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 Historic note
 Introduction
 Cultural suggestions
 Directions for using streptomy...














Group Title: Sub-Tropical Experiment Station - mimeographed report ; no. 54-2
Title: Suggestions for using streptomycin sprays to control bacterial spot in tomato and pepper plantbeds
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Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00067800/00001
 Material Information
Title: Suggestions for using streptomycin sprays to control bacterial spot in tomato and pepper plantbeds
Series Title: Mimeographed report
Physical Description: 3 leaves : ; 28 cm.
Language: English
Creator: Conover, Robert A
Sub-Tropical Experiment Station
Publisher: University of Florida, Sub-Tropical Experiment Station
Place of Publication: Homestead Fla
Publication Date: 1954
 Subjects
Subject: Tomatoes -- Diseases and pests -- Control -- Florida   ( lcsh )
Peppers -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Robert A. Conover.
General Note: "June, 1954."
Funding: Mimeographed report (Sub-Tropical Experiment Station) ;
 Record Information
Bibliographic ID: UF00067800
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71826380

Table of Contents
    Historic note
        Copyright
    Introduction
        Page 1
    Cultural suggestions
        Page 2
    Directions for using streptomycin
        Page 2
        Page 3
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




Mimeographed Report TIo. 54-2 June 95 954
University of Florida
SUB-TROPICAL EXPERIMENT STATION
Homestead, Florida

'SUGGESTIONS FOR USING STREPTOMYCIN SPRAYS
TO CONTROL BACTERIAL SPOT IN TOMATO AND PEPPER PLANTBEDS
by
Robert A. Conover


Bacterial spot has been a serious and largely uncontrolled disease of tomatoes and
peppers in some sections of Florida for many years. Along the Lower Erst Coast the
disease is especially destructive during the fall rainy season. Seedlings in plant-
beds prepared for the fall and winter crops are often rendered unfit for use as
transplants as a result of the disease. Others, less severely damaged, are used and
the disease thus introduced to the field may cause considerable loss when prolonged
or driving rain occurs. If bacterial spot is to be controlled in the field, it
seems apparent that control should start in the plantbed, and that effective control
there should result in much less damage in the field.

In 1952 experiments were started at the Sub-Tropical Experiment Station to determine
whether certain antibiotics would control bacterial spot in plantbeds. In these
early experiments, streptomycin sprays controlled the disease. In 1953 in a large
experiment in a commercial planting Agri-mycin*, an agricultural formulation con-
taining streptomycin and Terramycin*, gave outstanding control of bacterial spot on
tomato seedlings. Beds sprayed with Agri-mycin (at a concentration of 200 ppm.
(parts per million) streptomycin and 20 ppm. Terramycin) had an average of 74%
disease-free plants whereas adjacent untreated beds had only 11%. Only 5% of the
plants in treated beds were judged unfit for use as transplants whereas 73% of those
in unsprayed beds were considered worthless. Observations suggested that these re-
sults would have been even better had all beds been sprayed with Agri-mycin.
Similar results have been obtained with pepper seedlings although fewer experiments
have been made and on a much smaller scale.

The use of streptomycin presents problems somewhat different than those usually en-
countered in plant disease control. Perhaps the most important of these is the
possibility that resistant strains of the bacterial spot organism may develop follow-
ing continued use of streptomycin. Chas. Pfizer & Co., Inc., manufacturer of Agri-
mycin, has shown that the development in the laboratory of streptomycin-resistant
strains is inhibited or greatly delayed if Terramycin is mixed with the streptomycin.
It is for this reason that their product contains both streptomycin and Terramycin.
At the present time it is not possible to evaluate the importance of this problem in
the field in South Florida, or to judge the relative merits of sprays containing
streptomycin alone, or in combination with Terramycin. The possibility of developing
a streptomycin-resistant strain would increase in proportion to the length of time
streptomycin was used. Thus streptomycin alone might be used for 4 or 5 applications
in the plantbed without too great a risk. On the other hand, continuous use for 8
to 10 weeks, as might be done in the field, would be much more likely to result in
the development of a streptomycin-resistant type of the bacterial spot organism.

The grower should understand that these experiments are preliminary and the results
obtained, while encouraging, do not provide the final answer to bacterial spot con-
trol. Actually, several more years experience will be required before the treatment
can be fully evaluated. The grower should understand that streptomycin sprays are
expensive and that they constitute an extra treatment above that usually applied to
a planted. However, it is believed that the benefits obtained from planted treat-
ments will be reflected in less loss from bacterial spot in the field. Should this
prove to be the case, streptomycin may be a most economical plantbed treatment.

Trade mark, Chas. Pfizer & Co., Inc.




-2-


CULTURAL SUGGESTIONS

The following suggestions, based on factors wThich influence the spread and severity
of bacterial spot, will aid in controlling bacterial spot in plantbeds:

1. Locate plantbeds on new land (also helps to avoid wilt, rootknot and weeds),
or at least on land not planted to tomatoes or peppers for several years.

2. Elevate bed above the level of surrounding soil and slope beds for
immediate drainage; avoid areas subject to standing water for even brief
intervals.

3. Do not disturb seedlings while wet; above all, do not pull wet plants.

4. Do not get leaves wet when pulled plants are dipped in water or starter
solutions.

5. Set plants as soon as pulled; avoid leaving plants in boxes overnight.

6. If bacterial spot occurs in localized areas in plantbeds, start pulling
plants in unaffected areas and work toward affected areas.


DIRECTIONS FOR USING STREPTOMYCIN

It is felt that the program outlined below will control bacterial spot in plantbeds
in most circumstances. However, more experience is needed before one can say
exactly how much streptomycin is required, when it should be applied, and how much
benefit will result from its use. The following suggestions, provided for those
growers who wish to experiment with streptomycin sprays, are the best that can be
made at present:

1. Use sprays containing 200 ppm. (parts per million) streptomycin.* The
amount required to provide this concentration should be provided by the
manufacturer of the formulation used.

2. Make the first application when the first true leaves are about one-half
to three-fourths expanded. If diseased plants are nearby, make the first
application as soon as seedlings have emerged. Subsequent applications
should be made every four or five days.

3. Make the first application before bacterial spot is seen in the bed. If
this cannot be done, the writer believes that best results will be ob-
tained if the first spray contains 400 ppm. streptomycin.

4. Reapply streptomycin in the event of a hard rain within 18 hours of a
treatment, especially if bacterial spot is established in the plantbed or
is nearby.

5. Apply sufficient sprey to thoroughly wet the plants.




Your County Agent, or the nearest Experiment Station, can advise you
where streptomycin formulations may be obtained.




-2-


CULTURAL SUGGESTIONS

The following suggestions, based on factors wThich influence the spread and severity
of bacterial spot, will aid in controlling bacterial spot in plantbeds:

1. Locate plantbeds on new land (also helps to avoid wilt, rootknot and weeds),
or at least on land not planted to tomatoes or peppers for several years.

2. Elevate bed above the level of surrounding soil and slope beds for
immediate drainage; avoid areas subject to standing water for even brief
intervals.

3. Do not disturb seedlings while wet; above all, do not pull wet plants.

4. Do not get leaves wet when pulled plants are dipped in water or starter
solutions.

5. Set plants as soon as pulled; avoid leaving plants in boxes overnight.

6. If bacterial spot occurs in localized areas in plantbeds, start pulling
plants in unaffected areas and work toward affected areas.


DIRECTIONS FOR USING STREPTOMYCIN

It is felt that the program outlined below will control bacterial spot in plantbeds
in most circumstances. However, more experience is needed before one can say
exactly how much streptomycin is required, when it should be applied, and how much
benefit will result from its use. The following suggestions, provided for those
growers who wish to experiment with streptomycin sprays, are the best that can be
made at present:

1. Use sprays containing 200 ppm. (parts per million) streptomycin.* The
amount required to provide this concentration should be provided by the
manufacturer of the formulation used.

2. Make the first application when the first true leaves are about one-half
to three-fourths expanded. If diseased plants are nearby, make the first
application as soon as seedlings have emerged. Subsequent applications
should be made every four or five days.

3. Make the first application before bacterial spot is seen in the bed. If
this cannot be done, the writer believes that best results will be ob-
tained if the first spray contains 400 ppm. streptomycin.

4. Reapply streptomycin in the event of a hard rain within 18 hours of a
treatment, especially if bacterial spot is established in the plantbed or
is nearby.

5. Apply sufficient sprey to thoroughly wet the plants.




Your County Agent, or the nearest Experiment Station, can advise you
where streptomycin formulations may be obtained.







- 3 -


6. Streptomycin was not mixed with other materials in experiments reported
herein. Laboratory studies indicate that streptomycin is compatible
with some fungicides, insecticides, and soluble fertilizers used in
sprays, but is incompatible with others. Until these results can be
verified in the field, it would probably be wise not to mix other materials
with streptomycin.

7. Maintain the same fertilizer, disease and insect control program usually
practiced. Streptomycin is not intended to control fungus diseases or
insects.

Since the use of streptomycin sprays for bacterial spot control is still
experimental, it is desirable that information be obtained during the fall of
1954 which will permit a thorough evaluation of the treatment. This can be done
if growers experimenting with streptomycin will keep the following records:

1. Date when seedlings emerge.

2. Dates of applications of streptomycin.

3. Concentration of streptomycin used, and gallons applied each application.

4. Size of plants (in number of leaves) at each application.

5. Number of hours elapsed between each application and the next shower.

6. Daily rainfall records.

7. Materials mixed with streptomycin, if any.

8. Fungicides, insecticides, and nutritional sprays used and dates of
applications.

When the seedlings are large enough to set in the field, it would be appreciated
if the grower would give the writer, or another plant pathologist, these records a
and an opportunity to inspect the plantbeds and evaluate the treatment.




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