Group Title: ARC-A research report - Agricultural Research and Education Center - RH-82-3
Title: Phytotoxicity of palms induced by foliar applications of copper
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00066484/00001
 Material Information
Title: Phytotoxicity of palms induced by foliar applications of copper
Series Title: ARC-A research report
Physical Description: 2 p. : ; 28 cm.
Language: English
Creator: Poole, R. T ( Richard Turk )
Conover, Charles Albert, 1934-
Agricultural Research Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1982
Subject: Plants -- Effect of copper on -- Florida   ( lcsh )
Palms -- Growth -- Florida   ( lcsh )
Copper -- Toxicity testing -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: R.T. Poole and C.A. Conover.
General Note: Caption title.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00066484
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 - 71213115

Table of Contents
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        Page 2
Full Text


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


HU I Ki;a i R. T. Poole and C. A. Conover
IFAS, University of Florida
agricultural Research Center-Apopka
ARC-A Research Report RH-82-3
i.F.A.S.-Uyv. of U
'- Co-pp@r-(Cduis an essential element for plant growth, but can be phytotoxic
at relatively low rates. In research conducted on aphelandra and schefflera,
plants receiving no supplemental Cu had normal green leaves when tissue Cu levels
were 10-15 ppm dry weight, but chlorosis appeared when Cu was applied and tissue
levels reached 20 ppm. When excess Cu was applied to Chlorella (an alga), there
was a reduction in total pigments and a blue shift of chlorophyll absorption with
an inhibition of photosynthesis. Copper can also inhibit uncoupled photosynthesis
electron transport, and precipitate iron as iron phosphate. Since Cu is often
used to control plant disease, we decided to test several compounds and rates
commonly used, as we observed damage on palms in several commercial nurseries.

Experiments were established September 18, 1980, and August 24, 1981, with
identical treatments and similar test conditions to evaluate the effect of
several Cu compounds on Chrysalidocarpus lutescens (areca palm) (Expt. 1) and
Chamaedorea seifrizii (reed palm) (Expt. 2). In both experiments, air temperature
was approximately 850F (300C) at time of spray application and skies were clear.
Variables included spraying with water, Cu Sequestrene 1 and 2 g/l; Kocide, a
fungicide, at 1 g/l (1 lb/100 gal) and 2 g/l; and with Copper-Count-N, a fungicide,
at 5 ml/l (1/2 gal/100 gal) and 10 ml/l. Manufacturer recommended rates are:
Kocide 1.5 lbs/100 gal, Copper-Count-N 1 gal/100 gal, and Cu Sequestrene 1 lb/100
gal. Approximately 6 months prior to experiment initiation, well-rooted, healthy
3 leaf palm seedlings were potted into 15 cm diameter pots containing Florida sedge
peat, cypress shavings, and pine bark (2:1:1 by volume). Plants were grown in a
shadehouse where they received 3000 foot-candles maximum natural illumination,
temperatures from 650 minimum to 1000F maximum, overhead irrigation twice weekly
with no overhead watering during spray applications, and a relative humidity of
90 + 10%.

In Expt. 1, Osmocote 14-14-14 (N-P205-K20) was surface applied at a rate of
4 g/pot/3 mo, equivalent to 1200 Ibs N/A/yr, and the potting medium amended with
5 lbs dolomite/yd3. In the second experiment, Osmocote 19-6-12 (N-P205-K20) was
applied at 3.3 g/pot/3 mo, equivalent to 1200 lbs N/A/yr, with no dolomite added.

Phytotoxicity grades were established based on severity of necrotic spotting
observed on frond leaflets with 1 = no damage; 3 = moderate damage with 2 to 3
fronds having several necrotic spots 1 cm or larger; and 5 = severe damage with 5
or more fronds having necrotic spots 1-2 cm or larger (most plants had a total of
5 or 6 fronds). Phytotoxicity ratings were recorded after 1 week for both
experiments, and again after 2 months in Expt. 1,

All Cu sprays produced damage on both palm species tested (Table 1), with
Copper-Count-N the most damaging compound. Higher application levels were

generally more damaging than lower levels, although results were inconsistent
with Copper-Count-N. Rates used in these experiments were similar or bracketed
those recommended by manufacturers, thus one could expect damage on palms at
recommended levels if these compounds were used under similar environmental
conditions. Although foliar sprays of iron, manganese, and zinc have proven
beneficial for palm growth and have improved foliage color, Cu at levels used
in this experiment was detrimental, For optimum palm appearance, use materials
with minimum or no Cu content when applying micronutrients, and if fungicides
are needed, avoid using those containing Cu,

Table 1. Phytotoxicity grade of palms.
Areca palm (Expt. 1) Reed palm (Expt. 2)
Treatments 1 wk 2 mos 1 wk
1. Control 1.8 1.2 1.0
2. Cu SeqY, 1 lb/100 gal
(1 g/1) 2.4 1.4 1.8
3. Cu Seq, 2 lb/100 gal
(2 g/1) 2.6 1.8 3.2
4. Kocide, 1 lb/100 gal
(1 g/l) 2.2 2.8 2.2
5. Kocide, 2 lb/100 gal
(2 g/l) 2.6 3.4 2.2
6. Cu-Ct-Nx,l lb/100 gal
(5 ml/1) 3.0 3.4 4.4
7. Cu-Ct-N, 2 lb/100 gal
(10 ml/1) 2.6 4.0 3.8

zl = no damage; 3 =
necrotic spots > 1
necrotic spots > 1

moderate damage with 2 to 3 fronds with several
cm; 5 = severe damage with 5 or more fronds with

YCu Seq = Copper Sequestrene.
XCu-Ct-N = Copper-Count-N.

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