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Group Title: ARC research report - Agricultural Research and Education Center - RH-82-1
Title: Aphelandra leaf crinkle
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Permanent Link: http://ufdc.ufl.edu/UF00066486/00001
 Material Information
Title: Aphelandra leaf crinkle Aphelandra stunt : a report from Florida
Series Title: ARC research report
Physical Description: 3 p. : ; 28 cm.
Language: English
Creator: Henley, Richard W
Agricultural Research Center (Apopka, Fla.)
Publisher: University of Florida, IFAS, Agricultural Research Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1982
 Subjects
Subject: Aphelandra -- Diseases and pests -- Florida   ( lcsh )
Leaves -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (p. 3).
Statement of Responsibility: R.W. Henley
General Note: Caption title.
Funding: ARC-A research report ;
 Record Information
Bibliographic ID: UF00066486
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 - 71213237

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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







APHELANDRA LEAF CRINKLE APHELANDRA STUNT
A REPORT FROM FLORIDA

R..W. Henley
IFAS, University of Florida ''
Agricultural Research Center Apopka
ARC-Research Report RH-82-1 r. U-i. i ..E

Aphelandra squarrosa with its highly variegated white and dark green -
leaves and yellow inflorescences has been a popular potted plant in the United
States for many years. At present, the most popular cultivars being grown in
Florida are Dania, followed by Apollo and Red Apollo. Apollo and Red Apollo
are more highly variegated than Dania and usually do not flower under normal
production environments.
Leaf shape is dramatically influenced by changes in light intensity. At
low light intensities 1000 foot-candles and less, developing leaves are
longer, narrower, and flatter than leaves which develop under 1500 foot-candles
and above. Under high light intensity new leaves are shorter and broader and
exhibit a puckered leaf surface. Increased light intensity also results in a
higher proportion of white tissue in the upper leaf surface and shorter internodes,
When Dania is grown under light intensities over approximately 800 foot-candles,
flowers are induced when plants are maintained at temperatures of 700F.
The malady known as Aphelandra leaf crinkle is distinctly:different from
the changes in leaf shape and texture caused by different light intensities. The
leaf crinkle problem which has been known to exist in Florida since at least 1973,
causes a pronounced stunting of terminal growth, reduced leaf size, an undesirable
downward reflexing, and twisting of the leaves. The level of leaf puckering is
only slightly-greater on plants with leaf crinkle than non-affected plants at a
given light intensity. Florida growers have observed symptoms of leaf crinkle are
expressed most rapidly at high light intensities. Once the leaf crinkle is
expressed within a plant there seems to be no reversal of the condition.
Recent reports from Texas A & M University (1,2) suggest that the leaf
crinkle problem does not appear to result from systemic fungi, bacteria, rickett-
sia-like or mycoplasma-like organisms. This conclusion was drawn after immersing
the root system of affected plants in a solution of 100-150 mm ppm of chlortetra-
cycline or tetracycline without any evidence of symptom remission. Electron
microscopic examination of healthy and non-healthy leaf tissue did not reveal any
virus-like particles. Leaf and stem sections from healthy and affected plants









plated on culture media did not indicate bacterial or fungal pathogens were
present.
The Texas researchers also evaluated the incidence of Aphelandra leaf
crinkle under three different light intensities approximately 60, 175, and
930 foot-candles, and temperatures of 68, 75, and 81F, respectively for the
three light intensities. The incidence of leaf crinkle increased with increased
light intensity and an increased temperature.
Preliminary unpublished results of an experiment conducted at the
Agricultural Research Center Apopka, indicate there Was no appreciable influence
of light quality on development of, or reversal of leaf crinkle in Aphelandra.
Plants were subjected to red, blue, green light produced by chambers covered with
acetate filters and sunlight which passed through a shaded greenhouse.
The propagation and early development growth stages of plants affected with
leaf crinkle were also evaluated at the Agricultural Research Center Apopka. In
both the 1973 experiment involving Dania and the 1981 test utilizing Apollo,
rooting and subsequent top growth of cutting was determined by the stock plant.
Plants propagated from plants exhibiting typical leaf crinkle symptoms rooted
poorly, developed very slowly, and retained the undesirable leaf crinkle symptoms
(Tables 1 and 2).


Table 1. Influence of crinkle leaf on root grade and shoot length of
Aphelandra squarrosa 'Dania' during propagation 1973.

Plant type Root grade* Shoot length (cm)**

Normal plant 4.8 34.8
Crinkle leaf plant 2.1 12.4

Root grade of terminal cuttings: 1 = no roots, 5 = good root system
(mean of 10 measurements).

Shoot developed from a single node cutting taken directly below the
cut for the terminal cutting (mean of 10 measurements).









Table 2. Influence of leaf crinkle on propagation and growth of Aphelandra
squarrosa 'Apollo' 1981.

Top growth after rooting

Root Shoot Shoot Pairs of
fresh wt* length fresh wt leaves
Plant type (g) (mm) (g)

Normal plant 13.2 14.9 5.3 2.4
Crinkle leaf plant 2.4 9.5 1.5 1.5
*
All values are the means of 10 measurements.


The author feels that the problem now called Aphelandra leaf.crinkle should
be more appropriately called Aphelandra stunt, due to the impact of the causal
factor on all aspects of plant development. The problem may be due to an
undetermined systemic factor. It seems unlikely that leaf crinkle could be
attributed entirely to physiological causes. The most likely reasons for the
malady are either an undetermined systemic agent or it may be expression of a
chimera with poor ornamental and growth qualities.
The cause of Aphelandra leaf crinkle is of academic interest, and knowing the
cause would permit more effective control or eradication measures. For the present
time, the best procedures for controlling leaf crinkle in commercial nurseries are
as follows: 1) purchase only high quality stock plants, 2) cull all stock plants
which display leaf crinkle before cuttings are taken, and 3) cull all finishing
plants which become stunted. Evaluation of stock under relatively high light
levels (just under that required to initiate flower buds) may help identify those
plants with leaf crinkle.


Literature Cited

1. Kamp, M., A. E. Nightingale, and R. W. Toler. 1981. Leaf crinkle disease
of Aphelandra in Texas. Plant Disease 65(8):687-688.

2. Kamp, M., R. W. Toler, and A. E. Nightingale. 1981. Aphelandra leaf crinkle
disease in Texas. Ornamentals South 3(2):6-7.




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