Palm pest

Ambrosia Beetles

KillerSeriousManageableMostly cosmetic

Tiny wood-boring beetles that attack palms and trees already under stress. Finding them usually means the host was in trouble before they arrived.

Holes in trunkFrassSawdust tubes

Palms it affects: Any stressed palm, Coconut palm, Royal palm, Queen palm, Canary Island date palm, Foxtail palm

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Ambrosia beetle damage on a royal palm: a dark streak bleeding down the trunk.

Affects: Any stressed palm, Coconut palm, Royal palm, Queen palm and more
When it shows: Spring flight peaks about February through May, and after hurricanes, drought, cold and transplanting.
What we do first: Find the stress that drew them in.

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What you see

Signs in the field

Thin tubes of packed sawdust sticking out of the trunk like toothpicks
Fine, flour-like boring dust in bark crevices, leaf bases and on the ground below
Clusters of pinhead-sized holes, often weeping sap or fermented fluid
Narrow, dark-stained tunnels when an attacked trunk is cut
A thinning, paler canopy and wilting as the attack builds

Often confused with

Palmetto weevil Silky cane weevil Thielaviopsis trunk rot Ganoderma butt rotLightning damageHarmless sap or resin flow

From the field · 1 of 3

Staining and small holes at the base of a palm trunk: ambrosia beetle.

The detail

What else to know

A sign of stress

Ambrosia beetles are secondary pests. Females fly to hosts that give off the scent of decline: drought, flooding, cold injury, lightning, root damage, fresh wounds or a recent transplant.

The more important question is what stressed the host in the first place.

Why it matters

The beetles do not eat the wood. They farm a fungus inside their tunnels, and the fungus spreads into the surrounding tissue. In a palm, the tunnels cut water-conducting bundles that cannot be rerouted, and a palm does not wall off the damage the way a tree does.

Light activity in a recovering host may not be fatal. Heavy tunneling in a palm trunk usually is. Beetle wounds can also let in Thielaviopsis trunk rot.

When we see it

Spring flight peaks from about February through May in Southwest Florida, and activity continues year-round in warm years. Pressure is highest after hurricanes, drought, cold events and transplant cycles, and in newer communities with many recent plantings.

What we do

How Ptolemy handles it

Field condition first, then the recommendation. Treatment, removal and diagnosis calls are made by an ISA Certified Arborist, and the serious ones are confirmed in a lab.

Treat a beetle find as a stress workup first: roots, irrigation, nutrition and physical damage.
Our certified arborist judges how far the tunneling has gone. Most heavily infested hosts end in a removal recommendation.
On a high-value palm or tree the client wants to keep, or one caught early, a preventive bark spray is an arborist call, not a default.
Removed wood is destroyed, not chipped and spread on site, and the stump is ground. Removal is timed before the next brood flies.
No injection as a default route on palms. A palm cannot wall off an injection wound.

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