Group Title: AREC-A research report - Agricultural Research and Education Center-Apopka ; RH-85-8
Title: Flecking of Dracaena marginata
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Permanent Link: http://ufdc.ufl.edu/UF00065963/00001
 Material Information
Title: Flecking of Dracaena marginata
Series Title: AREC-A research report
Physical Description: 2 p. : ; 28 cm.
Language: English
Creator: Poole, R. T ( Richard Turk )
Conover, Charles Albert, 1934-
Agricultural Research and Education Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1985
 Subjects
Subject: Dracaena -- Diseases and pests -- Florida   ( lcsh )
Plants, Ornamental -- Diseases and pests -- Florida   ( lcsh )
Leaf spots -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 2).
Statement of Responsibility: R.T. Poole and C.A. Conover.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065963
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70927286

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Flecking of Dracaena marginata

R. T. Poole and C. A. Conover1
University of Florida, IFAS
Agricultural Research and Education Center Apopka
AREC-A Research Report RH-85-8


Leaf spots are common problems on Dracaena marginata and are caused by
numerous agents including the pathogen, Fusarium moniliforme, and fluoride. A
third disorder known as "flecking" has been apparent for several years.
Flecking can be confused with fusarium leaf spot which occurs initially on the
newest leaves. Fusarium causes irregularly shaped spots, tan to red-brown,
sometimes with a chlorotic border. Fluoride also causes tip necrosis, but the
damaged area is continuous, not spotty and it does not appear on the-newest
leaves. Flecking of Dracaena marginata appears as chlorotic spots near leaf
tips. They are usually small, 1-3 mm in diameter, circular, but sometimes
elongated, parallel to the leaf edge. There may be only a few light yellow
flecks, or they may be numerous, dark yellow and sometimes leaf edges are
necrotic. They are found on the newest leaves and frequently disappear as
leaves mature. Flecking is more prevalent during winter months, although it
also occurs at other times of the year.

Three studies were initiated to determine the cause of flecking. The
first experiment started October 12, 1981, examined effects of shade level and
irrigation frequencies (Table 1). Rooted cuttings were placed in 6 inch pots
containing a mix of Florida sedge peat and builder's sand (3:1 by volume).
Dolomite, 7 1bs/yd and Micromax, 1 Ib/yd were incorporated into the potting
medium. Osmocote, 19-6-12, 8.5 grams-pot, was surface applied. The degree of
flecking was evaluated January 28, 1982 (Table 1). Frequency of irrigation
did not affect flecking. Plants grown under 47% shade, about 4500 ft-c, had
slightly more flecking than plants grown under 80%
shade.

A similar experiment was started February 5, 1982, using the same shade
levels as Experiment 1, but storage of plants in coolers at 400F for various
times was used as the second variable to determine the influence of chilling
(Table 1). Flecking was evaluated February 26, 1982. Flecking was again
higher on plants receiving the higher light intensities, but cold storage
duration was not a factor.

The same shade levels were al o utilized fora ,simi lar experiment begun
June 25, 1982. The second factor involved fertilizeii 'vels (Table 1).
Although differences in flecking ere slight!, the ,higher light levels again
caused more flecking. Fertilizerjhad no effect o'6-amountof flecking
observed. .. o


Professor, Plant Physiology, and Professor and Center Director, respectively.
Agricultural Research and Education Center, 2807 Binion Road, Apopka, FL
32703.









These experiments do not really answer the question of "What causes
flecking on Dracaena marginata?" Over the years some people have thought the
problem was caused by a disease (none has ever been isolated from the spots),
while others have suggested watering, chilling or nutrition may be involved.
Data obtained in these experiments shows that flecking is affected by light
intensity, with plants in higher light more severely affected. Flecking is
transient in nature, sometimes occurring on most plants and at other times
present on only a few plants. In almost all cases, plants recover from
flecking and the tissue eventually turns the normal green color. In this
research, we could not find any relationship between irrigation or fertili-
zation level, nor storage duration at a chilling temperature. This does not
necessarily prove there is no relationship, but does indicate that the
relationship would have to be outside the parameters tested. If flecking is a
problem, lower light levels in the production area should be utilized.

Additional References


1. Chase, A. R., R. T. Poole and C. A. Conover.
a constant dilemma. Foliage Digest 3(5):5-7.

2. Osborne, L. S., A. R. Chase and R. W. Henley.
AREC-A Foliage Plant Research Note RH-1984-D.


1980. Fungus or fluoride -


1984. Dracaena marginata.


Table 1. Fleckingz of Dracaena marginata.


Experiment 1
Shade Flecking
Level,% 1/28/82


Experiment 2
Shade Flecking
Level,% 2/26/82


2.4
2.4
1.3


Irrigations/
week


Days
storage
400F


2.1
1.9
2.0
1.8
1.9


Experiment 3
Shade Flecking
Level,% 1/11/83

47 1.4
63 1.5
80 1.0



Ibs N/A-yr


1800
3600
5400


z 1 = none, 5 = severe.


-2-




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