This disease can be caused by various fungal pathogens, Phytophthora species and Thielaviopsis species, as well as by bacterial pathogens. While bud rot tends to occur after a tropical storm or periods of excessive rain, bacterial bud rot tends to occur after the bud has been damaged by cold weather.
Fusarium wilt is another palm tree fungus. Signs of wilt are fronds wilting, losing their green luster and, finally, dying. Once a tree is infected, there is no cure and the diseased tree may have to be removed.
Lethal yellowing is a disease first noticed in the Caribbean region of North America about 100 years ago. However, it was not until the 1950s and a devastating outbreak in Jamaica and the Florida Keys that the economic consequences of lethal yellowing were recognized and intensive research begun.
This disease is caused by the fungus Ganoderma zonatu which can infect many types of palm trees. The first symptom of infection is the withering and drooping of older fronds.
Leaf infections called “leafspots” are caused by a variety of fungi and some bacteria on many trees. Leaf spots can be circular to elongated, brown and possibly oily in appearance. The spots will vary in size and color depending on the plant, the organism involved and the stage of development.
If you found a lot of little circular, brown colored scales on your palm tree you are in trouble. It’s called “palm leaf scales”. You would never guess but palm leaf scales are actually a mature female small insect. They literally are just a small headless, legless bump and once the female has matured, it is unable to move from where it has planted itself.
They belong to a family of unarmored scale insects found in moist, warm climates. Mealybug females feed on plant sap, normally in roots or other crevices. They attach themselves to the plant and secrete a powdery wax layer (therefore the name mealybug) used for protection while they suck the plant juices. The males on the other hand, are short-lived as they do not feed at all as adults and only live to fertilize the females.
Cabbage palm caterpillars, found throughout Florida, target the cabbage palmetto almost exclusively. They rarely kill palm trees but the insects do destroy the trees’ blossoms. They are a nuisance to humans as well because they often enter homes looking for suitable places to pupate. Control by insecticides is possible under certain circumstances if carefully managed.
The borer is a large and quite ugly beetle whose larvae have a taste for the wood of the Washingtonia and Phoenix varieties. Borer grubs can live inside a palm trunk for up to nine years before exiting as beetles through quarter-sized holes.
The budworm is a beetle whose larvae feed on the flowers of a range of fan palms. The caterpillars are about an inch long and a pinky-green in color.
The Palmetto Weevil can be found throughout Florida, as far west as southern Texas and as far north as South Carolina. It is North America’s largest weevil. This pest has a taste primarily for the Cabbage Palm (sabal palmetto) although it will infest Saw Palmettos (serrenoa repens) and, occasionally, Canary Island Date Palms (phoenix canariensis), Washington Palms (washingtonia), Royal Palms (roystonea), and some coconut palms.
The Royal Palm Bug is an unusual insect. It feeds on only one plant, the royal palm, and the female lays one egg a day during the spring, a little like a chicken. The bugs rarely kill the host tree but the damage they do can be unsightly and they are difficult to control given the height of mature royal palms. These insects are the only North American members of the Thaumastocoridae family.
