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 Physiological disorders are those caused by various environmental factors, rather than biological agents

Disorders Include Natural occurrences Natural occurrences Lightning - Injury Lightning - Injury Freeze damage Freeze damage Nutrient defincies Nutrient defincies Nutrient toxicities Nutrient toxicities Planting depth Planting depth No Pathogen involved No Pathogen involved

Environmental Disorders A destructive physical occurrence to the plant. 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.

Appear within a few days Appear within a few days Hard freeze canopy will dry out & smell like hay Hard freeze canopy will dry out & smell like hay Can lead secondary bud rots Can lead secondary bud rots Don’t give up Don’t give up Freeze Damage

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 Due to greater water uptake Due to greater water uptake High rainfall, excessive rain High rainfall, excessive rain Irrigation Irrigation Visual symptoms should be sufficient to diagnose this disorder. 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 Trunk Shriveling Trunk Shriveling Poor soil aeration Poor soil aeration Drought Drought Will not affect structural strength of the palm trunk 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) Uniform light yellow- green discoloration of the older leaves. Uniform light yellow- green discoloration of the older leaves. As symptoms progress entire canopy will become uniformly light yellow. As symptoms progress entire canopy will become uniformly light yellow. New leaves emerge chlorotic. New leaves emerge chlorotic. Reduced growth rate. Reduced growth rate.

Potassium (K) Potassium deficiency is the most common nutritional disorder of palms ! Potassium deficiency is the most common nutritional disorder of palms ! Translucent yellow to orange, black or necrotic spots Translucent yellow to orange, black or necrotic spots Most severe on the oldest leaves, and towards the tips Most severe on the oldest leaves, and towards the tips Accentuated by high nitrogen fertilization within the root zone. Accentuated by high nitrogen fertilization within the root zone.

Small canopies with small chlorotic and necrotic leaves. Small canopies with small chlorotic and necrotic leaves. Sharp tapering or penciling – pointing Sharp tapering or penciling – pointing At this point palms can often die if not treated promptly. At this point palms can often die if not treated promptly. Potassium (K)

Symptoms occur on the oldest leaves Symptoms occur on the oldest leaves broad chlorotic bands along the margins broad chlorotic bands along the margins central portion of the leaves remaining distinctly green central portion of the leaves remaining distinctly green Most common on Canary Island Date palms Most common on Canary Island Date palms Magnesium (Mg)

Why? Why? Magnesium is readily leached from sandy and other soils having little cation exchange capacity. Magnesium is readily leached from sandy and other soils having little cation exchange capacity. Magnesium (Mg)

This fan palm shows Magnesium-deficient older leaf This fan palm shows Magnesium-deficient older leaf Note yellow bands around the margins of individual leaflets. Note yellow bands around the margins of individual leaflets. Magnesium (Mg)

Manganese (Mn) Symptoms of Mn deficiency occur on the newest leaves Symptoms of Mn deficiency occur on the newest leaves Often referred to as “Frizzletop” Often referred to as “Frizzletop” Caused primarily by high pH soils Caused primarily by high pH soils

Manganese (Mn) Potassium Deficiency Manganese Deficiency Potassium vs. Manganese Deficiency

Manganese-deficient Queen Palm showing frizzled new leaves, but normal length older leaves. Manganese (Mn)

Iron (Fe) New leaves emerge yellow-green to nearly white New leaves emerge yellow-green to nearly white Caused by poor soil aeration, deep planting, or high soil pH Caused by poor soil aeration, deep planting, or high soil pH Green spots superimposed on chlorotic leaves Green spots superimposed on chlorotic leaves

Boron (B )Deficiency Caused by B being leached out of root zone as a result of high rainfall or excessive irrigation. 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. 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

The fungus is spread primarily by the spores produced in the basidiocarp 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 The spores become incorporated into the soil, germinate and the hyphae (fungal threads) then grow over the palm roots Ganoderma Butt Rot of Palms

Ganoderma butt rot is caused by the fungus Ganoderma zonatum. This fungus degrades or rots the lower 4-5 feet of the trunk. 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 All palms are considered hosts of this fungus

Symptoms may include wilting (mild to severe) or a general decline Symptoms may include wilting (mild to severe) or a general decline The disease is confirmed by observing the basidiocarp (conk) on the trunk The disease is confirmed by observing the basidiocarp (conk) on the trunk Ganoderma Butt Rot of Palms

There are currently no cultural or chemical controls for preventing the disease 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 palm should be removed as soon as possible after the conks appear on the trunk Ganoderma Butt Rot of Palms

Leaf Spots Brown with a chlorotic (yellow) halo Brown with a chlorotic (yellow) halo Leaf spots often change in color and size as the disease progresses. Leaf spots often change in color and size as the disease progresses. Overhead irrigation spreads disease Overhead irrigation spreads disease

New Disease of Queen Palms Oldist 2-3 leaves turn brown but do not break. Oldist 2-3 leaves turn brown but do not break. Next 2-3 longest leaves will turn varying shades of yellow. 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. This will occur until entire canopy is brown and appears to have a has a freeze –dried look to it.

The time between initial symptoms and palm death is only months The time between initial symptoms and palm death is only months One side of lef is green the other side brown. One side of lef is green the other side brown. Brownish red stripe on the petiole Brownish red stripe on the petiole Pathogen is unknown Pathogen is unknown New Disease of Queen Palms

Thank – You !!! Acknowledgements to Timothy K. Broschat, Ph. D. & Monica Elliot Ph.D. University of Florida / IFAS