First Aid for Your Trees, Servicing the Greater Tampa Bay Area

Common Palm Tree Diseases & Insect Pests

One of the benefits of living in Florida is the beautiful palm trees that bring an added tropical flare and sense of relaxation to our landscapes. Palm trees have special tree care needs, such as routine fertilization to help ensure they stay healthy and strong. Routine tree care is a preventative measure to help trees fight off the many tree diseases and insect pest infestations they are susceptible to. Therefore, it is highly recommended to have a tree service plan with a local arborist, failure to take preventative measures could result in the loss of your palm trees. Many palm tree diseases are not correctable but, are preventable.

Although many palm tree diseases are not correctable, some are. So, what do you do if you do not have a routine palm tree service plan but, your trees are starting to look a little under the weather? Below we have listed a few of the more common palm tree diseases and insect pests that plague Tampa’s beautiful palm trees. If any of your palm trees are showing symptoms for some of these common tree issues it is best to contact your local arborist right away.

Palm Tree Diseases

black infected flower on a palm with lethal yellowing
By USDA Forest Service [CC BY 3.0 ], via Wikimedia Commons
Lethal Yellowing Disease

Lethal Yellowing is the most prevalent palm tree disease in Florida, specifically in the southern part of the state. This disease is systemic, caused by phytoplasma (an unculturable cell of wall-less bacterium) found only in the phloem tissue. When the disease is not attached to a host plant or insect it will not survive. It is transferred by a planthopper insect that feeds on the palms vascular system. The phytoplasma is moved to each palm during its feeding cycle. If you think your palm tree is infected some symptoms to look for include:

  • Fruit falling from the palm tree prematurely.
  • You may notice the ends of coconuts, where the stem is, will become discolored turning a brownish-black and the area may appear wet.
  • During your palm tree’s blooming season, you will see the signs of disease in the flowers. All, or some of, the flowers will begin to turn black and die prematurely.
  • The fronds will turn an unsightly yellow, hence the name lethal yellowing, before turning brown and completely dying.

What are your treatment options should your palm tree become ill with lethal yellowing? The first step to treating a palm tree with lethal yellowing disease, is to test the tree and confirm that it is in fact lethal yellowing disease. There is another palm tree disease called the Texas Phoenix Palm Decline (TPPD) that is equally as ramped in Florida, where the symptoms are identical. Despite the correlation in symptoms, the lethal yellowing and TPPD are genetically different; therefore, your trees need to be properly tested to differentiate between the two diseases before treatments can be administered. Treatment for both the lethal yellowing and TPPD is dependent on the progression of symptoms. Both palm tree diseases are treated with antibiotics; however, this is not a complete cure. These diseases are chronic, and the antibiotics work to prevent the diseases from developing or progressing further. With Texas Phoenix Palm Decline (TPPD) the antibiotics will only work if the spear leaf, the central growth point of the palm tree, has not died.

white film marking the leaves of a palm tree
Coconut (Cocos nucifera): Spiraling whitefly (Aleurodicus dispersus)by Scot Nelson is licensed under CC Mark 1.0

Spiraling White fly

The Spiraling White Fly, first reported in Florida back in 2009, is an insect pest that uses the palm tree as its host plant and while it feeds on the palm’s fronds it will infect it with a nasty disease. The fly itself has a life cycle of 30 days, in this time the female will lay its eggs on the underside of the palm leaves in a spiral pattern and then cover the leaf in a white waxy film. The Whitefly must be able to complete a lifecycle from egg to adult on its host plant. Some species can’t support the full development but can still be used for feeding and for the female to lay eggs. The level of feeding it can do and the development of other stages will determine if management of the plant is required. Infestation of this pest usually doesn’t kill the host plant, but it can slow its growth. The spiraling white fly causes stress to its host plant by removing water and nutrients which allows for the growth of black sooty mold. This pest excretes a substance called honeydew, which is sticky and once dry the mold forms in thick layers. Not only is this detrimental to the tree it’s a nuisance in the area because of the sticky mess it makes falling onto all the surfaces surrounding the tree. If any of the honeydew or black sooty mold fall into nearby pools the contamination is bad for the water and filtration system.

Palm Tree Insect Pests

small brown scale insect on a palm leaf
By gailhampshire from Cradley, Malvern, U.K (Scale insect) [CC BY 2.0 ], via Wikimedia Commons
Palm Leaf Scale

What are those little brown circles on your palm trees’ fronds? It’s actual an insect pest called palm leaf scale. This unusual insect pest is a very small female that has no head or legs. Once it decides to implant itself on a palm tree it will not move again. This insect pest usually prefers the newer fronds on your palm tree. However, no matter where these pests have decided to attach themselves, they can cause severe damage to the palm tree.

The Palm Leaf Scale feeds on the palm tree through a long appendage inserted into the palm frond, or leaf. This appendage is used like a straw, sucking the liquid and nutrients from the palm frond. Having just one of these little creatures on your palm tree is not the end of the world; however, if the palm tree scale multiplies on the palm, the palm tree will die without proper treatment.

Palmetto Weevil

The Palmetto Weevil is a beetle that is generally mostly black, however some Palmetto Weevils are all red, with a black pattern. This insect pest is most commonly associated with the cabbage palm tree. It is an active flier until it finds its host palm, then it hides between the leaf bases to conserve water in its body. These beetles prefer palm trees that are already stress or dying because they give off an odor. The ailing tree’s odor attracts the Palmetto Weevil to it and once it has landed it will send out a signal, inviting its buddies to join it.

Proper pruning, fertilization, and irrigation of palm trees, especially Cabbage Palms, is essential to the prevention of Palmetto Weevil infestation. If a palm tree should be completely taken over by these insect pests, the damage is often beyond correction and the crown of the tree will break and fall to the ground. If the insect pest infestation gets to this point, then the palm tree will need to be properly removed and disposed of, to prevent the spread of infestation.

all black insect similar to a beetle
By Jorfer [Public domain], from Wikimedia Commons

red insect with black pattern on flowers of palm tree
Matt edmonds at English Wikipedia [CC BY-SA 3.0 or GFDL], from Wikimedia Commons

If any of the palm trees in your landscape are presenting with one or more of the above-mentioned symptoms you should contact your local arborist, right away. Palm trees can be very expensive to replace and are a landscape investment. If you haven’t already, speak with a your local arborist or a tree service provider in your area about setting up a quarterly palm tree maintenance plan.

With over 30 years of experience, the arborists here at Tree Medics in Tampa, finds that prevention with a routine palm tree maintenance plan, is the most efficient and cost-effective method for handling, or better yet preventing, these insect pests and diseases from affecting your palm trees and landscape. If you are located in Hillsborough County or the Greater Tampa Bay area, give our palm tree expert a call today at (813) 407-9974

By USDA Forest Service [CC BY 3.0 ], via Wikimedia Commons

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