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Air Potato
A climbing vine with broad, heart-shaped leaves and potato-like aerial bulbils at the leaf joints. Compare the bulbil and leaf together.
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Forest diseases & disorders
Compare the host, affected plant part, and visible signs one specimen at a time.
Forest disorders: spot the clue
For each specimen, name the host, affected part, and visible pattern before choosing a disorder.
These names follow the published Florida FFA guide. The pictures show examples, not every life stage or symptom. Compare the host, damaged part, and visible evidence with your advisor’s current identification key.
45 of 45 disorders
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Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Ambrosia Beetles
Small beetles bore into wood and grow fungi in their tunnels. Look for tiny round entrance holes and fine pale boring dust; some species push out toothpick-like strands.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Annosum Root Rot
Root and butt decay may cause thinning crowns or groups of declining pines. Small shelf-like conks can occur near the base of a stump or tree; inspect the lower trunk and roots.
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Aphids
Small, soft-bodied insects often cluster on shoots or leaf undersides. Look for paired tubes near the rear of many aphids, sticky honeydew, and curled young growth.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Bagworm
A caterpillar carries a spindle-shaped silken bag covered with bits of leaves, needles, or twigs. The case hangs from foliage or branches.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Black Turpentine Beetle
Large pitch tubes low on the trunk can be a clue; compare location and gallery pattern.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Brown Spot Needle Blight
Brown spots and bands on pine needles can help identify this disease.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Butt-Rot of Hardwoods
Decay occurs in the lower trunk and roots. Look for softened wood, cavities, or fungal fruiting bodies at the base; several fungi cause this type of damage.
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Catalpa Worm
The catalpa sphinx caterpillar feeds on catalpa leaves. Mature larvae often have a dark stripe down the back, pale yellow sides, and a tail horn; color varies.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Cedar-Apple Rust
On juniper, rounded galls produce orange, gelatinous spore horns when wet. On the alternate apple host, look for orange leaf spots.
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Cicadas
Adults have large eyes and clear, strongly veined wings. Empty brown nymph skins may remain on bark; egg-laying can damage small twigs.
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Image sourceThis Photo was taken by Timothy A. Gonsalves. Feel free to use my photos, but please mention me as the author. I would much appreciate if you send me an email tagooty@yahoo.com or write on my talk page, for my information. Please contact me before commercial use.
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Cogon Grass
An invasive grass with a pale midrib that is often off center. Fluffy white seed heads and dense stands are useful clues; confirm the leaf and underground rhizomes.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Eastern Gall Rust
Look for rounded galls on pine twigs or branches; compare the host and gall with the official photo key.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Eastern Tent Caterpillar
A silken tent is commonly built where several branches meet; caterpillars travel to feed.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Fall Webworm
The web encloses leaves near the ends of hardwood branches.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Wood Borers
Inspect tunnels, exit holes, and sawdust-like frass in bark or wood. Longhorned beetles and their larvae are one example; this label covers several wood-boring insect groups.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Fusiform Rust
Pines may develop elongated, spindle-shaped galls on stems or branches; orange spores can appear.
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Gall Wasp
Abnormal growths form on oak leaves, twigs, or other plant parts around developing wasps. Gall shapes vary; compare the host and the particular gall, not just the presence of a bump.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Hardwood Leaf Spots
Look for distinct dead or discolored patches on broad leaves. Shape, margins, distribution, and host help distinguish causes; a leaf spot alone does not identify one pathogen.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Heart Rot
Fungal decay affects inner wood. Cavities, crumbly or discolored heartwood, and sometimes conks on the trunk can be clues; the outer tree may still look alive.
Image credit
Image sourceThis image was created by user weed lady (Sylvia ) at Mushroom Observer, a source for mycological images.You can contact this user here.CC BY-SA 3.0Resized and converted to WebP for study use.
Hypoxylon Canker
Bark sloughs off to expose a crust-like fungal layer on hardwoods. The exposed surface may change from tan to silvery gray and then dark or black.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Ips Engraver Beetles
Inspect the host and gallery pattern; Ips galleries often have a central chamber with branching galleries.
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Japanese Climbing Fern
A climbing fern with wiry twining fronds and finely divided leaflets. Look for the delicate, fern-like foliage spreading over other plants.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Juniper Blight
Young juniper shoots turn pale and then brown, often leaving dead branch tips among green foliage. Compare the transition between live and dead tissue.
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Kudzu
A vigorous climbing vine with three broad leaflets per leaf. Large leaves, hairy stems, and vines covering shrubs or trees are useful clues.
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Melaleuca
Invasive melaleuca has pale, peeling papery bark and narrow leaves with several lengthwise veins. White bottlebrush-like flower spikes may be present.
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Image sourceLoadmaster (David R. Tribble)
This image was made by Loadmaster (David R. Tribble).
Email the author: David R. Tribble
Also see my personal gallery at Google PhotosCC BY-SA 3.0Resized and converted to WebP for study use.
Mistletoe
A green parasitic plant grows directly from a host branch, often as a rounded clump. Broadleaf mistletoe has leathery leaves; look for its attachment to the tree.
Image credit
Image sourceUSDA Forest Service - Northeastern Area , USDA Forest Service, Bugwood.orgPublic domainResized and converted to WebP for study use.
Mites
Tiny plant-feeding mites can cause pale stippling or bronzing of foliage. Some produce fine webbing. Use magnification; leaf discoloration alone is not diagnostic.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Needle Cast of Pines
Affected needles become yellow or brown and are shed. Dark fungal fruiting structures on needles can help distinguish needle-cast fungi from other needle problems.
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Oak Leaf Blister
Raised, blister-like areas appear on oak leaves.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pine Coneworms
Caterpillars tunnel through cones or shoots. Look for resin, frass, webbing, and damaged cone scales or seeds; inspect the cone as well as the insect.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pine Needle Rust
Small yellow-orange, blister-like fungal structures appear on needles. Confirm that the structures are on the needles rather than on a woody stem gall.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pine Sawflies
Groups of caterpillar-like larvae feed on pine needles, sometimes leaving tufts of newer needles. Sawfly larvae generally have more abdominal prolegs than moth caterpillars.
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Pine Scale
Small, fixed scale coverings appear on needles. Pine needle scales often look like tiny white elongated spots; compare with fungal blisters and woolly insects.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pine Tip Moths
Young pine shoots wilt, brown, or die as larvae feed inside. Resin and fine webbing near damaged buds or shoot tips are helpful clues.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pine Webworm
Dense webbing holds together frass pellets and chewed needles on pine shoots. The clustered web and pellets are a useful field clue.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Pitch Canker
Look for resin flow, branch dieback, and cankers; compare the host and full symptom pattern.
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Psocids
Small barklice may gather on bark or beneath sheets of fine silk. They feed on surface material such as fungi and lichens and usually do not harm the tree.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Red Heart of Pine
A heartwood decay of living pines. Shelf-like conks can appear near branch stubs, while the inner wood develops pale pockets and decay.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Reproduction Weevil
Weevils damage young pine seedlings by feeding on bark near the root collar. Look for irregular patches of missing bark and a snout on the adult beetle.
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Slime Flux
A wet, often sour-smelling ooze may run from a wound on the trunk.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Southern Pine Beetle
Small pitch tubes and winding S-shaped galleries beneath bark are classic identification clues.
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Termite Damage
Look for galleries in wood and soil-like material or shelter tubes. Worker termites are pale and soft-bodied; damaged wood alone is not enough to distinguish termites from other borers.
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Image sourceSarah McCaffrey, Museum VictoriaCC BY 3.0 auResized and converted to WebP for study use.
Twig Girdler
A beetle chews a ring around a small twig, which may break off. The smooth external girdle and fallen twig distinguish it from ordinary storm breakage.
Image credit
Image sourceUSDA Forest Service — Insects and Diseases of Trees in the SouthPublic domain (US)Resized and converted to WebP for study use.
Variable Oakleaf Caterpillar
An oak-feeding caterpillar with variable coloration, often green with pale stripes and reddish markings. Use the head and body pattern as well as the oak host.