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Group Title: Research report - Agricultural Research and Education Center - RH-1982-24
Title: Suggestions for chemical control of Areca palm leaf spot
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Permanent Link: http://ufdc.ufl.edu/UF00066502/00001
 Material Information
Title: Suggestions for chemical control of Areca palm leaf spot
Series Title: Research report
Physical Description: 2 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Poole, R. T ( Richard Turk )
Agricultural Research Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1982
 Subjects
Subject: Areca -- Diseases and pests -- Control -- Florida   ( lcsh )
Palms -- Diseases and pests -- Control -- Florida   ( lcsh )
Leaf spots -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: A.R. Chase and R.T. Poole.
General Note: Caption title.
Funding: ARC-A research report ;
 Record Information
Bibliographic ID: UF00066502
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 - 71225998

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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




-- "J


SUGGESTIONS FOR CHEMICAL CONTROL OF ARECA PALM LEAF SPOT.

A. R. Chase and R. T. Poole
University of Florida, IFAS
Agricultural Research Center-Apopka
Research Report RH-1982-24

Controlling Areca palm leaf spot is a continuing problem for many
growers producing plants under shadehouse conditions or with overhead
irrigations. There are several fungi which cause leaf spot of palms,
including Bipolaris setariae, Exserohilum rostratum, and the less common
Phaeotrichoconis crotalariae. Although these are distinctly different
pathogens, the symptoms they cause and the control measures required are
essentially the same. Two efficacy trials are reported here using various
chemicals available for use on some foliage plants.

The first test was performed in a greenhouse on Chrysalidocarpus
lutescens planted in 6" pots. The plants were free of symptoms initially.
The chemicals used included: Ornalin 50WP (1.5 and 3.0 lb/100 gal rates)
and Daconil 2787 4.17 F (1.5 lb/100 gal rate). Other treatments included
a noninoculated control and an inoculated control which received no chemical
sprays. The chemicals were applied once prior to inoculating the appropriate
plants with spores of Bipolaris setariae and then six additional times on
weekly intervals. Plants were watered from overhead to insure good disease
development. The degree of disease severity was rated twice, first after
four chemical applications and second after all seven applications. Daconil
provided excellent control at the 1.5 lb/100 gal rate and Ornalin provided
equivalent control at the 3.0 lb/100 gal rate (Table 1). Neither chemical
damaged the plants in any obvious manner.

The second efficacy trial was performed under shadehouse conditions on
plants similar to those used in the first test. In this case the plants were
naturally infected with Exserohilum rostratum during the course of the trial.
The following chemicals and suitable controls were included: Kocide 101 (1.5
lb/100 gal), Manzate 200 (1.5 lb/100 gal), Zineb 75WP (1.5 lb/100 gal) and
Carbamate (ferbam, 1.5 lb/100 gal). Sprays were made on a weekly basis between
6-15-82 and 9-28-82 for a total of 16 applications. Disease severity was rated
on 10-6-82 (Table 2). All fungicides provided good control of this leaf spot
and caused no symptoms of phytotoxicity with the exception of the Kocide. In
this case all the plants treated with Kocide showed symptoms of copper toxicity
similar to those seen on plants sprayed with excessive copper (necrotic areas
in new leaves and severe chlorosis and necrosis of older leaves).

These two tests indicate that many of the fungicides used to control palm
leaf spot at present can be effective even under shadehouse and overhead
irrigation conditions. The key to control of these leaf spot diseases is
eliminating or minimizing overhead watering and rainfall and thus the opportunity
for pathogen development. Use of a conscientious preventative fungicide program
is also quite effective and could include such fungicides as Daconil, Ornalin,
Carbamate, Manzate and Zineb. Since other fungicides are available with similar


Use of trade names does not imply a recommendation of those products over others
with similar active ingredients.






activities, these can be utilized as well. Removal of older leaves with
severe leaf spots is also recommended since they serve as a source of
inoculum for new infection.

As a final note, current studies at the ARC-Apopka have revealed that
microelement toxicity (especially copper) can also cause symptoms of leaf
spot which are indistinguishable from disease symptoms. Always be sure
that it is a disease you are treating and not nutritional imbalance or
phytotoxicity.


Table 1. Control of Areca palm leaf spot caused by Bipolaris setariae.

Treatment Inoculation Disease rating:9-16-82 10-7-82

Water water 1.0 ab 1.0 a
Water spores 2.8 d 2.8 d
Ornalin
(1.5 lb) spores 1.8 bc 1.9 bc
Ornalin
(3.0 lb) spores 1.4 ab 1.6 ab
Daconil
(1.5 lb) spores 1.2 ab 1.2 a

aA total of 12 plants was used for each treatment with 1 = no disease
to 4 = severe disease.
bNumbers in the same column followed by the same letter were not
statistically significant of 5% level using Duncan's multiple range test.


Table 2. Control of Areca palm leaf spot caused by Exserohilum rostratum
in a shadehouse.

Treatment Disease rating Quality rating

Water 2.4 bc 3.6 bc
Carbamate
(1.5 lb) 1.3 a 3.5 bc
Kocide (1.5 lb) 1.8 a 3.0 ab
Manzate
(1.5 Ib) 1.2 a 3.5 bc
Zineb
(1.5 lb) 1.4 a 4.0 c
aDisease rating was made for 5 plants per treatment with 1 = no disease and
4 = severe disease.
bQuality rating was made on a scale of 1 = poor, to 4 = good plant- salable.
CNumbers in the same column followed by the same letter were not statistically
different using Duncan's multiple range test at 5%.


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