Transcript Disorders and Diseases of Ornamental Palms

Physiological Disorders and
Diseases of Ornamental Palms
Ed Skvarch St. Lucie County /
University of Florida Commercial
Horticulture Extension Agent
Physiological Disorders
Physiological
disorders
are those caused by
various environmental
factors, rather than
biological agents
Disorders Include
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Natural occurrences
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Lightning - Injury
Freeze damage
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Nutrient defincies
Nutrient toxicities
Planting depth
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No Pathogen involved
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Environmental Disorders
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A destructive physical
occurrence to the
plant.
Lightning
Streaking, Bleeding, or sudden collapse of the crown
Lightning
Visual symptoms are usually sufficient for diagnosis, No other disorder can cause a
perfectly healthy palm to collapse and die within a couple of days !
Freeze Damage
All species of palms are susceptible to cold temperature, but the
temperature at which injury will occur is dependent on the species and
the extent of its cold acclimation.
Freeze Damage
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Appear within a few
days
Hard freeze canopy
will dry out & smell
like hay
Can lead secondary
bud rots
Don’t give up
Chilling Injury
Some very tropical palms can be damaged by temperatures well above freezing
Foliar Salt Damage
Foliar salt injury is fairly common along seashores during dry periods with strong
onshore winds.
Excessive Water Take-Up
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Due to greater water
uptake
High rainfall,
excessive rain
Irrigation
Visual symptoms
should be sufficient to
diagnose this disorder.
Power Line Decline
Electromagnetic fields within 2 to 5 feet of a high voltage power line appear to
cause injury to palm foliage
Wind Burn
Leaves of wind susceptible species appear tattered, often with only
leaflet midveins remaining
Sunburn
Large necrotic areas are visible on the upper surfaces of leaves, usually
in the center of leaves or leaflets
Water Stress
Oldest leaves are usually the first to show symptoms
Planting Depth
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Trunk Shriveling
Poor soil aeration
Drought
Will not affect
structural strength of
the palm trunk
Too Shallow !
Newly emerging adventitious roots arising from the base of the stem axis are
exposed to dry air
Too Deep !
Note that at least one palm is dying from deep planting.
Just Right !!
Nutrient Deficiencies
Nitrogen (N)
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Uniform light yellowgreen discoloration of the
older leaves.
As symptoms progress
entire canopy will become
uniformly light yellow.
New leaves emerge
chlorotic.
Reduced growth rate.
Potassium (K)
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Potassium deficiency is
the most common
nutritional disorder of
palms !
Translucent yellow to
orange, black or necrotic
spots
Most severe on the
oldest leaves, and
towards the tips
Accentuated by high
nitrogen fertilization
within the root zone.
Potassium (K)
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Small canopies with
small chlorotic and
necrotic leaves.
Sharp tapering or
penciling – pointing
At this point palms
can often die if not
treated promptly.
Magnesium (Mg)
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Symptoms occur on the
oldest leaves
broad chlorotic bands
along the margins
central portion of the
leaves remaining
distinctly green
Most common on Canary
Island Date palms
Magnesium (Mg)
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Why?
Magnesium is readily
leached from sandy
and other soils having
little cation exchange
capacity.
Magnesium (Mg)
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This fan palm shows
Magnesium-deficient
older leaf
Note yellow bands
around the margins of
individual leaflets.
Manganese (Mn)
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Symptoms of Mn
deficiency occur on
the newest leaves
Often referred to as
“Frizzletop”
Caused primarily by
high pH soils
Manganese (Mn)
Manganese Deficiency
Potassium Deficiency
Potassium vs. Manganese Deficiency
Manganese (Mn)
Manganese-deficient Queen Palm showing frizzled new leaves,
but normal length older leaves.
Iron (Fe)
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New leaves emerge
yellow-green to nearly
white
Caused by poor soil
aeration, deep
planting, or high soil
pH
Green spots
superimposed on
chlorotic leaves
Boron (B )Deficiency
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Caused by B being
leached out of root zone
as a result of high rainfall
or excessive irrigation.
When leeching stops B
released from
decomposing organic
matter will again provide
adequate B for normal
palm growth in most
cases.
Boron (B )Deficiency
Hookleaf is an early and mild symptom of B deficiency.
Boron (B ) Deficiency
Multiple unopened spear leaves caused by B deficiency
Boron (B )Deficiency
Small crumpled new leaves are caused by severe B deficiency
Boron (B )Deficiency
Blunt angular leaf tips are another
common symptom,
Effects leaves 4-5 months prior to
leaf emergence
Boron (B )Deficiency
Sharp bending in the stem
Diseases of Palms
Disease
Interaction between the
plant and a pathogen
that disrupts the normal
growth and appearance
of the plant
University of
Wisconsin
Ganoderma Butt Rot of Palms
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The fungus is spread
primarily by the
spores produced in
the basidiocarp
The spores become
incorporated into the
soil, germinate and
the hyphae (fungal
threads) then grow
over the palm roots
Ganoderma Butt Rot of Palms
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Ganoderma butt rot is
caused by the fungus
Ganoderma zonatum.
This fungus degrades
or rots the lower 4-5
feet of the trunk.
All palms are
considered hosts of
this fungus
Ganoderma Butt Rot of Palms
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Symptoms may
include wilting (mild
to severe) or a
general decline
The disease is
confirmed by
observing the
basidiocarp (conk) on
the trunk
Ganoderma Butt Rot of Palms
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There are currently
no cultural or
chemical controls for
preventing the
disease
palm should be
removed as soon as
possible after the
conks appear on the
trunk
Leaf Spots
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Brown with a chlorotic
(yellow) halo
Leaf spots often
change in color and
size as the disease
progresses.
Overhead irrigation
spreads disease
New Disease of Queen Palms
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Oldist 2-3 leaves turn
brown but do not break.
Next 2-3 longest leaves
will turn varying shades
of yellow.
This will occur until entire
canopy is brown and
appears to have a has a
freeze –dried look to it.
New Disease of Queen Palms
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The time between initial
symptoms and palm
death is only months
One side of lef is green
the other side brown.
Brownish red stripe on
the petiole
Pathogen is unknown
Thank – You !!!
Acknowledgements to Timothy K. Broschat, Ph. D.
& Monica Elliot Ph.D. University of Florida / IFAS