What's wrong with my palm tree? Diagnose common causes of leaf damage

Below are some common causes of damage to palm tree leaves and fronds plus tips on how to correct or prevent the damage from happening again. 

Fungal attack:

Above you can see dead patches in a Pritchardia frond.  These are caused by airborne pathogens such as mold and fungus landing on the fronds and rotting them.  Often, the tree is not as healthy as it should be.  Try a systemic fungicide and a foliar fungicide.  Copper, Physan 20, Subdue, and Captan 50 are all good ones.

 

Cold burn (frost burn):

The second cause of leaf damage is cold burn- also called frost burn.  This shows up as black or very dark brown leaflets as in the picture above.  This usually shows up 24-72 hours after a frost.  Once burned, the fronds need to be removed.  You can prevent frost damage by wrapping your palm in frost cloth or placing a space heater nearby (follow all instructions on the heater's manual to ensure safe use).

 

Drought:

When just the tips of your leaflets begin to turn brown, but the middle and inside portion of them are still green and healthy, this could be a sign of lack of water.  It always happens on the lower/older frond tips first and then makes its way to newer fronds if not addressed.  The two pictures above show one lower frond that got brown tips and then the next frond above it got the same brown tips, but none of the fronds are fully brown.  This is a good sign of drought.  I have seen this show up VERY quickly on Lipstick Palms which are aquatic palms that don't like drying out whatsoever.  In order to correct this problem, crank up your watering schedule or hook up supplemental irrigation to provide more water.

 

Natural leaf death

All palms have a primary growth point (or points) from which new fronds emerge.  As new fronds emerge, the oldest fronds die off as a natural life cycle.  If your palm has one fully dead leaf like in the two pictures above, and ALL other fronds appear fairly healthy, then it is likely shedding just that leaf on its own and this is perfectly normal.  Either allow the old frond to fall off on its own, or cut it carefully as close to the trunk as possible.

 

Sun burn:

Sun burn shows up as sections of newly-brown leaflets and often happens when a palm is moved into full sun too soon or if a nearby tree falls or is cut down and exposes a palm to direct sun light suddenly.  If you look at the picture above, only the parts of the leaves that are exposed to sun are brown and parts that were shaded or lower are still perfectly fine.  Notice that the brown leaf damage isn't at the tips only, nor is it dark or black in color like with frost burn, but instead only in large sections of the leaf where exposed to sun.  Sun burnt leaves should be cut off and the palm should be placed in more shade to prevent further damage.

 

Magnesium or Manganese defficiency:

Many granular fertilizers lack micronutrients like Manganese and Magnesium, OR they don't release these minerals quickly enough (like with 270 and 360 day release fertilizers used in South Florida).  This causes lime-green fronds with green streaks in the veins and midribs like in the picture below.  This often won't kill the palm, but it needs to be addressed.  Order some Magnesium Sulfate and Manganese Sulfate online and add it to your watering schedule (usually once every 4-6 weeks until corrected).

 

Spiraling Whitefly

A common pest in Florida is the Spiraling Whitefly.  It came up from Columbia years ago and is now in our state.  It shows up as round white colonies of bugs and webs on the adaxial surface of the leaf and can also cause "sooty mold" to develop underneath the palm.  It can only be treated with a powerful insecticide such as Safari.

 

Glaucous wax/tomentum:

This white covering on palm tree trunks and petioles is perfectly normal!  Some collectors reach out to us to ask what is wrong with their palm and we explain that some palms develop a white, waxy covering that is often called a glaucous coating or tomentum.  Such species were designed with this coating to help protect them from bacteria, fungus, insects, sun, algae, and other environmental factors.