Tiny Rows of Holes in a Florida Tree Trunk: Borers, Beetles, or Something Else?

The pattern is often more informative than the fact that holes exist.

Neat horizontal rows can point toward sapsucker feeding. Fresh round holes with powder, frass tubes, resin, or rapid canopy change may point toward bark or ambrosia beetles. Irregular marks can come from old hardware, straps, tools, pruning, or mechanical injury.

Do not spray the trunk or inject the holes before the tree, pattern, and likely cause are identified.

Start with a pattern matrix

Pattern or evidence	Possible cause	What to document
Neat horizontal rows of shallow holes	Sapsucker feeding	Row spacing, fresh sap, bird activity
Repeated rectangular or banded pattern	Sapsucker or old mechanical pattern	Whether holes are fresh or callused
Tiny round holes with powder	Bark or wood-boring insect	Fresh dust, host, crown change
Toothpick-like frass tubes	Ambrosia beetle activity	Number, freshness, wilt, branch dieback
Resin or pitch tubes on pine	Bark-beetle defense response	Pitch color, boring dust, crown color
D-shaped, oval, or species-specific exit holes	Certain borers	Host species and exact hole shape
Uniform holes near old straps or signs	Hardware or mechanical injury	Metal, wire, spacing, history
Holes around dead branch stub	Decay, insects, old wound	Branch condition and surrounding bark
One cavity or large opening	Wildlife, decay, wound	Location, edges, internal material

The same hole shape can have different causes on different host trees.

Sapsucker rows

Yellow-bellied sapsuckers and related birds can drill orderly rows to obtain sap and insects.

Clues include:

• repeated horizontal lines,
• multiple bands from different seasons,
• shallow holes,
• fresh sap,
• bird activity,
• an otherwise stable crown.

Sapsucker activity can injure a tree when repeated heavily, but many trees tolerate limited feeding.

Most native migratory birds are federally protected. Do not trap, harm, or destroy active nests without authorization.

Ambrosia-beetle clues

Ambrosia beetles can produce:

• very small entry holes,
• fine boring dust,
• compacted frass,
• toothpick-like tubes,
• wilt,
• branch dieback,
• attack on stressed, cut, dying, or recently killed wood.

Different species have different hosts and behavior. Some carry fungi; others are primarily associated with stressed or dead material.

A “toothpick” clue should prompt identification, not an immediate generic spray.

Bark beetles and pines

On pines, look for:

• pitch tubes,
• boring dust,
• crown fading from green to yellow or red-brown,
• bark loosening,
• multiple attacks,
• nearby stressed pines.

UF/IFAS notes that Ips engraver beetles can colonize stressed pines and may be associated with rapid crown change.

The host species and timing are essential.

Holes can be old

Old holes may be:

• dry,
• dark,
• callused,
• covered by new bark,
• inactive,
• associated with a past wound.

Fresh activity is more likely when there is:

• new dust,
• new frass,
• wet resin,
• active insects,
• expanding bark damage,
• new wilt or dieback.

Do not peel bark to “check the gallery.” That can enlarge the wound and destroy evidence.

Mechanical marks

Ask whether the trunk previously held:

• a sign,
• wire,
• holiday lights,
• a chain,
• hammock hardware,
• fence attachment,
• support system,
• climbing spikes,
• equipment contact.

Embedded metal must be disclosed before pruning or removal.

Holes do not measure structural strength

Small holes do not show:

• extent of internal decay,
• remaining shell,
• root anchorage,
• crack movement,
• load path.

A tree with many insect holes may still require a separate structural assessment. A structurally defective tree may have no visible insect holes.

Do not tap the trunk as a homeowner “hollow test.”

Photograph before collecting or treating

Photograph:

• whole tree,
• leaves or needles,
• bark,
• hole rows,
• close view with a scale,
• frass or dust,
• resin or fluid,
• branch dieback,
• trunk base,
• nearby targets.

Record:

• tree species,
• date first observed,
• recent pruning,
• storm or construction history,
• pesticide use,
• nearby affected trees.

Identification and reporting

When the pest is uncertain:

• contact UF/IFAS Extension,
• use a plant diagnostic clinic,
• consult the Florida Forest Service,
• submit an appropriate specimen when advised.

Florida agriculture and forest-health agencies may request reporting for regulated or emerging pests.

Do not move infested firewood or cut material until disposal guidance is understood.

Pesticide decisions are pest-specific

A valid treatment decision requires:

• confirmed or likely pest,
• host species,
• life stage,
• timing,
• tree condition,
• product registration,
• current label,
• application site,
• applicator role,
• environmental restrictions.

Spraying into visible holes is not a universal treatment and may be too late for an insect already protected inside wood.

When pruning may help

Pruning may be appropriate when:

• infestation is limited to a removable branch,
• the branch can be removed without excessive crown loss,
• disposal is managed,
• the tree remains sustainable,
• wildlife and utilities are clear.

When removal becomes more likely

Removal discussion is more appropriate when:

• the tree is dead,
• decline is irreversible,
• infestation is widespread,
• major structural defects coexist,
• roots or trunk are unstable,
• targets are high consequence,
• treatment is unlikely to preserve a sustainable tree.

Use the removal-decision hub rather than deciding from hole count alone.

Route the work

ProTreeTrim can help connect Florida property owners with local providers for defined tree trimming, authorized tree removal, or emergency response after pest identification, utility, wildlife, and structural questions are clear. Call (855) 498-2578.

ProTreeTrim is a referral and dispatch network, not an entomology laboratory, pesticide regulator, wildlife agency, utility, tree-risk assessor, or licensed contractor. Verify identification, labels, reporting, credentials, insurance, permits, and scope with the responsible professionals.

Sources and further reading

• UF/IFAS: A Guide to Florida’s Common Bark and Ambrosia Beetles
• UF/IFAS: Ambrosia Beetles, Platypus Species
• UF/IFAS: Ips Engraver Beetles
• Penn State Extension: Mysterious Holes in Trees and Sapsuckers
• Florida Forest Service: Forest Insects
• Florida Department of Agriculture: Submit Forest Pest Specimens