Physiological Disorders and Diseases of Ornamental Palms

1. Physiological Disorders and Diseases of Ornamental Palms Ed Skvarch St. Lucie County / University of Florida Commercial Horticulture Extension Agent

2. Physiological Disorders • Physiological disorders are those caused by various environmental factors, rather than biological agents

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

4. Environmental Disorders • A destructive physical occurrence to the plant.

5. Lightning Streaking, Bleeding, or sudden collapse of the crown

6. 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 !

7. 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.

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

9. Chilling Injury Some very tropical palms can be damaged by temperatures well above freezing

10. Foliar Salt Damage Foliar salt injury is fairly common along seashores during dry periods with strong onshore winds.

11. Excessive Water Take-Up • Due to greater water uptake • High rainfall, excessive rain • Irrigation • Visual symptoms should be sufficient to diagnose this disorder.

12. Power Line Decline Electromagnetic fields within 2 to 5 feet of a high voltage power line appear to cause injury to palm foliage

13. Wind Burn Leaves of wind susceptible species appear tattered, often with only leaflet midveins remaining

14. Sunburn Large necrotic areas are visible on the upper surfaces of leaves, usually in the center of leaves or leaflets

15. Water Stress Oldest leaves are usually the first to show symptoms

16. Planting Depth • Trunk Shriveling • Poor soil aeration • Drought • Will not affect structural strength of the palm trunk

17. Too Shallow ! Newly emerging adventitious roots arising from the base of the stem axis are exposed to dry air

18. Too Deep ! Note that at least one palm is dying from deep planting.

19. Just Right !!

20. Nutrient Deficiencies

21. Nitrogen (N) • Uniform light yellow-green discoloration of the older leaves. • As symptoms progress entire canopy will become uniformly light yellow. • New leaves emerge chlorotic. • Reduced growth rate.

22. Potassium (K) • 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.

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

24. Magnesium (Mg) • 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

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

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

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

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

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

30. Iron (Fe) • 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

31. Boron (B )Deficiency • 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.

32. Boron (B )Deficiency Hookleaf is an early and mild symptom of B deficiency.

33. Boron (B ) Deficiency Multiple unopened spear leaves caused by B deficiency

34. Boron (B )Deficiency Small crumpled new leaves are caused by severe B deficiency

35. Boron (B )Deficiency Blunt angular leaf tips are another common symptom, Effects leaves 4-5 months prior to leaf emergence

36. Boron (B )Deficiency Sharp bending in the stem

37. Diseases of Palms

38. Disease Interaction between the plant and a pathogen that disrupts the normal growth and appearance of the plant

39. University of Wisconsin

40. Ganoderma Butt Rot of Palms • 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

41. 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. • All palms are considered hosts of this fungus

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

43. Ganoderma Butt Rot of Palms • 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

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

45. New Disease of Queen Palms • 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.

46. New Disease of Queen Palms • 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

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