size corms, Ceresan M is recommended as a preplanting dip. Mix 1 pound in
100 gallons and soak for 5 to 10 minutes. Since Ceresan M does not dissolve
in water, the dip must be stirred constantly. For corms smaller than jumbo
size, use the 10 or 15 minute N.I.Ceresan treatment, 2 lb. per 100 gal.

Ceresan M and N. I. Ceresan are also effective against Stromatinia
and Fusarium diseases carried on corms.

Stemphylium Leaf Spot

A new spray material, Dyrene, manufactured by Chemagro Corporation, cnn-
trolled the leaf spot on Florence Nightingale much better than maneb and otb~h
fungicides. Dyrene will be available in some agricultural supply stores this
fall. One spray application per week of Dyrene 2 lb. per 100 gallons water
plus 2 oz. Triton X-100 is recommended for Stemphylium leaf spot control.
Spray applications should begin at the first sign of leaf spot, or by Janu-
ary 15 on susceptible varieties.

This spray is not recommended against the other leaf spots caused.by
Curvularia and Botrytis. Dyrene is believed to be compatible with 'other fun-
gicides and insecticides. If the plantings are to be sprayed td control Bo-,
trytis or Curvularia as well as Stemphylium, alternate maneb o0 zineb ,ith
Dyrene.

Fusarium Disease Research ;

It was reported a year ago that removing the husks from jumbo Picardy
corms before planting doubled the flower production and gave 50%7. mo~souid




Gulf Coast Station Mimeo Report 58-3


GLADIOLUS DISEASE RESEARCH SUMMARY FOR 1957

R. 0. Magie

Gladiolus production was severely reduced in some areas of the State
by fall drought and by unusually heavy rainfall in the spring. Fogs and rains
brought about more trouble thanyub~ta with Botrytis disease. However, leaf
spots caused by Curvularia and Stemphylium were less troublesome than usual.
Corm rot and spotting of corms by Curvularia continued to increase in severity
and prevalence. Over 40 acres of corms and cormels were destroyed by Curvu-
laria corm rot. The scabbing and spotting of corms by wet soil conditions
was unusually severe on some farms.

Highlights of the year's research include 1) good control of Fusarium
and better flower production with a new corm dip treatment, 2) outstanding
increases in flower production by removal of corm husks, 3) excellent con-
trol of Stemphylium leaf spot with Dyrene spray and 4) further knowledge on
methods of controlling soil diseases.

Curvularia Disease

New spray fungicides were tested on three farms for controlling Curvu-
laria leaf spot on Picardy and Corona planting stock and cormels. The dis-
ease did not develop enough in the plots to yield any results. However,
these tests indicated that Curvularia leaf spot is more easily controlled
when cormels are hot-water treated. Many cormel stocks carry the disease.

Curvularia is also carried on the husks of corms that appear to be
healthy. Plantings of such corms were a total loss in some cases where the
corms were not treated properly. Any of the standard treatments is better
than none but the organic mercury fungicides are most effective. For jumbo-
size corms, Ceresan M is recommended as a preplanting dip. Mix 1 pound in
100 gallons and soak for 5 to 10 minutes. Since Ceresan M does not dissolve
in water, the dip must be stirred constantly. For corms smaller than jumbo
size, use the 10 or 15 minute N.I.Ceresan treatment, 2 lb. per 100 gal.

Ceresan M and N. I. Ceresan are also effective against Stromatinia
and Fusarium diseases carried on corms.

Stemphylium Leaf Spot

A new spray material, Dyrene, manufactured by Chemagro Corporation, cnn-
trolled the leaf spot on Florence Nightingale much better than maneb and otb~h
fungicides. Dyrene will be available in some agricultural supply stores this
fall. One spray application per week of Dyrene 2 lb. per 100 gallons water
plus 2 oz. Triton X-100 is recommended for Stemphylium leaf spot control.
Spray applications should begin at the first sign of leaf spot, or by Janu-
ary 15 on susceptible varieties.

This spray is not recommended against the other leaf spots caused.by
Curvularia and Botrytis. Dyrene is believed to be compatible with 'other fun-
gicides and insecticides. If the plantings are to be sprayed td control Bo-,
trytis or Curvularia as well as Stemphylium, alternate maneb o0 zineb ,ith
Dyrene.

Fusarium Disease Research ;

It was reported a year ago that removing the husks from jumbo Picardy
corms before planting doubled the flower production and gave 50%7. mo~souid







corms. Similar results were obtained again this past season, using another
stock of Picardy and June Bells. The cost of removing the husks would be
repaid handsomely if the flower production were increased only 10%. The
results of these tests in both years are s* outstanding that growers should
make small tests with their own corms and with different varieties.

In both years the corms were dehusked in September about one week.-
before planting and dusted with Spergon 247. powder. No other treatment
was given to the husked corms. These were grown side by side with Sper-
gon-dusted check corms and with unhusked corms treated in N.I*Ceresan so-.
lution for 5 minutes as recommended just before planting. The test plots-
were replicated. Flower production from N.I.Ceresan and check corms was
half that from the husked corns. These-results indicate that most of the
disease infections are carried in the husks. They certainly emphasize-the-.
importance of adding a good penetrating agent like Triton X-100 to the
corm dip.

Nematode infection of corms is commonly.found and may be Important'
in bringing about Fusarium rot. In one test using Picardy and Valeria,
flower production was increased over untreated check corms by 33% just by
soaking the corms for 15 minutes in one quart of Orthophos *(parathion)- per ...-
100 gallons of water before planting. The number of corms harvested-from
the test plots was not affected by the parathion treatment, but the size
of Picardy-corms was increased 26.. It is recommended that one pint of-en-ul-
sifiable parathion.containing 4 lb. active ingredient per gallon be-added
to each 100 gallons of dip. Since parathion is inactivated in alkaline so-
lutions, it is suggested by the manufacturer that parathion would not be ef-
fective in Dowicide B solution which has a pH of 9 to 10.

Hot-water treatment of cormels is giving unusually good results .in
high production of spikes and corms. However, a few varieties are killed
by the heat, so a test should be made on a small lot along with two stand-
ard varieties as checks before any new variety is treated in large amounts.
Directions for the hot-water treatment are given in Gulf Coast Station
Mimeo Report No. 57-4.

Corm Treatments

Practically all growers treat corms with a fungicide to control dis-
eases but probably no two growers treat corms in the same way. Some treat
before planting, while others. treat before storage and again before plant-
ing. The.kind of fungicide used, the concentration and the treating time
also vary from farm to farm. The degree of disease control is better on
some farms than on others but the differences are not often due to the
corm treatments used.

Each of the three corm treatment fungicides, N. I. Ceresan, Dowi-
cide B and captain, is giving fair disease control on some farms. New ma-
terials are being tested as corm dips each season in order to obtain better
control, especially of the Curvularia and Stromatinia diseases. The best
control of these diseases, as well as of Fusarium, is obtained with organic
mercury fungicides. Dowicide B and captain have been largely substituted
. for the organic mercury N.I.Ceresan, because this compound sometimes injures
the jumbo corms and reduces flower yields.

Two new organic mercury compounds, Thimerosal and Panogen, have
proved, to be just as effective against Fusarium as N.I.Ceresan and much-
safer. They can even be used as prestorage dips. They are also effec-
tive against Curvularia and Stromatinia diseases. However, until they




-3-


have been tested on commercial farms, no general recommendation can be made.

Thimerosal, a white powder, easily soluble in water, is the active
ingredient of "Merthiolate". Thimerosal is recommended for limited trial
as a preplanting dip for gladiolus corms. For the 15-minute dip, use 3
ounces in 100 gallons of water plus 2 ounces of Triton X-100, or any e-
qually good penetrating-wetting agent. For a 30-minute dip, use 2 ounces
per 100 gallons. Equally good results were obtained when Thimerosal was
used as a ten-minute restore dip, with 2 ounces of the powder and 2 oun-
ces of Triton X-100 in 100 gal. Thimerosal was remarkably effective as a
cormel treatment and is recommended for cormels that can not be treated
with hot water.

For treating cormels, soak them in cool water for 2 days and dis-
card all floaters. After draining a few hours, soak the cormels for 2
hours in 3 ounces of Thimerosal per 100 gal. plus 2 ounces Triton X-100
or its equivalent. Plant within one or two days.

Panogen "15", a liquid containing 2.2% of the active ingredient, is
sold as a seed-treating fungicide. The same active ingredient at a concen-
tration of 0.6% is sold as a drench for greenhouse soil under the name of
Pano-drench "4". They are manufactured by Panogen, Inc., Ringwood, Ill.
and are available through some seed stores. Panogen 15 is recommended
for limited trial as a preplanting corm dip. For a 10 minute dip, use
3 1/2 pints in 100 gal. plus 2 oz. Triton X-100. For a one hour dip, use
2 pints. If Pano-drench "4" is used, about 4 times as much is needed or
6 1/2 quarts per 100 gallons for the 10 minute dip.

Standard Corm Dip Materials

1. N.I.Ceresan, 2 lb. plus 4 oz. Triton X-100 in 100 gallons water is recom-
mended mainly for dipping small corms. Soak corms in solution for 10 min-
utes and plant the same day in moist soil. Workers exposed to N.I.Ceresan
solution should wear shoulder-length rubber gloves to avoid gradual sys-
temic poisoning by absorption of the mercury.

2. Dowicide B, 4 lb. plus 3 oz. Triton X-100 in 100 gal. Soak corms 15
minutes before planting or when removed from storage. Reduce amount of
Dowicide B by one-fourth if temperature of water is over 80 F. after
standing in the sun. An old stock of Dowicide B can be used, even though
caked, if the amount is increased by one-fourth.

3. Captan 50W (Orthocide) 12 lb. in 100 gal. Keep stirred and soak corms
for 20 to 30 minutes. Captan 50W diluted with 3 parts of inert dust to
12 1/2% can be used as a dust applied immediately after cleaning the corms.
Captan dust has been more effective than Spergon.

Cautions: Corms or cormels treated with organic mercury compounds
such as N.I.Ceresan and Panogen should not be held in a closed room or ccn-
tainer where the vapors might accumulate and injure the corms. Panogen or
Thimerosal-treated cormels in a large cold storage room would not be in-
jured if held in trays with good ventilation. Workers' hands and arms
should be protected from contact with mercury-containing compounds and
washed off thoroughly if solutions are spilled on skin. Avoid breathing
dust. Prolonged exposure to Dowicide B will burn the skin but there is
no danger of systemic poisoning.

Corm treatment recommendations are the same as given last year in
Gulf Coast Station Mimeo Report 57-1 except that corms infected with Cur-




-4-


vularia or Stomatinia, or suspected of such infection, should be treated
before planting with N.I.Ceresan or Ceresan M as recommended on page 1 of
this report.

To control Fusarium on jumbo corms

1. Dust immediately after cleaning with 12 1/2% captain.
Or dip in captain 50W 12 lb.-l0 gal. for 20 to 30 minutes one week
before placing in cold storage.

2. After removing from cold storage, dip for 15 minutes in Dowicide B,
3 lb.-100 gal. If the weather is cool, use 4 lb. Add 3 oz. Triton
X-100 to each 100 gal. If roots have grown out of corms, soak the
corms for 20 minutes in captain 50W, 12 lb.-100 gal.

To control Fusarium on medium and small corms

Dip for 10 minutes in N.I.Ceresan 2 lb.-100 gal. plus 4 oz. Triton X-100
just before planting. If roots have grown out, dip for 20 minutes in 12
lb. captain 50W per 100 gal.

Corm treatment tests showed again this year that the N.I.Ceresan
treatments of 1 or 10 minutes are not as good on jumbo corms as treatments
with Dowicide B or captain, particularly in Picardy and Spotlight varieties.
N.I.Ceresan sometimes reduces the size of spikes one grade below that of
the other treatments. If the corms are scabby, N.I.Ceresan treatment is
liable to reduce the flower yields severely.

Double treatments (before and after storage) with Dowicide B, cap-
tan or N.I.Ceresan generally resulted in more spikes and corms than a
single treatment produced. Although the single treatments gave fewer
spikes, the spikes were larger and there were fewer culls. Thimerosal
treatment resulted in the highest yields of spikes. Captan treatment
tended to increase the grade of spikes over the other standard materials
in some tests. The experimental results also indicate thbt captain dip
and Dowicide B treatment are just as effective when corms are dipped a
week before storage as when they are dipped soon after cleaning. How-
ever, if corms are cleaned at digging time, they should be treated in cap-
tan dip the same day.

Soil Treatment for Disease Control

Stromatinia dry rot control is of extreme interest to those grow-
ers who have suffered poor production and short spikes as a result of
fall planting on infested land. Since the disease is carried on most
stocks of corms and cormels, even though chemically treated, it must be
assumed that most gladiolus fields have been contaminated. However, mois-
ture and other conditions in some soils are such that the fungus dies out
and the fields can be replanted without much trouble from Stomatinia. In
some of the well-drained soils on the Gulf Coast, however, the disease
builds up each year that gladiolus are planted. After 2 or 3 gladiolus
crops it is often impossible to grow a profitable crop when plantings are
made during October to late December unless the soil is treated.

Excellent crops were grown in heavily infested soil by treating the
soil with Vapam (VPM) or Crag Mylone about ten days before planting. DD and
EDB soil treatments were not effective against the disease. Vapam and My-
lone cost between $75 and $100 per acre for in-the-row treatment, and about
twice as much for broadcast treatment. The cost is partly justified by the




-4-


vularia or Stomatinia, or suspected of such infection, should be treated
before planting with N.I.Ceresan or Ceresan M as recommended on page 1 of
this report.

To control Fusarium on jumbo corms

1. Dust immediately after cleaning with 12 1/2% captain.
Or dip in captain 50W 12 lb.-l0 gal. for 20 to 30 minutes one week
before placing in cold storage.

2. After removing from cold storage, dip for 15 minutes in Dowicide B,
3 lb.-100 gal. If the weather is cool, use 4 lb. Add 3 oz. Triton
X-100 to each 100 gal. If roots have grown out of corms, soak the
corms for 20 minutes in captain 50W, 12 lb.-100 gal.

To control Fusarium on medium and small corms

Dip for 10 minutes in N.I.Ceresan 2 lb.-100 gal. plus 4 oz. Triton X-100
just before planting. If roots have grown out, dip for 20 minutes in 12
lb. captain 50W per 100 gal.

Corm treatment tests showed again this year that the N.I.Ceresan
treatments of 1 or 10 minutes are not as good on jumbo corms as treatments
with Dowicide B or captain, particularly in Picardy and Spotlight varieties.
N.I.Ceresan sometimes reduces the size of spikes one grade below that of
the other treatments. If the corms are scabby, N.I.Ceresan treatment is
liable to reduce the flower yields severely.

Double treatments (before and after storage) with Dowicide B, cap-
tan or N.I.Ceresan generally resulted in more spikes and corms than a
single treatment produced. Although the single treatments gave fewer
spikes, the spikes were larger and there were fewer culls. Thimerosal
treatment resulted in the highest yields of spikes. Captan treatment
tended to increase the grade of spikes over the other standard materials
in some tests. The experimental results also indicate thbt captain dip
and Dowicide B treatment are just as effective when corms are dipped a
week before storage as when they are dipped soon after cleaning. How-
ever, if corms are cleaned at digging time, they should be treated in cap-
tan dip the same day.

Soil Treatment for Disease Control

Stromatinia dry rot control is of extreme interest to those grow-
ers who have suffered poor production and short spikes as a result of
fall planting on infested land. Since the disease is carried on most
stocks of corms and cormels, even though chemically treated, it must be
assumed that most gladiolus fields have been contaminated. However, mois-
ture and other conditions in some soils are such that the fungus dies out
and the fields can be replanted without much trouble from Stomatinia. In
some of the well-drained soils on the Gulf Coast, however, the disease
builds up each year that gladiolus are planted. After 2 or 3 gladiolus
crops it is often impossible to grow a profitable crop when plantings are
made during October to late December unless the soil is treated.

Excellent crops were grown in heavily infested soil by treating the
soil with Vapam (VPM) or Crag Mylone about ten days before planting. DD and
EDB soil treatments were not effective against the disease. Vapam and My-
lone cost between $75 and $100 per acre for in-the-row treatment, and about
twice as much for broadcast treatment. The cost is partly justified by the




-4-


vularia or Stomatinia, or suspected of such infection, should be treated
before planting with N.I.Ceresan or Ceresan M as recommended on page 1 of
this report.

To control Fusarium on jumbo corms

1. Dust immediately after cleaning with 12 1/2% captain.
Or dip in captain 50W 12 lb.-l0 gal. for 20 to 30 minutes one week
before placing in cold storage.

2. After removing from cold storage, dip for 15 minutes in Dowicide B,
3 lb.-100 gal. If the weather is cool, use 4 lb. Add 3 oz. Triton
X-100 to each 100 gal. If roots have grown out of corms, soak the
corms for 20 minutes in captain 50W, 12 lb.-100 gal.

To control Fusarium on medium and small corms

Dip for 10 minutes in N.I.Ceresan 2 lb.-100 gal. plus 4 oz. Triton X-100
just before planting. If roots have grown out, dip for 20 minutes in 12
lb. captain 50W per 100 gal.

Corm treatment tests showed again this year that the N.I.Ceresan
treatments of 1 or 10 minutes are not as good on jumbo corms as treatments
with Dowicide B or captain, particularly in Picardy and Spotlight varieties.
N.I.Ceresan sometimes reduces the size of spikes one grade below that of
the other treatments. If the corms are scabby, N.I.Ceresan treatment is
liable to reduce the flower yields severely.

Double treatments (before and after storage) with Dowicide B, cap-
tan or N.I.Ceresan generally resulted in more spikes and corms than a
single treatment produced. Although the single treatments gave fewer
spikes, the spikes were larger and there were fewer culls. Thimerosal
treatment resulted in the highest yields of spikes. Captan treatment
tended to increase the grade of spikes over the other standard materials
in some tests. The experimental results also indicate thbt captain dip
and Dowicide B treatment are just as effective when corms are dipped a
week before storage as when they are dipped soon after cleaning. How-
ever, if corms are cleaned at digging time, they should be treated in cap-
tan dip the same day.

Soil Treatment for Disease Control

Stromatinia dry rot control is of extreme interest to those grow-
ers who have suffered poor production and short spikes as a result of
fall planting on infested land. Since the disease is carried on most
stocks of corms and cormels, even though chemically treated, it must be
assumed that most gladiolus fields have been contaminated. However, mois-
ture and other conditions in some soils are such that the fungus dies out
and the fields can be replanted without much trouble from Stomatinia. In
some of the well-drained soils on the Gulf Coast, however, the disease
builds up each year that gladiolus are planted. After 2 or 3 gladiolus
crops it is often impossible to grow a profitable crop when plantings are
made during October to late December unless the soil is treated.

Excellent crops were grown in heavily infested soil by treating the
soil with Vapam (VPM) or Crag Mylone about ten days before planting. DD and
EDB soil treatments were not effective against the disease. Vapam and My-
lone cost between $75 and $100 per acre for in-the-row treatment, and about
twice as much for broadcast treatment. The cost is partly justified by the





weed and nematode control obtained. A reduction of Fusarium disease may
also be obtained as indicated in tests carried out in pots.

After being tested for 3 years, Vapam and Crag Mylone can now be
recommended for controlling Stromatinia disease,but only in soil that is
known to be infested. When old gladiolus fields are to be planted during
the critical fall months, the soil should be tested to determine the de-
sirability of soil treatment. The test is easily made by each grower and
must be done a year in advance of planting in the questionable fields.
A representative sample of the field soil as well as soil from a nearby
uncontaminated field are placed in flats or boxes, taking care to avoid
any contamination of the "clean" soil with the gladiolus soil. Plant an
equal number of No. 6 corms or large cormels of any variety in each con-
tainer during the first week in November or no later than Nov.20. Use
hot-water treated stock if possible. Water the soil frequently to foster
disease development. The percentage of plants that survive for 6 to 8
weeks in the test soil compared to check soil indicates the amount of dis-
ease infestation. If plants in the gladiolus soil show leaf yellowing
and stunting along with sloughing of outer layer of roots, the soil carries
Stromatinia and should be treated, or planted before or after the critical
period.

Fusarium disease symptoms may be confused with those of Stromatinia
unless the following points are noted. Fusarium infections occurring in
the first few weeks cause the corms to rot and the outer layer of roots
does not slough off. Fusarium infection originating from the soil does
not usually show up until 8 to 10 weeks after planting small corms.

Methods of treating the soil. Whether Vapam gives satisfactory
results or not depends a great deal on the condition of the soil and on
sealing of the surface immediately after treatment. With Crag Mylone it
is also important to have the soil loose and moist but it is less critical
to get an immediate sealing. Crag Mylone (a powder) can be banded or mixed
with the soil, whereas Vapam (a liquid) is usually injected with shanks.
The soil should be worked up into seed-bed condition one or two weeks be-
fore treatment and kept moist.

For in-the-row treatment, the treated area should be 18 to 24 inches
wide for each row and special equipment should be developed to open and
close furrows without mixing the untreated soil into the bed. It is help-
ful, in this respect, to make the bed high when treated. The best way to
seal the soil surface is to apply about one-half inch of water overhead.
Also, a bed shaper is needed, something to compress and smooth the soil
on the sides as well as top of the bed.

Vapam (VPM) treatment. -- For each row use 3 shanks, 6 to 8 inches
apart, and inject liquid so that it will be about 5 or 6 inches below the
top of finished bed. The bed shaper is attached to the same tractor that
injects the Vapam. Each shank should deliver one pint of Vapam in travel-
ing 225 feet. Delivery rate is adjusted by varying size of orifice and pump
pressure. For broadcast or over-all treatment, apply as above in continuous
6 to 8 inch bands at a 5 or 6 inch depth and smooth the soil with light roll-
ers. If overhead irrigation is available, apply 1/2 inch water as soon as
possible. Plant 10 days after treatment. Wait longer if soil is heavy, wet
or cold. Avoid disturbing treated soil as long as practical after planting.





Crag Mylone treatment*, -- For in-the-row application, apply one
pound Crag Mylone 85W in a band 18 inches wide and 225 feet long. Mix
thoroughly to a depth of eight inches with tillers rototillerr or Seaman
tiller) and bed up slightly. Or broadcast 120 pounds per acre and mix with
tillers as above. Use bed shaper or rollers to firm and smooth soil sur-
face. Plant 14 days later, or wait a few days longer with clay or wet
soils or in cool weather.

At equivalent dosages by weight, Crag Mylone has usually given better
control of Fusarium and Stromatinia diseases than Vapam has,due at least
in part to the fact that the soil surface was not sealed quickly enough af-
ter the Vapam treatment.

In order to obtain maxima benefits from in-the-row treatments with
Crag Mylone and Vapam it will be necessary to modify certain cultural prac-
tices such as barring off the bed just before emergence of the shoots and
any unnecessary throwing of soil to the bed during the first month. The
original beds should be high enough to supply the soil needed to cover the
corms to a 4 or 5 inch depth. The use of EDB or DD will not be necessary
when Mylone or Vapam is used properly. Considerable weed control is ob-
tained, especially if the beds are not disturbed any more than necessary
after planting. Fertilizers may be side-dressed at planting. Subsequent
applications may be spread on the sides of beds and shallow sweeps used.

*Mylone may also be applied in one, two or three narrow bands as with fer-
tilizer distributors and covered to a 5 or 6 inch depth by hilling. Seal
surface with bed shaper. Although this method has not been included in the
gladiolus tests, it has worked well on other crops.









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