| Material Information
||Maranta leaf necrosis
||ARC-Apopka research report
||2 p. : ; 28 cm.
||Chase, A. R ( Ann Renee )
Agricultural Research Center (Apopka, Fla.)
||University of Florida, IFAS, Agricultural Research Center
||Place of Publication:
||Marantaceae -- Diseases and pests -- Florida ( lcsh )
Leaves -- Diseases and pests -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
non-fiction ( marcgt )
||Statement of Responsibility:
| Record Information
||University of Florida
||All rights reserved by the source institution and holding location.
||oclc - 71125682
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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
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Copyright 2005, Board of Trustees, University
MARANTA LEAF NECROSIS
A. R. Chase
University of Florida, IFAS i153
ARC-Apopka Research Report RH-1980-1
F. ..S. L: of Fiorida
A previously unreported disease of Maranta has become a serious problem
for many growers in central Florida. Propagation of plants by tip cuttings
has resulted in heavy losses due to death of the terminal leaf. Greatest
losses occur to red Maranta, although green Maranta and many Calathea spp.
also are affected. This report is being published to alert growers to this
disease and to discuss the progress of current research into the cause of the
disease and control methods; it does not contain solutions to the problem.
DESCRIPTION OF THE SYMPTOMS
Symptoms of leaf necrosis and dieback center around the terminal leaf
usually while it is still rolled and often become apparent after plants have
been cut for propagation purposes. Although cuttings may have a healthy ap-
pearance at the time of removal they later develop necrotic or burned margins
along the base of the developing leaf. Symptoms include death of the side of
the leaf which was enclosed in the curl or the entire uncurled leaf. In the
worst expression of the problem, the curled leaf dies before it expands and
can be pulled out of the leaf sheath easily.
NATURE OF THE DISEASE
Indications are that this disease may be caused by a fungus which is
systemic in the plant. A brief survey of the Maranta industry in central
Florida has shown that some nurseries still have Marantas free of the disease.
The disease is apparently more severe when plants are exposed to a stress sit-
uation (anything in their culture which does not allow for optimum plant devel-
opment). Stresses created during rooting appear to trigger development of
symptoms in plants which are infected but not showing symptoms. This disease
can be spread to healthy plants by water carrying spores and by transfer of
infected cuttings from one nursery to another or from one stock bed to the
next. Until complete details of this disease have been described the following
control tactics are suggested.
NURSERIES.OR STOCK BEDS WITHOUT THE DISEASE
1. DO NOT bring any cuttings from a nursery suspected to have the disease
into any clean stock bed area. Cuttings from some foreign sources also
have this disease.
2. DO NOT take cuttings from an area showing symptoms and move to a healthy
stock area. Clean your cutting instruments with clorox or another dis-
infectant after cutting a bed.
3. Follow standard methods for disease avoidance such as use of new soil
and pots and keeping hose nozzles away from the ground.
NURSERIES-OR BEDS WITH THE DISEASE
1. DO NOT transfer any apparently disease-free plant material from these beds.
If any plants or parts of plants in a stock bed show these symptoms, most
of them probably have the disease.
2. Follow the best methods for growing Marantas. Do not place the plants
under any stress such as excess soil moisture, drought, or high temper-
atures, since these seem to affect severity of the disease. Keeping
nematodes under control also may aide in control of this disease.
GUIDELINES FOR MARANTA GROWTH
1. FERTILIZER: 900-1200 Ibs per acre per year of a 1-1-1 or 3-1-2 ratio
2. LIGHT: 1000-2000 foot-candles
3. TEMPERATURE: 60-90F
Exceeding these recommendations may result in stressing plants and
creating a situation in which this disease may develop.
Current research includes development of control tactics for Maranta
leaf necrosis, identification of the causal organism, and the
effect of environmental factors on disease development. Until this infor-
mation is available, growers should follow the suggestions outlined in this