OHIO PESTICIDE APPLICATOR CERTIFICATION: CATEGORY 6A – ORNAMENTAL WEED CONTROL QUESTIONS
AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
Weed Identification and Biology (Annual, Biennial, Perennial Grasses/Broadleaves)
Herbicide Modes of Action and Classification
Application Equipment and Calibration
Environmental Fate and Non-Target Protection
Integrated Pest Management (IPM) in Ornamentals
*Ohio Administrative Code (OAC) Chapter 901:5-11 – Pesticide Applicator Regulations*
Label Comprehension and Restricted-Use Pesticides
Recordkeeping, Worker Protection Standard (WPS), and Decontamination
Site-Specific Weed Control in Nurseries, Landscapes, and Greenhouses
Professional Ethics and Stewardship
Introduction
*This comprehensive examination assesses candidate knowledge and decision-making skills required for Ohio
Pesticide Applicator Certification in Category 6a – Ornamental Weed Control. The test measures competency in
weed biology, herbicide selection, safe application techniques, legal compliance, and environmental protection.
Questions are structured as multiple-choice and scenario-based items that reflect real-world challenges faced
by certified applicators in nurseries, landscapes, and greenhouses. Emphasis is placed on label interpretation,
integrated pest management, and ethical stewardship. Each correct answer is followed by a rationale to
,reinforce learning. This assessment aligns with Ohio’s regulatory standards for commercial ornamental weed
control.*
SECTION ONE: QUESTIONS 1–100
Question 1
A landscape contractor applies a pre-emergence herbicide to a bed of established daylilies in early March.
Which of the following best explains the primary mode of action of most pre-emergence herbicides used for
ornamental weed control?
A. Inhibition of photosynthetic electron transport
B. Disruption of cell membrane integrity via lipid peroxidation
C. Inhibition of root and shoot growth by disrupting cell division
D. Uncoupling of oxidative phosphorylation
🟢C
🔴 RATIONALE: Most pre-emergence herbicides (e.g., dithiopyr, pendimethalin, prodiamine) inhibit cell division
by disrupting microtubule assembly or inhibiting very-long-chain fatty acids, preventing seedling root and
shoot development.
Question 2
An applicator notices a dense patch of yellow nutsedge (Cyperus esculentus) in a container nursery. Which
herbicide mode of action is specifically effective against sedges while being safe around most established
woody ornamentals?
,A. EPSP synthase inhibitor (glyphosate)
B. Acetolactate synthase (ALS) inhibitor (halosulfuron)
C. Photosystem II inhibitor (atrazine)
D. Synthetic auxin (2,4-D)
🟢B
🔴 RATIONALE: Halosulfuron is an ALS inhibitor labeled for nutsedge control in ornamental nurseries; it is
absorbed through foliage and roots and selectively controls sedges without injuring many broadleaf
ornamentals.
Question 3
According to Ohio Administrative Code (OAC) 901:5-11, a commercial applicator applying a Restricted-Use
Pesticide (RUP) for ornamental weed control must:
A. Complete a WPS handler training every two years
B. Obtain a written prescription from a licensed veterinarian
C. Possess a valid Ohio Commercial Pesticide Applicator license with Category 6a
D. Notify all adjacent property owners 72 hours before application
🟢C
🔴 RATIONALE: OAC 901:5-11-03 requires that any person applying a restricted-use pesticide for hire must
hold the appropriate commercial applicator license category (here, 6a).
Question 4
Which of the following weed life cycles is most effectively managed by a fall-applied pre-emergence herbicide
in an ornamental planting bed?
, A. Summer annual broadleaf
B. Winter annual broadleaf
C. Perennial grass with rhizomes
D. Biennial thistle
🟢B
🔴 RATIONALE: Winter annuals (e.g., henbit, common chickweed, annual bluegrass) germinate in late summer
or fall. Fall pre-emergence application targets their emergence before winter dormancy.
Question 5
A certified applicator is calibrating a boomless sprayer for a landscape bed containing newly planted crabapple
trees. The label rate is 2 quarts per acre. The applicator covers a 1000 sq ft test area and catches 650 mL of
spray. The sprayer output is 20 gallons per minute, and ground speed is 3 mph. What is the first recommended
action?
A. Increase ground speed to 4 mph
B. Reduce nozzle orifice size
C. Recalculate based on actual measured output per 1000 sq ft
D. Add a drift reduction adjuvant
🟢C
🔴 RATIONALE: Calibration requires matching actual applied volume to target rate. The test catch shows
output; the applicator must compute gallons per 1000 sq ft and compare to label’s per-acre equivalent before
adjusting speed or nozzles.
Question 6
Which of the following best describes the Ohio Revised Code’s requirement for posting treated ornamental
AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
Weed Identification and Biology (Annual, Biennial, Perennial Grasses/Broadleaves)
Herbicide Modes of Action and Classification
Application Equipment and Calibration
Environmental Fate and Non-Target Protection
Integrated Pest Management (IPM) in Ornamentals
*Ohio Administrative Code (OAC) Chapter 901:5-11 – Pesticide Applicator Regulations*
Label Comprehension and Restricted-Use Pesticides
Recordkeeping, Worker Protection Standard (WPS), and Decontamination
Site-Specific Weed Control in Nurseries, Landscapes, and Greenhouses
Professional Ethics and Stewardship
Introduction
*This comprehensive examination assesses candidate knowledge and decision-making skills required for Ohio
Pesticide Applicator Certification in Category 6a – Ornamental Weed Control. The test measures competency in
weed biology, herbicide selection, safe application techniques, legal compliance, and environmental protection.
Questions are structured as multiple-choice and scenario-based items that reflect real-world challenges faced
by certified applicators in nurseries, landscapes, and greenhouses. Emphasis is placed on label interpretation,
integrated pest management, and ethical stewardship. Each correct answer is followed by a rationale to
,reinforce learning. This assessment aligns with Ohio’s regulatory standards for commercial ornamental weed
control.*
SECTION ONE: QUESTIONS 1–100
Question 1
A landscape contractor applies a pre-emergence herbicide to a bed of established daylilies in early March.
Which of the following best explains the primary mode of action of most pre-emergence herbicides used for
ornamental weed control?
A. Inhibition of photosynthetic electron transport
B. Disruption of cell membrane integrity via lipid peroxidation
C. Inhibition of root and shoot growth by disrupting cell division
D. Uncoupling of oxidative phosphorylation
🟢C
🔴 RATIONALE: Most pre-emergence herbicides (e.g., dithiopyr, pendimethalin, prodiamine) inhibit cell division
by disrupting microtubule assembly or inhibiting very-long-chain fatty acids, preventing seedling root and
shoot development.
Question 2
An applicator notices a dense patch of yellow nutsedge (Cyperus esculentus) in a container nursery. Which
herbicide mode of action is specifically effective against sedges while being safe around most established
woody ornamentals?
,A. EPSP synthase inhibitor (glyphosate)
B. Acetolactate synthase (ALS) inhibitor (halosulfuron)
C. Photosystem II inhibitor (atrazine)
D. Synthetic auxin (2,4-D)
🟢B
🔴 RATIONALE: Halosulfuron is an ALS inhibitor labeled for nutsedge control in ornamental nurseries; it is
absorbed through foliage and roots and selectively controls sedges without injuring many broadleaf
ornamentals.
Question 3
According to Ohio Administrative Code (OAC) 901:5-11, a commercial applicator applying a Restricted-Use
Pesticide (RUP) for ornamental weed control must:
A. Complete a WPS handler training every two years
B. Obtain a written prescription from a licensed veterinarian
C. Possess a valid Ohio Commercial Pesticide Applicator license with Category 6a
D. Notify all adjacent property owners 72 hours before application
🟢C
🔴 RATIONALE: OAC 901:5-11-03 requires that any person applying a restricted-use pesticide for hire must
hold the appropriate commercial applicator license category (here, 6a).
Question 4
Which of the following weed life cycles is most effectively managed by a fall-applied pre-emergence herbicide
in an ornamental planting bed?
, A. Summer annual broadleaf
B. Winter annual broadleaf
C. Perennial grass with rhizomes
D. Biennial thistle
🟢B
🔴 RATIONALE: Winter annuals (e.g., henbit, common chickweed, annual bluegrass) germinate in late summer
or fall. Fall pre-emergence application targets their emergence before winter dormancy.
Question 5
A certified applicator is calibrating a boomless sprayer for a landscape bed containing newly planted crabapple
trees. The label rate is 2 quarts per acre. The applicator covers a 1000 sq ft test area and catches 650 mL of
spray. The sprayer output is 20 gallons per minute, and ground speed is 3 mph. What is the first recommended
action?
A. Increase ground speed to 4 mph
B. Reduce nozzle orifice size
C. Recalculate based on actual measured output per 1000 sq ft
D. Add a drift reduction adjuvant
🟢C
🔴 RATIONALE: Calibration requires matching actual applied volume to target rate. The test catch shows
output; the applicator must compute gallons per 1000 sq ft and compare to label’s per-acre equivalent before
adjusting speed or nozzles.
Question 6
Which of the following best describes the Ohio Revised Code’s requirement for posting treated ornamental
