Other Palm Tree Problems
Certain species of palms, particularly date palms, will put out above ground roots that look like stubble around the base of the palm. Unless it’s a question of stability of the palm, air roots are not a problem. If stability is a problem, soil can be mounded up around the palm. Air roots will become active again.
Primary symptoms include foliage necrosis, erwinia and phytothphora (“bud rot”), and Manganese deficiency. Apply Manganese Sulfate and spray the leaves and bud with a copper hydroxide-based fungicide (Champ®, Kocide 101®, etc.) DO NOT trim off any dead leaves unless they are hanging down. Dead leaves protect the new growth from mechanical damage. Wait until there is significant new growth (mid-summer) before cutting off the old leaves.
Palms have only one growing point, called the “meristem” – the single shoot in the center of the crown. If the meristem turns brown or collapses, the palm has died. If it loses color or turns yellow, apply Manganese ASAP. The quickest way to do this is to spray Manganese Sulfate into the crown of the palm, and then put spikes around the root ball. If the symptom is caused from cold injury, drench the bud area with copper-containing fungicide* and apply Manganese spikes.
Fronds Stay Tight
Lack of Zinc (Zn) creates what is called “ladder leaf ” – where the fronds do not unfold properly. Applying Zinc Sulfate around the palm base for about three months will overcome this problem.
Symptoms on Coconut Palms include premature nut fall, or “shelling.” Nuts fall from the mid-crown section first, followed by younger very small nuts, and lastly by large mature nuts. Begin antibiotic treatment with oxytetramycin* as soon as symptoms are observed to extend the life of the palm. Under-planting with resistant varieties like Malayan Dwarf or Mapan is the real cure.
Pruning Dead Fronds
Dead fronds can be removed, so long as there is no green in them. If you are pruning several palms, sterilize the pruner between trees so you do not spread diseases. Magnesium-deficient palms where the fronds have yellowed can be removed so long as there is no green in them. Removing them when there is green on them can cause the magnesium deficiency to move up to the healthy fronds.
Also known as Pythium Blight, root rot is caused by too much water as a result of heavy soils or poor drainage – resulting in loss of older leaves and brown, soft roots (healthy roots are cream-colored and hard). Root rot is relatively easy to take care of by using Banrot® (Subdue® in California). It is a good idea to let palms go dry between watering.
With palms that are close to the ocean, there is a possibility of the build-up of salts, which can cause the ends of the fronds to turn brown, especially on the ocean side of the palm. Hosing salts out of crown once a week will help the problem.
Scale on Sago Palms
Horticultural oils can be used. Volk is one of the oils which suffocate the scale. (Do not use horticultural oils during the hot summer
season.) Insecticide soaps can also be used. They wash the waxes off the scale and the scale dies. All the leaves can also be cut off and taken away and burned. Ants actually move the scale, so controlling ants slows reinfestation.
Tips Turning Brown
This can occur for several reasons. Salt can be the culprit if close to the ocean and high winds occur. Brown tips will also happen if the palm has been very dry for some time, or subjected to very high temperatures. Extended soil saturation can also cause brown tips. If the cause is treated, brown tips are not serious and should disappear over time.
Wounds should be treated as soon as they are observed. Spray broad-spectrum fungicide/bacteria-stat into the wounds that contain Neutral Copper (sometimes referred to as Bordeaux* mixture). Such products, normally available at horticultural and nursery supply houses, is Champ® and Kocide 101®. Apply every two to three months for the first year, and every six months or so thereafter. Re-application after heavy rainfall is essential.
*Since pesticide labels are subject to frequent change, and vary from state to state, always read the label to insure the safety and legality of the intended use of that product. Legality and liability in the use of pesticides is the responsibility of the applicator and his/her associated company.