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Illinois Sub-Category D (Turf) and Sub-Category
E (Ornamental) Exam | Latest Verified Questions
and Detailed Answers
OVERVIEW DESCRIPTION:
This Comprehensive set of multiple choice questions is designed for the Illinois Pesticide
Applicator Certification exams in Sub-category D (Turf Pest Control) and Sub-category E
(Ornamental Pest Control), administered by the Illinois Department of Agriculture. The
questions assess practical knowledge across core topics including turfgrass identification
and cultural practices, weed management, insect and disease diagnosis, thatch
management, ornamental plant identification, tree and shrub insects, plant diseases, abiotic
disorders, and integrated pest management (IPM). Content also covers pesticide
formulations, application equipment calibration, and environmentally responsible control
strategies critical for safe, effective turf and landscape care.
QUESTION 1
Which of the following turfgrass species is classified as a warm-season grass that
spreads by both stolons and rhizomes and goes dormant after the first hard frost in
Illinois?
A. Kentucky bluegrass
B. Perennial ryegrass
C. Zoysiagrass
D. Fine fescue
CORRECT ANSWER: C
EXPERT RATIONALE: Zoysiagrass is a warm-season grass that turns straw-colored after
frost; it spreads by stolons and rhizomes, unlike the cool-season grasses listed.
QUESTION 2
What is the recommended mowing height range for Kentucky bluegrass lawns in Illinois
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to promote root development and weed suppression?
A. 1.0–1.5 inches
B. 2.5–3.5 inches
C. 4.0–5.0 inches
D. 0.5–1.0 inches
CORRECT ANSWER: B
EXPERT RATIONALE: Mowing Kentucky bluegrass at 2.5–3.5 inches encourages deeper
roots, shades the soil to reduce weed germination, and improves drought tolerance.
QUESTION 3
Which cool-season turfgrass is known for its boat-shaped leaf tip, folded vernation, and
aggressive rhizomatous growth habit?
A. Tall fescue
B. Perennial ryegrass
C. Kentucky bluegrass
D. Creeping bentgrass
CORRECT ANSWER: C
EXPERT RATIONALE: Kentucky bluegrass can be identified by a distinct boat-shaped leaf
tip, folded vernation in the bud, and strong rhizomes that form a dense sod.
QUESTION 4
In Illinois, cool-season turfgrasses experience their most vigorous root and shoot growth
during which period?
A. Midsummer
B. Late fall through winter
C. Spring and early fall
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D. Late winter
CORRECT ANSWER: C
EXPERT RATIONALE: Cool-season grasses grow best when soil temperatures are
between 50–65 °F, which occurs in spring and early fall; high summer heat slows growth.
QUESTION 5
Applying high rates of nitrogen fertilizer to cool-season turf in late spring and summer
increases susceptibility to which disease?
A. Necrotic ring spot
B. Brown patch
C. Dollar spot
D. Rust
CORRECT ANSWER: B
EXPERT RATIONALE: Excess nitrogen produces lush, succulent leaf tissue that is highly
vulnerable to brown patch (Rhizoctonia solani) under warm, humid conditions.
QUESTION 6
An established turf area should be irrigated in a manner that:
A. Provides light, frequent sprinklings daily
B. Wets only the top 1 inch of soil to cool the canopy
C. Applies water deeply and infrequently to encourage deep rooting
D. Keeps the thatch layer constantly moist
CORRECT ANSWER: C
EXPERT RATIONALE: Deep, infrequent irrigation promotes a deep root system that can
access subsoil moisture, making turf more resilient to drought and pest pressure.
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QUESTION 7
Which of the following is a summer annual grassy weed that germinates when soil
temperatures reach approximately 55 °F for several consecutive days?
A. White clover
B. Large crabgrass
C. Yellow nutsedge
D. Dandelion
CORRECT ANSWER: B
EXPERT RATIONALE: Crabgrass is a summer annual that begins germination when soil
temperatures at 2-inch depth reach about 55 °F, typically around the time forsythia
blooms.
QUESTION 8
A preemergence herbicide targeting crabgrass should be applied:
A. After crabgrass seedlings have emerged and are tillering
B. When daytime temperatures consistently exceed 90 °F
C. Two to three weeks before the expected germination window
D. Only as a spot treatment in late summer
CORRECT ANSWER: C
EXPERT RATIONALE: Preemergence herbicides form a chemical barrier in the soil and
must be in place before crabgrass seeds germinate; early spring application is critical.
QUESTION 9
Yellow nutsedge can be distinguished from grasses by its:
A. Round, hollow stems and extensive rhizomes
B. Triangular (three-sided) stem and glossy, light green leaves
C. Deep taproot and milky sap
Illinois Sub-Category D (Turf) and Sub-Category
E (Ornamental) Exam | Latest Verified Questions
and Detailed Answers
OVERVIEW DESCRIPTION:
This Comprehensive set of multiple choice questions is designed for the Illinois Pesticide
Applicator Certification exams in Sub-category D (Turf Pest Control) and Sub-category E
(Ornamental Pest Control), administered by the Illinois Department of Agriculture. The
questions assess practical knowledge across core topics including turfgrass identification
and cultural practices, weed management, insect and disease diagnosis, thatch
management, ornamental plant identification, tree and shrub insects, plant diseases, abiotic
disorders, and integrated pest management (IPM). Content also covers pesticide
formulations, application equipment calibration, and environmentally responsible control
strategies critical for safe, effective turf and landscape care.
QUESTION 1
Which of the following turfgrass species is classified as a warm-season grass that
spreads by both stolons and rhizomes and goes dormant after the first hard frost in
Illinois?
A. Kentucky bluegrass
B. Perennial ryegrass
C. Zoysiagrass
D. Fine fescue
CORRECT ANSWER: C
EXPERT RATIONALE: Zoysiagrass is a warm-season grass that turns straw-colored after
frost; it spreads by stolons and rhizomes, unlike the cool-season grasses listed.
QUESTION 2
What is the recommended mowing height range for Kentucky bluegrass lawns in Illinois
,2|Page
to promote root development and weed suppression?
A. 1.0–1.5 inches
B. 2.5–3.5 inches
C. 4.0–5.0 inches
D. 0.5–1.0 inches
CORRECT ANSWER: B
EXPERT RATIONALE: Mowing Kentucky bluegrass at 2.5–3.5 inches encourages deeper
roots, shades the soil to reduce weed germination, and improves drought tolerance.
QUESTION 3
Which cool-season turfgrass is known for its boat-shaped leaf tip, folded vernation, and
aggressive rhizomatous growth habit?
A. Tall fescue
B. Perennial ryegrass
C. Kentucky bluegrass
D. Creeping bentgrass
CORRECT ANSWER: C
EXPERT RATIONALE: Kentucky bluegrass can be identified by a distinct boat-shaped leaf
tip, folded vernation in the bud, and strong rhizomes that form a dense sod.
QUESTION 4
In Illinois, cool-season turfgrasses experience their most vigorous root and shoot growth
during which period?
A. Midsummer
B. Late fall through winter
C. Spring and early fall
,3|Page
D. Late winter
CORRECT ANSWER: C
EXPERT RATIONALE: Cool-season grasses grow best when soil temperatures are
between 50–65 °F, which occurs in spring and early fall; high summer heat slows growth.
QUESTION 5
Applying high rates of nitrogen fertilizer to cool-season turf in late spring and summer
increases susceptibility to which disease?
A. Necrotic ring spot
B. Brown patch
C. Dollar spot
D. Rust
CORRECT ANSWER: B
EXPERT RATIONALE: Excess nitrogen produces lush, succulent leaf tissue that is highly
vulnerable to brown patch (Rhizoctonia solani) under warm, humid conditions.
QUESTION 6
An established turf area should be irrigated in a manner that:
A. Provides light, frequent sprinklings daily
B. Wets only the top 1 inch of soil to cool the canopy
C. Applies water deeply and infrequently to encourage deep rooting
D. Keeps the thatch layer constantly moist
CORRECT ANSWER: C
EXPERT RATIONALE: Deep, infrequent irrigation promotes a deep root system that can
access subsoil moisture, making turf more resilient to drought and pest pressure.
, 4|Page
QUESTION 7
Which of the following is a summer annual grassy weed that germinates when soil
temperatures reach approximately 55 °F for several consecutive days?
A. White clover
B. Large crabgrass
C. Yellow nutsedge
D. Dandelion
CORRECT ANSWER: B
EXPERT RATIONALE: Crabgrass is a summer annual that begins germination when soil
temperatures at 2-inch depth reach about 55 °F, typically around the time forsythia
blooms.
QUESTION 8
A preemergence herbicide targeting crabgrass should be applied:
A. After crabgrass seedlings have emerged and are tillering
B. When daytime temperatures consistently exceed 90 °F
C. Two to three weeks before the expected germination window
D. Only as a spot treatment in late summer
CORRECT ANSWER: C
EXPERT RATIONALE: Preemergence herbicides form a chemical barrier in the soil and
must be in place before crabgrass seeds germinate; early spring application is critical.
QUESTION 9
Yellow nutsedge can be distinguished from grasses by its:
A. Round, hollow stems and extensive rhizomes
B. Triangular (three-sided) stem and glossy, light green leaves
C. Deep taproot and milky sap
