WDO CERTIFICATION EXAM 150 CORE
STRUCTURAL SCENARIOS WITH
CORRECT VERIFIED ANSWERS and
RATIONALES (GRADE A+, INSTANT
DOWNLOAD)
Georgia CO Exam – WDO Category
1. Under the rules of the Georgia Structural Pest Control Act, what is
the mandatory application rate of a liquid termiticide required to
treat the soil on either side of a foundation wall for a
comprehensive pre-construction or post-construction
subterranean termite soil treatment?
A. 2 gallons per 10 linear feet of foundation wall.
B. 4 gallons per 10 linear feet of foundation wall per foot of depth
from the grade to the footer.
C. 10 gallons per 10 linear feet regardless of depth or construction
type.
D. 1 gallon per 5 linear feet applied exclusively using high-pressure
injection nozzles.
Correct Answer: B
Rationale: Georgia Structural Pest Control Commission rules
mandate that liquid soil termiticides must be applied at a
minimum rate of 4 gallons per 10 linear feet per foot of depth to
create an effective continuous vertical chemical barrier against
subterranean termites.
2. A certified operator is calculating the required structural
ventilation for a residential crawl space measuring 60 feet long by
40 feet wide that does not have an installed soil vapor barrier.
According to International Residential Code standards enforced in
, structural pest control, how many standard 8" x 16" foundation
vents are required?
A. 4 vents
B. 10 vents
C. 18 vents
D. 24 vents
Correct Answer: C
Rationale: Without a vapor barrier, the minimum required net
free ventilation area is 1 square foot per 150 square feet of crawl
space floor area (60 × 40 = 2400 sq. ft. = 16 sq. ft. of
total required vent space). A standard 8" x 16" vent provides
roughly 128 square inches of net free area ( = 0.888 sq.
ft.). Therefore, .888 = 18 vents are needed.
3. On the Official Georgia Wood Infestation Inspection Report
(WIIR), which of the following is considered a reportable
"conducive condition" that must be marked and detailed by the
inspector?
A. Untreated decorative mulch situated 12 inches away from the
perimeter foundation wall.
B. Untreated structural wood components or framing in direct,
physical contact with the soil.
C. Any internal structural lumber located within 6 inches of the
crawl space ground that is certified for ground contact.
D. A residential lawn sprinkler system facing away from the crawl
space access door.
Correct Answer: B
Rationale: To be flagged as an environmental conducive
condition on the official Georgia WIIR form, untreated structural
timber must be in actual physical contact with the earth. Wood
within 6 inches of the soil that is untreated must be handled via a
waiver but is structurally distinct from absolute earth contact on
the report.
4. An operator discovers active wood-boring beetle infestations
within an old historical residence. The exit holes are determined to
be distinct, flat-oval shaped, measuring roughly 1/4 inch in
diameter. Which family or species of beetle is responsible for this
structural damage?
A. Lyctidae (True Powderpost Beetles)
, B. Anobiidae (Furniture Beetles)
C. Hylotrupes bajulus (Old House Borer)
D. Bostrichidae (False Powderpost Beetles)
Correct Answer: C
Rationale: The Old House Borer (Cerambycidae family) leaves
a characteristic flat-oval exit hole measuring roughly 1/4 inch
across, whereas powderpost families like Lyctids or Anobiids
leave much smaller, perfectly round "shot holes" packed with fine
frass.
5. According to the Georgia Department of Agriculture, how long is
an issued Official Georgia Wood Infestation Inspection Report
(WIIR) valid for most real estate transaction closings and lending
purposes?
A. 30 days from the date of the inspection.
B. 90 days from the date of the inspection.
C. 180 days, provided no rainfall has occurred in the county.
D. One full calendar year from the date the certificate is stamped.
Correct Answer: A
Rationale: Under standard lending regulations and Georgia
structural protocols, a completed WIIR is universally accepted by
lenders and buyers for a standard window of 30 days from the
execution date of the actual crawl space and perimeter inspection.
6. Which of the following wood-destroying organisms or insects is
explicitly excluded from coverage and reporting requirements on
the standard Official Georgia Wood Infestation Inspection Report?
A. Subterranean Termites (Reticulitermes spp.)
B. Carpenter Ants (Camponotus spp.) and Carpenter Bees
(Xylocopa virginica)
C. Wood-Decaying Fungi (White rot or Brown cubical rot)
D. Powderpost Beetles (Lyctinae)
Correct Answer: B
Rationale: The Georgia WIIR strictly tracks damage from true
wood-destroying organisms (termites, powderpost beetles, wood-
boring beetles, and wood-decaying fungi). It does not include
wood-destroying insects like carpenter ants or carpenter bees,
which nest in wood but do not consume it as food.
, 7. Under the Georgia Structural Pest Control Commission rules, what
is the mandatory minimum wood-to-soil clearance that must be
achieved and maintained within a residential crawl space during a
post-construction termite corrective treatment?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Correct Answer: C
Rationale: Georgia rules mandate a minimum clearance of 18
inches between the ground soil and all untreated structural floor
joists or subflooring inside a crawl space to minimize moisture
transfer and discourage subterranean termite tunneling.
8. When treating an interior concrete slab floor for a subterranean
termite infestation via drilling and sub-slab liquid injection, what
is the maximum allowable spacing between the drilled holes along
the internal foundation wall or fracture line?
A. 12 inches
B. 18 inches
C. 24 inches
D. 36 inches
Correct Answer: B
Rationale: State guidelines require that drill holes through
concrete slabs for liquid chemical barriers be spaced no further
than 18 inches apart to ensure continuous chemical lateral spread
beneath the concrete.
9. A Georgia WDO technician inspects a structure and identifies
powdery, talc-like frass loosely filling tiny, round 1/32-inch exit
holes in oak hardwood flooring. What specific wood-destroying
pest caused this issue?
A. Anobiid Beetle
B. Lyctid Beetle (True Powderpost Beetle)
C. Formosan Termite
D. Carpenter Bee
Correct Answer: B
Rationale: Lyctid beetles attack exclusively seasoned
hardwoods and leave very fine, powder-like frass resembling