Skip to content
LTK
ACE
Menu
ACE Prep FreeStudy guide, 277 practice questions, flashcards and a speed round.Recruit0 XP · Agent file
Join the Discord(opens Discord in a new tab)How to join

ACE Prep · Module 11 of 11

Wood Destroying Insects

Quick answerUpdated September 24, 2026

What does ACE module 11 cover?

WDI includes termites (subterranean, drywood, and dampwood), wood-boring beetles (powderpost, false powderpost, anobiid, and old house borer), and carpenter ants. Correct species identification is critical because treatment methods, access, and expectations differ dramatically.

Key factApproximate exam weight: ~8%.

Reviewed by LTK editorial team

Must-know facts

  • Termite castes: workers, soldiers, reproductives (primary = alates/swarmers; secondary = neotenic). Soldiers or swarmers needed for ID.
  • Termites digest wood with protozoa, bacteria, and enzymes. Nymphs obtain protozoa through trophallaxis (food sharing with workers).
  • Ant vs. termite ID: termites have no waist constriction, straight antennae, equal-length wing pairs. Ants have a waist, elbowed antennae, unequal wing pairs.
  • Eastern subterranean termite (Reticulitermes flavipes): most common US species, 50,000–350,000+ colony, spring swarms, 2 veins on swarmer wing, smooth soldier mandibles.
  • Formosan subterranean termite (Coptotermes formosanus): 1,000,000+ colony, 10% soldiers, teardrop-shaped soldier head, yellowish-orange hairy swarmers that swarm at night.
  • Drywood termites (Kalotermitidae): no ground contact, wood moisture <15%, serrated mandibles, 4 anterior veins on swarmer wing. Produce hard dry hexagonal fecal pellets.
  • Dampwood termites: require moisture in wood, not subterranean. Larger than subterranean. Serrated mandibles.
  • True powderpost beetles (Lyctidae/Bostrichidae subfamily Lyctinae): 1/32–1/8 inch exit holes, fine silky frass, hardwoods ONLY.
  • False powderpost beetles (Bostrichidae): 1/16–5/16 inch exit holes, coarse tightly-packed frass, soft and hardwoods. Tend NOT to reinfest.
  • Anobiid beetles: 1/16–1/8 inch exit holes, elongated loosely-packed frass, prefer >15% wood moisture, hard and softwoods.
  • Old house borer (Cerambycidae): oval 3/8-inch exit holes, coarse frass with fine striations in damaged wood, attacks softwoods <10 years old.
  • Carpenter ants: polymorphic, single node, rounded thorax profile, frass contains sawdust + insect parts + pupal cases. Excavate wood for nesting, do NOT eat it. Primary and satellite colonies.

What the exam likes to ask

  • Drywood termite = dry fecal pellets, no soil contact, serrated mandibles, hardwood in <15% moisture.
  • True powderpost beetles = hardwood ONLY, fine silky frass, small round holes.
  • Carpenter ant frass has insect fragments and pupal cases — this is not present in termite frass.
  • Formosan termites have the largest colonies (1M+) and 10% soldiers — swarm at night.

Field takeaways

  • Know the frass and hole characteristics for each WDI species — this is a core part of field WDO inspections.
  • Carpenter ants in a structure almost always mean moisture — find and fix the moisture issue or the colony will persist.
  • Drywood termite control often requires tent fumigation for whole-structure elimination — localized treatments have limitations.

Listen, watch, read

Podcast

Identifying Termites, Beetles, and Carpenter Ants

WDI differentiation — how to tell subterranean vs. drywood termites, powderpost beetles, and carpenter ants apart in the field.

Slide deck · 13 slides

WDI Inspector Blueprint

View the slides

Hidden Housewreckers

9:07

Wood Destroying Insects 1

9:10

Wood Destroying Insects 2

9:25

ACE Prep: Wood Insects

9:00

Module 11 quiz

26 questions. Answer them all, then grade to see the reasoning.

  1. Q1Why can a termite worker not digest wood for a while right after it molts?
  2. Q2Termites are found in attic framing of a coastal Southern California home. There is no soil contact and no mud tubes. Which group is most likely?
  3. Q3True powderpost beetles (subfamily Lyctinae, family Bostrichidae) attack
  4. Q4Which Formosan subterranean termite character most helps distinguish it from eastern subterranean termites?
  5. Q5Carpenter ants differ from termites in that carpenter ants
  6. Q6Drywood termite fecal pellets are best described as
  7. Q7Which termite caste does most of the feeding and causes the damage to wood?
  8. Q8On a warm spring morning after rain, dark-bodied termite swarmers emerge inside a Midwest home. The most likely genus is
  9. Q9On a humid May evening in New Orleans, clouds of yellowish-brown termite swarmers gather around porch lights. They are most likely
  10. Q10Subterranean termites build mud shelter tubes mainly to
  11. Q11Drywood termites are active throughout attic framing and in several areas that cannot be reached. Which treatment is most likely to eliminate every colony?
  12. Q12Large termites are found only in a section of rotting, water-soaked wood under a leaking window. They have no soil contact or mud tubes. Which step matters most?
  13. Q13In Arizona, a technician finds mud tubes hanging down from a ceiling, not attached to any wall. These drop tubes are typical of
  14. Q14A termite soldier has mandibles with prominent teeth along the inner edge. It most likely belongs to
  15. Q15A termite swarmer's front wing has three or more heavy, dark veins along the leading edge. This points to
  16. Q16Which of these soil termiticides is non-repellent?
  17. Q17Why do termite bait systems usually take weeks to months to eliminate a colony?
  18. Q18Which condition most increases the risk of subterranean termites?
  19. Q19Fine, talc-like powder is sifting out of tiny round holes in new oak flooring. The most likely cause is
  20. Q20Pine joists in a humid crawlspace in the Southeast have many round holes about 1/16 to 1/8 inch across and gritty frass with small pellets. The most likely pest is
  21. Q21For an anobiid infestation in crawlspace framing, the most important long-term step is to
  22. Q22Pine framing has oval exit holes about 1/4 to 3/8 inch across, galleries with ripple-like marks on the walls, and tightly packed powdery frass. The most likely pest is the
  23. Q23Borate wood treatments, such as disodium octaborate tetrahydrate, must be applied to
  24. Q24A cylindrical beetle whose head is hidden from above under a hood-like pronotum emerges from imported hardwood, leaving round holes and coarse, tightly packed frass. It is most likely a
  25. Q25Perfectly round holes about 1/2 inch across appear on the underside of bare softwood fascia boards, with coarse sawdust below and large, shiny bees hovering nearby in spring. The most likely pest is
  26. Q26Piles of shed wings, all the same size and shape, are found on an indoor windowsill. This most likely means

0 of 26 answered

LTK Discord

The conversation is already happening.

Techs, owners and rookies trading notes every day — pest ID help, podcast drops, group training nights and plenty of shop talk. Free to join, no licence check required to say hello.

Join the Discord(opens Discord in a new tab)