Common Tree Problems in Florida

Ash Plant-bug:

ash plant ash plant ash plant

Tropidosteptes amoenus

Ash plantbug lays eggs in twigs and branches, then hatches causing infesta-tion to trees. Leaves become discolored first with white to yellow specs, then turning brown as leaves die. Early de-leafing of tree will occur and leaves will become deformed. Bugs feed on leaves.

Time of YearAffected TreesSymptomsRisk
MayAsh TreeBrown spots on leavesModerate
JulyNearyby trees and shrubsYellow/white specs on leaves
Deformed leaves
Early leaf dropping
Black spots underside of leaves
Red/black bugs in May

Asian Cycad Scale:

Aulacaspis yasumatsui

Originally found in Thailand and China, this pest has recently been introduced into Flori-da and infests Cycads and Palm species. Spread by wind from tree to tree, this pest will kill its host tree. White bugs that feed on leaves and attach themselves until death. They create a white protective film over themselves and build on top of themselves cre-ating the white scale. Death to host tree can occur in less than one year due to high in-festation of this pest and easy spreadability.

Time of YearAffected TreesSymptomsRisk
SpringCycadsWhitescales on leavesSevere
PalmsDead leavesFatal
King Sagos
Queen sagos
Cardboard palms


Aphis spiraecola, Aphis gossypii, Toxoptera aurantii, Toxoptera citricida

With over 400 different species, Aphids are the most common tree and shrub pest in Florida. Aphids feed off of sap from new growth areas of trees and shrubs. Aphids ex-crete honeydew as a waste product, which is a sticky substance that gets all over every-thing from sidewalks to vehicles, and structures.

Time of YearAffected TreesSymptomsRisk
SpringAll trees and shrubsSticky plantModerate – most trees and shrubs
FallCurly leaves
Discolored leavesHigh – pine & citrus trees
Black fungus

Apple Scab:

Venturia inaequalis

A fungal disease that causes direct loos of fruit and defoliation. Although not extremely harmful or fatal to trees, if not treated, defoliation will stunt tree growth and fruit yields. Leaf lesions are olive green to yellow in color. Fruit lesions are brownish and corky to the touch as fruit grows. Humidity and moisture can cause this fungus to spread rapid-ly.

Time of YearAffected TreesSymptomsRisk
Wet seasonsFruit treesLeaf spottingLow-Moderate
Fruit spotting


ash plant

hyridopteryx ephemeraeformis

A leaf feeding caterpillar that creates a silk “bag” out of silk and plant mate-rials. These pests grow up to one inch in length and carry around the bag on their backs until ready to lay eggs. Males fly off and infect surrounding trees, while females stay in same tree and cause further infestation and se-vere defoliation.

Time of YearAffected TreesSymptomsRisk
SpringEvergreens, coni-fers, box elderCocoons/bags hanging from branchesModerate
Summerjuniper, live oak, locust, maple, per-simmonDefoliation
pines, salt cedar, sumac, syc-amore, wild cherry, willow
ce-dar, cypress, elm, fruit and nut trees

Bacterial Leaf Scorch:

Xylella Fastidiosa

Leafhopper insects carry and transmit this bacterium throughout the host tree. The bac-teria cause a disruption to the trees watering ability by clogging vital watering channels. Leaf scorching cause’s severe damage to the host tree making it unsafe and causing eventual death. Easily spread

Time of YearAffected TreesSymptomsRisk
Spring timesweetgum, American elmBrowning of leavesHigh
Before summersycamore, mulberry, red maple, sugar mapleReddish or yellow bands separating live tissue from ne-crosis tissue.fatal
Oaks: bur, pin, scar-let, redGrowth decline
laurel, wa-ter, turkey, bluejackBranch death

Calico Scale:

ash plant

Eulecanium Cerasorum

A soft-scaled insect that has a black and white color in early life, and then loses their color in late life, turning dark brown. Insect invades trees with eggs in early Spring. Hatching begins in late Spring and by summer white Crawlers will appear and feed on leaves. The insect produces honeydew in the spring and causes leaves, bark, and branches to be sticky. Mold grows on the honeydew that is produced by the female insects. Crawlers will lay their eggs on the underside of leaves and then return to the woody parts of the tree.

Time of YearAffected TreesSymptomsRisk
Early Spring – lay eggsCrabappleHoneydew secretion (springtime)Moderate
Late Spring -hatchingDogwoodMold (summer)
Summer – infestationElmMold (summer)
Star magnoliaYellow leaves
FirethornBlack and white scale on leaves
Stone fruit trees
Boston ivy


ash plant

Iron deficiency that causes yellowing and scorching of leaves. Can affect tree in spots only, and not entire tree foliage. The yellowing of leaves is caused by a lack of chlorophyll and slows down the growth cycle of affected trees. Chlorophyll is responsible for the trees ability to pho-tosynthesize and turn sugars into energy. Trees will also produce bitter fruit that are smaller than normal and poor in quality. Iron deficiency can be caused by poor soil conditions such as lime content and high alkalinity. Cooler weather conditions, water saturation, and poor wind flow will intensify this condition and cause the tree to decline rapidly.

Time of YearAffected TreesSymptomsRisk
anyMapleYellow leavesHigh
PineSmall fruit
White OaksBitter tasting fruit
SweetgumStunted tree growth
River Birch
White Pine
Bald Cypress

Cottony Maple Scale:

ash plant ash plant ash plant

Pulvinaria innumerabilis

A flat, dark brown soft scaled insect that lays a white egg sac on branches in spring. Larvae hatch by early summer and feed on leaves and leave veins on the underside of leaves. Honey-dew is produced by females leaving a sticky residue on leaves, branches, and surrounding areas. Mold grows on honeydew. Crawlers return back to woody parts of tree but continue to infest tree. Trees can have yellowing leaves, early defoliation, and branch dieback – stunting growth and lowering defenses from other diseases.

Time of YearAffected TreesSymptomsRisk
SpringMapleWhite sacs on branchesModerate
ElmGray/black Mold
LindenYellowing leaves
HoneylocustBranch dieback
Osage Orange
Black locust

Diplodia Shoot Blight:

Diplodia sapinea

Time of YearAffected TreesSymptomsRisk
March-October (spores disperse)Most PinesShort new shootsHigh
Summer (disease is easily detectable)Australian PineBrown brittle needlesSevere
Scot PineLower branches turn brown
Ponderosa PineResin droplets
Mugo Pine
Red Pine

Dutch Elm Disease:

Ophiostoma Novo-Ulmi

A fungal infection that disrupts the water cycle within the tree. Water carrying veins are clogged and water is not able to reach the crown of the tree, causing wilting and death. This fungus can be spread by the Elm Bark Beetle or similar pests. Fungus can also be spread through tree grafting. Leaves turn yellow and curl, eventually turning brown and dying. Inner bark (Sapwood) will turn brown to tan in color. A cross-section of the branches should reveal when disease started in tree.

Time of YearAffected TreesSymptomsRisk
SpringAll Elm speciesYellow leavesHigh
July-September (growth season)Sections of dead leavesFatal
Dark branches and

Emerald Ash Borer:

Agrilus planipennis

Evasive Asian beetle that infests Ash trees by laying its larvae on the bark of the tree and hatch-lings tunnel and eat the tree from the inside-out. Sapwood is consumed and the water cycle of the tree is disrupted. Infested trees cannot get water up to the canopy, causing that portion of the tree to die, and possibly killing the entire tree. Difficult to detect early on as Ash trees do not give off strong indications of infestation. Emerald ash borers are a flat-head, metallic, green-iridescent beetle with a yellow-brownish abdomen. They create D-shaped holes in the trunk of Ash trees and are commonly hunted by woodpeckers. Hatching larvae are a white worm with a dark spine.

Time of YearAffected TreesSymptomsRisk
Summer – lay eggsAshGreen beetles in SummerHigh
May/June – hatchingD-shaped holes in trunkFatal
FallWoodpeckers pre-sent
New shoots from lower trunk
Leave discoloration

Elm Leafminer:

Fenusa ulmi

Insect that feeds on the leaves of most Elm trees. Its larvae form tunnels on the leaves causing blotchiness and discoloration to the leaves. In summer the larvae drop to the ground where they burrow in the ground in brown-papery cocoons and await spring to hatch. New hatchlings have white and light brown colored heads. Mining of leaves shows most in May – leaves will appear brownish with some holes.

Time of YearAffected TreesSymptomsRisk
May-June (larvae feed on leaves)Most ElmsBlotchy leavesLow-moderate
Summer (cocoons)Siberian ElmDiscolored leaves
Spring – hatchingRussian elmCocoons on ground
Slippery ElmHoles in leaves
American Elm
English Elm

European Elm Scale:

Gossyparia spuria

Insect with soft scales that produce honeydew as a byproduct, causing a sticky residue all over leaves, bark, branches, and the surrounding area. Mold will form over honey-dew. Eggs are laid at the end of spring and hatchlings come out in summer. Hatchlings feed on leaves, preferably the underside and then resort back to the woody parts of the tree in fall. Feeding stunts tree growth, causes dieback of branches, and leaves fall off sooner. Difficult to see as insect prefers high branches in tree.

Time of YearAffected TreesSymptomsRisk
Spring – matingAmerican ElmHoneydewLow
Summer – HatchingMost ElmsGray/black mold
HackberryThin crown
ZelkovaStunted growth
Yellow leaves
Branch dieback

Ficus Whitefly:

Singhiella simplex

Whiteflies start out as nymphs on the leaves of the Ficus tree and wonder until they lock onto a leaf and become immobile until adulthood. Whiteflies eat leaves, can cause wilting, yellowing leaves, stunt growth, cause early defoliation, and eventually kill the tree. Once an adult, the whitefly can travel to other trees and spread rapidly. Usually seem on the underside of leaves. They have 3 cycles per year. Swarm in white clouds of hundreds of flies to spread. Nymphs are transparent in color and difficult to detect early. Once swarming, the tree has been affected for several months. As they reach adulthood, the turn white with some yellow and red eyes.

Time of YearAffected TreesSymptomsRisk
All yearFicusSwarming white cloudsHigh
Weeping FigLeave yellowingFatal
Strangler FigWilting
Fiddler-leaf FigBranch dieback
Banana-leaf Fig
False Banyan
Cuban Laurel


Abnormal growths caused by insects that carry fungus, bacteria, mite, fly, midge, moth, wasp, or beetle larvae. There are over 2000 different types of gall producing insects, with 1500 being either wasps or gnats. The insects lay eggs in the plant tissue and the larvae feed off of the in-side of the gall growth. Once they reach the adult stage, they exit the gall through a small hole, leaving behind the growth and a hole that damages the plant. Galls are most commonly found in the stems or leaves of their host plants, but are not limited to trunks, flowers, fruit, or roots.

Time of YearAffected TreesSymptomsRisk
Spring – hatchingOaksAbnormal growthsmoderate
Summer – matingDaisyInsects emerging

Holly Leafminer:

Phytomyza ilicicola

A fly that lays its eggs in the leaf of the Holly tree and feeds on the leaves. Larvae feed between the upper and lower leaf surfaces leaving a tunnel in the leaves and damaging them. Females poke holes in the leaves, causing fluid to drip form the leaf. Leaves become distorted and disfigured by the holes and tunnels, and eventually stunt growth. Early defoliation can occur if tree is severely infested.

Time of YearAffected TreesSymptomsRisk
Early SpringMost type of HollyHoles in leavesModerate
American HollyTunnels/mines in leaves
English HollyDisfigured leaves
Dune HollyEarly defoliation
Yaupon Holly
Deciduous Holly
Japanese Winterberry

Honeylocust Plant Bug:

Diaphnocoris chlorionis

A light green to yellowish flying pest that feeds off of the new buds and leaves of the honey lo-cust plant. The pest injects a toxic saliva in to the leaves when they bite into the leave with their piercing-sucking mouthpart. This toxic saliva kills the surrounding leaf parts causing that area to turn yellow and die. Feeding can cause leaf rolling, disfigurement to the leaf, stunt growth, and/or Chlorosis. Infestation can weaken the tree and lead to a secondary pest infes-tation.

Time of YearAffected TreesSymptomsRisk
SpringHoney locustsDiscolored leavesLow
FallBlack locustsLeaf rolling
Thinning canopy
Stunted growth

Honeylocust Spider Mite:

Platytetranychus multidigituli

A mite that causes a bronzing of the Honey locust tree during the warm summer months. Trees that are stressed are most susceptible to this mite. Once mites hatch, they spread rapidly and feed on new growths, stunting the trees growth. Yellowing and whitish patches appear on the leaves of the tree and can turn brown and fall with heavy infestations. Mites are difficult to see with the naked eye, but can be found gathering on the underside of leaves.

Time of YearAffected TreesSymptomsRisk
SpringHoney locustTree bronzingModerate
SummerBlack locustYellow leaves
Early defoliation

Laurel Wilt:

Raffaelea lauricola

A fungus disease of the Red Bay, Avocado, and other trees that stops the water flow within the host tree and causes the leaves to wilt and die. The disease is spread through the ambrosia beetle and can easily kill the host tree. Laurel wilt is spreading rapidly throughout Florida. Small white tubes extent from the bark of infected trees and bark will begin to fall off host trees.

Time of YearAffected TreesSymptomsRisk
All yearRed BayWhite tubes ex-tending from barkSevere
AvocadoBark that falls offFatal
CamphorBark that falls off
PondspiceWiling tree
PondberryBeetle presence

Lecanium Scale:

Soft-shelled scaled egg sacks that are semi-circle shaped. These insects hatch from the sacks and feed on the foliage of the host tree. Honeydew is produced as a by-product of these pests and will make the branches and leaves sticky. A black mold will grow over the honeydew and leaves will fall early. Ants, bees, and wasps are attracted to the honeydew and are a sign that the tree is infested.

Time of YearAffected TreesSymptomsRisk
Spring (hatching)Most trees, especially:Brown nodules on branch of treeModerate
FallOaksHoneydew/sticky resi-due
MaplesBlack mold
BirchEarly defoliation
LindenStunted growth
ElmAnts, bees, or wasps

Magnolia Scale:

Neolecanium cornuparvum

An insect that removed fluids from its host tree by piercing holes in the plant. Females lay egg sacks on branches as white dome-shaped scales. Insect releases honeydew onto branches and leaves, which is sticky. Honeydew gets covered by a black mold on leaves and branches of host plant. Infestation leads to branch dieback, early defoliation of leaves, and eventually death to the plant.

Time of YearAffected TreesSymptomsRisk
SpringStar MagnoliaHoneydew on branches and leavesSevere
SummerSaucer MagnoliaBlack moldFatal
FallLily MagnoliaWhite dome-shaped scales
Cucumbertree Magno-liaGnats
Virginia CreeperAnts, bees, wasps on plant
Tulip TreeDead branches
Daphne Spp.
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