7B Ch6 Cheat Sheet: Other Wood-Destroying Insects

🎯 Top 5 Traps

1

Carpenter ants do NOT eat wood — they EXCAVATE it. Galleries are very smooth-sided, brown-stained, with NO mud (vs termites) and NO internal frass or pellets (vs powderpost beetles). The sawdust pile is outside the gallery. Workers forage for honeydew, sugars, and insects — wood has no nutritional value to them.

2

Old house borer = Cerambycidae (longhorned), NOT a powderpost beetle. Only longhorned beetle that reinfests structural timbers. Long life cycle — 3 to 12 years — means structural damage may not be noticed for many years. Frequently a pest of NEW structures, not just old. Exit holes broadly oval, 1/4 to 3/8 inch.

3

Lyctidae (true) = HARDWOOD only. Bostrichidae and Anobiidae = both. Only Anobiidae can DIGEST cellulose; the other two pass it as powder. Anobiid frass contains bun-shaped fecal pellets — diagnostic.

4

Carpenter ants are MORE ACTIVE AT NIGHT — inspect after dark. Daytime inspection often misses the activity. Their nests are nearly always linked to a moisture problem, frequently in wood already infested by brown-rot fungus (look for dark fungus stains). Eliminate the moisture source FIRST.

5

Carpenter bee tunnels have NO frass. Tunnels are provisioned with POLLEN for eggs, not fecal material. Males have no stingers despite belligerent darting; females rarely sting. Females reuse tunnels year after year — failing to plug a tunnel invites next year's colony.

🔢 Numbers You Must Know

Number

What It Represents

1/8 to 1/4 inch

Lyctidae (true powderpost) adult length — slim, flat, reddish-brown to black

1/8 to 3/8 inch

Bostrichidae (false powderpost) adult length — robust, cylindrical, roughened pronotum

less than 1/3 inch

Anobiidae (furniture / deathwatch) adult length — red to brown to black, oval, compact

20 percent

Wood moisture content target — keep below this to discourage wood-boring beetle development

24 hours

Keep objects off treated wood until stickiness has disappeared (oil-based finished-wood treatment)

3/4 inch

Old house borer adult length; also black carpenter ant queen length

3 to 12 years

Old house borer life cycle — damage may not be noticed for years

1/4 to 3/8 inch

Old house borer exit hole diameter — broadly oval

1/2 inch to 3 or 4 inches

Old house borer mature larva length — round-headed borer, light cream color

1/4 to almost 1/2 inch

Black carpenter ant worker size range

1/8 inch

Wood-boring weevil adult length (Curculionidae)

1/16 inch

Wood-boring weevil tunnel diameter — heartwood or sapwood of softwoods, hardwoods, even plywood

🔀 Easily Confused

Pair / Group

Distinguishing Feature

Lyctidae vs Bostrichidae vs Anobiidae

Lyctid: hardwood ONLY, eggs in pores. Bostrichid: both hardwood and softwood, female bores INTO wood to lay eggs. Anobiid: both, mostly softwood sapwood, can DIGEST cellulose, bun-shaped pellets in coarse frass.

Old house borer vs other longhorned beetles

Old house borer: ONLY longhorned that reinfests structural timbers. Softwood (pine). Adult 3/4 in. with 2 white elytra patches and 2 black bumps with light hairs (owl-like). Other longhorned: require no control.

Carpenter ants vs Termites (damage)

Carpenter ants: SMOOTH brown-stained galleries, NO mud, NO internal frass; sawdust piled outside. Termites: galleries packed with mastic-like frass; mud tubes nearby.

Carpenter ant sawdust vs Construction sawdust

Carpenter ant: very SOFT, like fine chisel shavings. Construction: GRITTY. The distinction matters — gritty sawdust on attics or sills may simply be construction debris.

Carpenter bees vs Bumblebees

Carpenter bee: hairy yellow thorax, SHINY BLACK abdomen, solitary (no worker caste), bores in wood. Bumblebee: yellow-and-black hairy ALL OVER, social, ground or cavity nests — closely related to honeybees.

Oil-based vs Water-based wood treatment

Water-based: usually safer and more effective. Oil-based: fire hazard, more expensive, more dangerous to applicator, can damage plants — but BEST for finished wood (furniture, flooring) to avoid spotting/changing the finish.

Fumigation vs Residual sprays (borers)

Residual sprays: effective in MOST cases; flat-fan nozzle, low pressure. Fumigation: best penetration into tunnels but most hazardous, no residual life — used when sprays cannot reach (e.g., beetles in walls, widespread infestation).

🪲 Powderpost Beetle Family Reference

Family

Hosts & Body

Distinctive Feature

Lyctidae (true powderpost)

Hardwoods ONLY (sapwood for starch). 1/8 to 1/4 in. Slim, flat, reddish-brown to black.

Cannot digest cellulose. Eggs laid in wood pores. Fine powdery frass falling from surface holes — diagnostic.

Bostrichidae (false powderpost)

Hardwoods AND softwoods. 1/8 to 3/8 in. Robust, cylindrical, roughened pronotum, head not visible from above.

Cannot digest cellulose. Female bores DIRECTLY into wood to lay eggs. Rarely reinfests structural timbers.

Anobiidae (furniture / deathwatch)

Mostly softwood sapwood (all seasoned wood possible). Less than 1/3 in. Red to brown to black, oval, compact.

CAN digest cellulose. Coarse frass with bun-shaped fecal pellets. Eggs in cracks, crevices, or old exit holes. Deathwatch makes ticking sound at night.

🐛 Pest ID & Treatment Quick Reference

Pest

Key Damage Signs

Treatment Approach

Powderpost beetles (all 3 families)

Pencil-lead-size shot-holes; powder/frass sifting from holes when wood is jarred; possible packed-powder masses inside cut wood

Residual sprays at low pressure with flat-fan nozzle. Lyctids: hardwood surfaces only. Bostrichids/Anobiids: assume both. Fumigation if widespread or in inaccessible walls. Oil for finished wood.

Wood-boring weevils (Curculionidae)

Elongated snout. Found in wet/rotting wood — secondary to wood rot. 1/8 in. body, 1/16 in. tunnels in heartwood/sapwood/plywood.

Remove and replace damaged wood. Lower wood moisture. Borate insecticides may be appropriate case by case.

Old house borer (Cerambycidae)

Softwood only (e.g., pine). Adults 3/4 in. with 2 white elytra patches and owl-like pronotum hairs. Larvae 1/2 to 3-4 in. Exit holes 1/4 to 3/8 in. broadly oval. Damage delayed 3 to 12 years.

Treat softwoods only. Spot residual treatment for limited damage. Fumigation if widespread or in walls. Bring firewood indoors only when it will be used soon.

Carpenter ants (Camponotus)

SMOOTH brown-stained galleries — no mud, no internal frass. Soft chisel-shaving sawdust piled outside. Workers 1/4 to 1/2 in.; queen 3/4 in. Active at night. Petiole has 1 node; smooth thoracic profile (vs field ants' bumps).

Eliminate moisture source FIRST. Pesticidal dust or pressurized aerosols in wall voids — sprays less effective. Liberal bait stations for indirect treatment. Outside colonies (tree rot): dust, spray, or bait. Trim trees touching the structure; caulk and screen entryways.

Carpenter bees (Xylocopa)

Large bee with hairy yellow thorax and SHINY BLACK abdomen. Bumblebee look-alike. Solitary, 1-yr life. Drill end grain or face, then turn and tunnel WITH grain. NO frass — tunnels provisioned with POLLEN.

Dust tunnels or inject pressurized liquid insecticide. Insert dusted plug of steel wool or copper gauze. Fill opening with caulk, wood filler, or wooden dowel. Plug stops next year's emerging adults.

💡 Memory Hooks

Powderpost families — "L-B-A": L yctid L imited to hardwood. B ostrichid B oth woods, B ores in to lay eggs. A nobiid A te cellulose (digests it) — bun-shaped pellets.

Old house borer: "3/4 inch beetle, 3 to 12 year life — damage delayed for YEARS." Long life means structural damage often shows up well after the infestation took hold.

Carpenter ants: "Shave, don't swallow." Wood has no nutritional value to them. Smooth galleries, no internal frass, soft sawdust outside.

Inspection timing: "Ants by night, ducts by day." Carpenter ants are most active after dark — bring a flashlight.

Carpenter bees: "Pollen in, frass out." Tunnels are provisioned with pollen — no frass should be inside. Always plug with a dusted steel-wool or copper-gauze plug, then caulk.