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Group Title: AREC-H research report - Agricultural Research and Education Center-Homestead ; SB-82-1
Title: Fungicides for anthracnose control on mangoes in Florida
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Permanent Link: http://ufdc.ufl.edu/UF00067845/00001
 Material Information
Title: Fungicides for anthracnose control on mangoes in Florida
Series Title: Homestead AREC research report
Physical Description: 3 leaves : ; 28 cm.
Language: English
Creator: McMillan, Robert Thomas, 1934-
Agricultural Research and Education Center, Homestead
Publisher: University of Florida, Agricultural Research and Education Center
Place of Publication: Homestead Fla
Publication Date: 1982
 Subjects
Subject: Mango -- Diseases and pests -- Control -- Florida   ( lcsh )
Fungicides -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaf 2).
Statement of Responsibility: R.T. McMillan Jr
General Note: "January 19, 1982."
 Record Information
Bibliographic ID: UF00067845
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 72536136

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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




) 0


Homestead AREC Research Report SB82-1 January 19, 1982

Fungicides for Anthracnose Control on Mangos in Florida

R. T. McMillan, Jr.
Associate Plant Pathologist
University of Florida, IFAS
Agricultural Research and Education Center
Homestead, Florida

i" : ":: .... ---- INTRODUCTION

The major mango (Mangifera indica L.) diseases cause considerable annual losses to
Florida growers. With the strict grade standards in effect,control of diseases
causing fruit blemishes and decay has become very important. Most mango diseases
are adequately controlled by various forms of fungicides. Unfortunately, disease
control is never flawless because complete coverage is a practical impossibility and
because the rapid growth rate of leaves and fruit exposes unsprayed tissue to in-
fection.

For most of the commercial mango cultivars, anthracnose, caused by Colletotrichum
gloeosporioides Penz., is probably the most difficult production problem facing the
Florida mango grower.

Mango anthracnose causes blossom blight, leaf spot, fruit russeting or tear stain-
ing, and fruit rot. Disease damage is closely dependent upon humidity. The spring
rains and/or heavy dews during the critical period for infection greatly increases
the disease. (Lynch and Mustard 1956 and Ruehle and Ledin 1960)

At present, copper and benomyl are the only fungicides approved by the Environmental
Protection Agency and the Food and Drug'Administration for anthracnose control.
Early experiments conducted by Ruehle and Ledin (1960) showed that weekly appli-
cations of zineb, maneb or captain during blooming followed by monthly applications
of copper provided adequate control. Conover (1965) found that Dithane M45 (maneb),
Daconil or ferbam when used as in-the-bloom sprays provided equal control.
McMillan (1973) reported that benomyl, when applied at bloom and post bloom, pro-
vided outstanding control of anthracnose. Since then, a new promising fungicide
has been developed which provides control of anthracnose. Results of experiments
with these materials are described herein.

MATERIALS AND METHODS

The commercial mango (Mangifera indica L.) cv. 'Keitt' was used in all experiments
because of its susceptibility to anthracnose. The new fungicides evaluated are
listed in Table 1. The fungicides were applied as dilute aqueous spray with a
MIloyer grove sprayer at 400 gallons per acre. Bloom sprays, first used when panicles
were about 2 inches in length, were applied weekly until all fruits had set and
monthly thereafter until 30 days before harvest. A randomized block design was
used with four replicates. Data on anthracnose control were collected. Fruits
were harvested when most trees carried several ripening fruit. Anthracnose control
was evaluated by rating disease incidence on the fruit as:disease free, mild (tear-
stain too slight to affect grade), and severe (active rot or severe tearstain suf-
ficient to reduce grade).

Commercial grove production practices were followed throughout the experiments.










RESULTS AND DISCUSSION

All fungicide treatments significantly reduced the incidence of anthracnose compared
to the control (Table 1). Benomyl and Topsin led to an average of 89.3 and 88.8 per
cent disease free fruit whereas yields of such fruit with maneb plus copper averaged
only 72.7 per cent and 48.2 per cent with copper. Dithane M45 used throughout did
not differ from benomyl and Topsin alone or in combination with Dithane M45. There
were no disease free fruit from the non-sprayed controls. Disease control from the
maneb-copper treatment was similar to that obtained by Conover (1965).

The application of Benlate and Topsin significantly increased marketable yield
(Table 1). Ninety per cent of the fruit from the benomyl plots was marketable com-
pared to 80 per cent from maneb-copper and copper and 17 per cent from the control
plots.

The 90 per cent marketable fruit in the Benlate and Topsin treatments showed them
to be outstanding fungicides. However, until Topsin and Dithane M45 receive EPA
approval, recommendations by the IFAS Extension Service remain the same as Fig. 1.


LITERATURE CITED

1. Conover, Robert A. 1965. Results of recent experiments on control of mango
anthracnose. Fla. State Hort. Soc. 78:364-369.

2. Lynch, John S. and Margaret J. Mustard. 1956. Mangos in Florida. Department
of Agriculture, Tallahassee, Florida, Bul. 20.

3. McMillan, R. T., Jr. 1973. Control of anthracnose and powdery mildew of mango
with systemic and nonsystemic fungicides. Tropical Agriculture 50(3):245-248.

4. Ruehle, G. D. and R. B. Ledin. 1960. Mango growing in Florida. Fla. Agr.
Exp. Sta. Bul. 174.











Fig. 1. General Spray Schedule for Control


of Anthracnose


Time of Application

1. As first panicles are approximately
2 inches.
2. One week after No. 1.
3. One week after No. 2 and repeat
at 7-day intervals as long as
there is open bloom.
4. At fruit set and not longer than
7 days after the last benomyl
application.
5. Three to four weeks after No. 4
until 14 days of harvest with
benomyl and up till harvest with
copper.


Fungicide

Benomyl 1 to 2 lbs. per acre


7t 17 II 1f
I T I1 II 11I


?W 11


Benomyl 1 to 2 lbs. per acre or
Micronized copper 2 to 4 lbs.
per 100 gallons of water.
Benomyl 1 to 2 lbs. per acre or
Micronized copper 2 to 4 Ibs.
per 100 gallons of water.


Table 1. Control of anthracnose of 'Keitt' mango 1980-81.


Per cent of fruit1
Fungicide treatment and spray concentration Clean Severe Marketable

Benlate 1.5 lbs/A2,3,4 89.3a 5.6a 94.la
Topsin 1.5 lbs/A2,3,4 88.8a 5.4a 93.7a
Benlate + 1.5 lbs/A2',3, 88.5a 5.7a 93.4a
Dithane M45 1.5 lbs/100 gal23
Topsin + 1.5 lbs/A 2 3, 87.6a 5.5a 93.0a
Dithane M45 1.5 lbs/100 gal
Dithane 145 1.5 lbs/100 gal2'3'5 86.8a 5.9a 92.0a
Dithane M45 + 1.5 lbs/100 gal2'3 72.7b 18.6b 85.2b
Copper (TBCS) 3 lbs/100 gal214
Copper 3 lbs/100 gal2,3,' 48.2c 19.Tb 80.Ob
Control O.Od 82.5c 17.5c



In any column means followed by the same letter do not differ significantly.
2Surfactant Nu-Film-17 at 4 ozs per 100 gallons.
3Bloom-fungicide applied every 7 days from time 2 inch panicle appears.
Post bloom-fungicide applied every 3 to 4 weeks from fruit sets.
5Post bloom-fungicide applied every 7 days from fruit set.


i




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