Borers, Beetles and Bark Damage: Reading the Insect Signs on a Florida Tree

Homeowners call us about bugs more than almost anything else. Something is chewing the tree, there's sawdust at the base, the bark is coming off in sheets, and the question is always the same: what do I spray?

That is almost always the wrong question, and I want to explain why — because understanding it will save you money and, more importantly, might save the tree.

The Central Truth About Borers

Most wood-boring insects are secondary pests. They do not attack healthy, vigorous trees. They find trees that are already in trouble and finish them.

A healthy pine floods a beetle attack with resin and drowns it. A healthy hardwood walls off the wound. It takes a tree that's already weakened — by drought, root damage from a new driveway or pool, soil compaction, a lightning strike, storm damage, flooding, salt exposure, or a bad hurricane-cut pruning job — before borers can get established in numbers.

So when we find borers, the beetle is usually the symptom, not the disease. The real question is: what stressed this tree first? If you don't answer that, you're treating the wrong problem.

Learning to Read the Signs

Pitch tubes on pines

On slash pines and longleaf, look for popcorn-like blobs of resin on the bark — usually white to pinkish, sometimes the size of a dime, sometimes bigger. Those are pitch tubes: the tree's attempt to pitch the beetle out of its entry hole.

The location tells you who it is. Pitch tubes on the lower trunk, big and gummy, near the base, usually mean black turpentine beetle. Pitch tubes higher up the trunk and into the upper stem, smaller and drier, typically mean Ips engraver beetles.

Either way, the tree was already stressed. And on pines, once colonization is underway, it moves fast. Needles fade green to yellow to reddish-brown, often top-down, and by the time the crown is red the beetles have already left for the next tree.

Frass

Frass is a polite word for insect excrement mixed with chewed wood. It looks like fine sawdust. Look for it:

• Piled at the base of the trunk
• Packed into bark crevices
• Stuck in spider webs against the trunk (a great place to spot it)
• On the tops of branch unions

Fresh, pale, loose frass means active feeding right now. Old, dark, packed frass may be from an infestation that's already run its course.

Toothpicks sticking out of the bark

If you see what look like fine strands of compressed sawdust protruding from the bark like toothpicks, you're looking at ambrosia beetles — including the granulate ambrosia beetle, which is a serious pest of stressed and newly transplanted trees in Florida.

Ambrosia beetles are different in an important way: they don't eat the wood. They bore in, then farm a fungus they carry with them, and eat the fungus. That fungal symbiont is often what actually kills the tree, by plugging up its water-conducting tissue. Which means killing the beetle doesn't necessarily undo the damage — the fungus is already in the vascular system.

They hit stressed, flood-damaged, and newly planted trees especially hard.

Exit holes — and why the shape matters

When an adult borer emerges, it leaves a hole. The shape is a real diagnostic clue.

• Round exit holes — typical of many longhorned beetles and a lot of common wood borers.
• D-shaped exit holes — a flattened half-moon, characteristic of the metallic wood-boring beetles (the flatheaded borer group).

Look at the hole size, too. A cluster of tiny pinholes is a different insect than a scattering of pencil-width holes.

Gallery patterns under the bark

If bark is already lifting or sloughing off, peel a piece back and look at the wood underneath. The tunnels the larvae carved are called galleries, and they're a fingerprint.

Engraver beetles carve distinct, organized patterns — a central gallery with side branches running out from it. Flatheaded borers leave wide, meandering, flattened tunnels packed with frass. Ambrosia beetle galleries are narrow, clean, and often dark-stained from the fungus they're carrying.

If those galleries encircle the trunk, the tree has been girdled from the inside. That's terminal.

Woodpeckers as an early alarm

This one is free and most people ignore it. If woodpeckers suddenly start hammering a tree, they are finding something to eat in it. Sudden, concentrated woodpecker activity — especially patches where they've flaked the outer bark off in a shallow layer — is often the first outward sign of a borer population under the bark.

The birds knew before you did. Take the hint and go look at that tree.

The Palm Problem: Palmetto Weevil

Palms have their own villain, and it's a big one. The palmetto weevil is one of the largest weevils in North America, and it targets stressed, recently transplanted, and over-pruned palms. Canary Island date palms are especially prone.

Here's what matters for homeowners around New Smyrna Beach and Port Orange: the palmetto weevil is strongly attracted to the volatile compounds released by fresh cuts on a palm. Which means the "hurricane cut" — where somebody strips a palm down to a handful of upright fronds because it "looks cleaner" — is essentially an engraved invitation.

Over-pruning a palm does three bad things at once: it removes the fronds the palm needs to feed itself, it weakens the crown, and it broadcasts a chemical signal that says wounded palm here. By the time you notice the spear leaf collapsing or the crown flopping over, the bud is already destroyed, and a palm with a destroyed bud is dead. There is no coming back from it.

Prune palms when fronds are genuinely dead. Not on a calendar. Not for looks.

Why Spraying Usually Doesn't Work

The uncomfortable truth: by the time you can see the signs, the insects are inside the wood. A bark spray puts insecticide on the outside of a tree while the larvae are tunneling in the cambium and sapwood, protected by an inch of bark.

Preventive treatments have a role in specific situations — a high-value tree next to an active infestation, a known pest with a known life cycle, timed correctly. Systemic products can help against certain pests. But "spray the trunk of a tree that already has galleries in it and hope" is not a plan. It's spending money to feel like you did something.

And on pines with an established Ips infestation, honestly? The answer is usually removal, and it's usually urgent — because a colonized pine is a source population that will move to the next stressed pine on your street.

What Actually Helps

1. Fix the underlying stress. Water through drought. Stop compacting the root zone. Fix drainage. Mulch properly — a wide, thin ring, never piled against the trunk.
2. Stop wounding the tree. No topping. No hurricane cuts. No lion-tailing. No string trimmer hitting the base.
3. Remove infested wood promptly so the population doesn't spread to neighboring trees.
4. Don't leave a dead or dying tree standing where it can hit something. Borer-riddled wood loses strength quickly and comes apart in ways sound wood doesn't.
5. Get it looked at early, when the tree is stressed but not yet colonized — that's the window where intervention actually changes the outcome.

If you're seeing sawdust at the base, resin blobs on a pine, holes in the bark, or woodpeckers suddenly working a tree at your place in Edgewater or anywhere in Volusia County, call ArboristRX at (386) 444-5959. We'll read the signs, tell you what's underneath the bark, and give you a straight answer on whether the tree is worth saving or needs to come down before it fails.