Ohio Pesticide Applicator Certification:
Category 6a – Ornamental Weed
Control
100 Question & Answer Review for 2025
Examination
Section 1: Weed Identification & Biology (Questions 1-15)
1. Which characteristic is typical of a perennial weed?
A) Completes its life cycle in one growing season
B) Dies back to the ground each winter but regrows from roots or rhizomes
C) Has a shallow, fibrous root system
D) Primarily spreads by seed only
Answer: B) Dies back to the ground each winter but regrows from roots or rhizomes
Rationale: Perennial weeds survive for multiple years, typically regrowing from underground
vegetative structures like rhizomes, tubers, or crowns.
2. A weed with a parallel-veined leaf and a single seed leaf (cotyledon) upon emergence is
classified as a:
A) Broadleaf weed
B) Dicot
C) Woody plant
D) Grassy or grass-like weed
Answer: D) Grassy or grass-like weed
Rationale: Monocots (grasses, sedges, rushes) have one seed leaf, parallel leaf veins, and
typically fibrous root systems.
3. Yellow nutsedge (Cyperus esculentus) can be identified by:
A) A triangular stem in cross-section
B) A square stem
C) Opposite leaf arrangement
D) A taproot
,Answer: A) A triangular stem in cross-section
Rationale: Sedges have edges; the stem is solid and triangular. "Sedges have edges, rushes are
round, grasses have nodes all the way to the ground."
4. Which weed is often a indicator of poorly drained, compacted soils in ornamental
landscapes?
A) Dandelion
B) Crabgrass
C) Annual bluegrass (Poa annua)
D) Moss
Answer: D) Moss
Rationale: Moss is not a true weed but a symptom of conditions unfavorable for turfgrass:
shade, low soil fertility, poor drainage, acid pH, or compaction.
5. A weed that germinates and flowers in the same year, then dies, is a(n):
A) Winter annual
B) Biennial
C) Simple perennial
D) Summer annual
Answer: D) Summer annual
Rationale: Summer annuals germinate in spring, grow, set seed, and die in one season. (Winter
annuals germinate in fall, overwinter, and seed in spring).
6. The primary purpose of identifying a weed before selecting a control method is to:
A) Determine its ornamental value
B) Assess its life cycle and vulnerable growth stages
C) Estimate its market value
D) Decide if it is native or not
Answer: B) Assess its life cycle and vulnerable growth stages
Rationale: Effective control depends on knowing if it's annual/perennial, grass/broadleaf, and its
reproductive strategy (seeds vs. vegetative structures).
Section 2: Herbicide Chemistry & Formulations (Questions 7-25)
7. An herbicide that moves within the plant, typically from leaves to roots, is called:
A) Contact
B) Systemic
C) Pre-emergent
D) Nonselective
, Answer: B) Systemic
Rationale: Systemic (translocated) herbicides are absorbed and move throughout the plant's
vascular system to kill roots, rhizomes, and other tissues.
8. Which formulation is most likely to cause vapor drift?
A) Wettable powder (WP)
B) Soluble concentrate (SC)
C) Granular (G)
D) Ester formulation of a herbicide
Answer: D) Ester formulation of a herbicide
Rationale: Ester formulations have higher volatility (can vaporize) compared to amine salts,
especially under warm conditions, posing a significant off-target drift risk.
9. A common adjuvant added to the spray tank to improve herbicide coverage and
penetration is a:
A) Drift control agent
B) Safener
C) Surfactant
D) Buffer
Answer: C) Surfactant
Rationale: Surfactants reduce surface tension, allowing spray droplets to spread and stick to
waxy leaf surfaces for better absorption.
10. Which statement about granular herbicides is TRUE?
A) They are ideal for foliar application to existing weeds.
B) They require complete leaf coverage for effectiveness.
C) They are often used as pre-emergents and require irrigation or rainfall for activation.
D) They pose the highest risk of spray drift.
Answer: C) They are often used as pre-emergents and require irrigation or rainfall for
activation.
Rationale: Granular herbicides are applied to soil and must be watered in to release the active
ingredient into the weed germination zone.
11. The signal word "Danger-Poison" with a skull and crossbones on a label indicates:
A) Moderate skin irritation potential
B) High risk of plant phytotoxicity
C) High acute toxicity if ingested, inhaled, or absorbed
D) The product is a restricted use pesticide (RUP)
Answer: C) High acute toxicity if ingested, inhaled, or absorbed
Category 6a – Ornamental Weed
Control
100 Question & Answer Review for 2025
Examination
Section 1: Weed Identification & Biology (Questions 1-15)
1. Which characteristic is typical of a perennial weed?
A) Completes its life cycle in one growing season
B) Dies back to the ground each winter but regrows from roots or rhizomes
C) Has a shallow, fibrous root system
D) Primarily spreads by seed only
Answer: B) Dies back to the ground each winter but regrows from roots or rhizomes
Rationale: Perennial weeds survive for multiple years, typically regrowing from underground
vegetative structures like rhizomes, tubers, or crowns.
2. A weed with a parallel-veined leaf and a single seed leaf (cotyledon) upon emergence is
classified as a:
A) Broadleaf weed
B) Dicot
C) Woody plant
D) Grassy or grass-like weed
Answer: D) Grassy or grass-like weed
Rationale: Monocots (grasses, sedges, rushes) have one seed leaf, parallel leaf veins, and
typically fibrous root systems.
3. Yellow nutsedge (Cyperus esculentus) can be identified by:
A) A triangular stem in cross-section
B) A square stem
C) Opposite leaf arrangement
D) A taproot
,Answer: A) A triangular stem in cross-section
Rationale: Sedges have edges; the stem is solid and triangular. "Sedges have edges, rushes are
round, grasses have nodes all the way to the ground."
4. Which weed is often a indicator of poorly drained, compacted soils in ornamental
landscapes?
A) Dandelion
B) Crabgrass
C) Annual bluegrass (Poa annua)
D) Moss
Answer: D) Moss
Rationale: Moss is not a true weed but a symptom of conditions unfavorable for turfgrass:
shade, low soil fertility, poor drainage, acid pH, or compaction.
5. A weed that germinates and flowers in the same year, then dies, is a(n):
A) Winter annual
B) Biennial
C) Simple perennial
D) Summer annual
Answer: D) Summer annual
Rationale: Summer annuals germinate in spring, grow, set seed, and die in one season. (Winter
annuals germinate in fall, overwinter, and seed in spring).
6. The primary purpose of identifying a weed before selecting a control method is to:
A) Determine its ornamental value
B) Assess its life cycle and vulnerable growth stages
C) Estimate its market value
D) Decide if it is native or not
Answer: B) Assess its life cycle and vulnerable growth stages
Rationale: Effective control depends on knowing if it's annual/perennial, grass/broadleaf, and its
reproductive strategy (seeds vs. vegetative structures).
Section 2: Herbicide Chemistry & Formulations (Questions 7-25)
7. An herbicide that moves within the plant, typically from leaves to roots, is called:
A) Contact
B) Systemic
C) Pre-emergent
D) Nonselective
, Answer: B) Systemic
Rationale: Systemic (translocated) herbicides are absorbed and move throughout the plant's
vascular system to kill roots, rhizomes, and other tissues.
8. Which formulation is most likely to cause vapor drift?
A) Wettable powder (WP)
B) Soluble concentrate (SC)
C) Granular (G)
D) Ester formulation of a herbicide
Answer: D) Ester formulation of a herbicide
Rationale: Ester formulations have higher volatility (can vaporize) compared to amine salts,
especially under warm conditions, posing a significant off-target drift risk.
9. A common adjuvant added to the spray tank to improve herbicide coverage and
penetration is a:
A) Drift control agent
B) Safener
C) Surfactant
D) Buffer
Answer: C) Surfactant
Rationale: Surfactants reduce surface tension, allowing spray droplets to spread and stick to
waxy leaf surfaces for better absorption.
10. Which statement about granular herbicides is TRUE?
A) They are ideal for foliar application to existing weeds.
B) They require complete leaf coverage for effectiveness.
C) They are often used as pre-emergents and require irrigation or rainfall for activation.
D) They pose the highest risk of spray drift.
Answer: C) They are often used as pre-emergents and require irrigation or rainfall for
activation.
Rationale: Granular herbicides are applied to soil and must be watered in to release the active
ingredient into the weed germination zone.
11. The signal word "Danger-Poison" with a skull and crossbones on a label indicates:
A) Moderate skin irritation potential
B) High risk of plant phytotoxicity
C) High acute toxicity if ingested, inhaled, or absorbed
D) The product is a restricted use pesticide (RUP)
Answer: C) High acute toxicity if ingested, inhaled, or absorbed
