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Ohio Commercial Pesticide Applicator Category 6c
– Ornamental Weed Pest Control Exam COMPLETE
QUESTIONS AND DETAILED SOLUTIONS LATEST
UPDATE THIS YEAR-JUST RELEASED
Ohio Commercial Pesticide Applicator Category 6c – Ornamental Weed Pest Control Exam, based on
Ohio regulations (OAC 901:5-11) and standard weed science principles for nurseries, greenhouses,
landscapes, and managed turf adjacent to ornamentals.
SUMMARIZED EXAM COVERAGE (Point Form – High Relevance for Actual Exam)
• Ornamental Weed Identification: Grasses (crabgrass, goosegrass, foxtail), broadleaves
(dandelion, clover, plantain, oxalis, ground ivy, spurge, henbit, chickweed), sedges (yellow
nutsedge, green kyllinga), and woody/invasive perennials (poison ivy, multiflora rose, bush
honeysuckle).
• Herbicide Classification – Sites of Action: WSSA numeric groups (Groups 1–34); understanding
resistance management (e.g., Group 2 (ALS), Group 3 (microtubule), Group 4 (synthetic auxin),
Group 5 (photosystem II), Group 9 (EPSP synthase – glyphosate), Group 14 (PPO), Group 22
(PSI), Group 27 (HPPD).
• Herbicide Selectivity & Application Timing: Pre-emergence vs. post-emergence; soil-residual vs.
contact/translocated; labeling for "ornamental" sites only (not food crops); overseeding
restrictions.
• Application Methods: Granular vs. sprayable; shielded sprayers for over-the-top use; spot
treatment; wiper applicators; calibration (GPA, MPH, nozzle selection).
• Weed Control in Specific Sites: Nurseries (container vs. field-grown), greenhouses (no volatile
herbicides under glass), landscapes (mulch + herbicide combinations), rights-of-way around
ornamentals.
• Non-Chemical Control: Mulching, hand-weeding, cultivation, flame weeding (with care),
irrigation management.
• Phytotoxicity Prevention: Drift to non-target ornamentals; root uptake from soil residuals;
temperature inversions; sensitive species (maples, dogwoods, hydrangeas, roses).
• Environmental Protection: Ohio’s sensitive crop registry; surface water buffers; groundwater
protection (label language); endangered species restrictions.
• PPE & Safety: Labels specify minimum PPE; mixing/loading precautions; decontamination; heat
stress.
• Laws & Regulations: Ohio’s pesticide law does not have a grace period (OAC 901:5-11-07);
recordkeeping required for all commercial applications (3 years); Category 6c specifically for
ornamental weed control (turf excluded except where mixed with ornamentals).
• Invasive & Noxious Weeds (Ohio): Poison hemlock, wild parsnip, Japanese knotweed, purple
loosestrife (wetlands), tree-of-heaven (spotted lanternfly host).
1. A nursery grower applies a pre-emergence herbicide labeled for container ornamentals. Two weeks
later, weeds are still emerging. Which is the most likely cause?
, Page 2 of 155
A) Herbicide was applied after weed seeds had already germinated
B) The herbicide was mixed at double the label rate
C) The herbicide was a post-emergence product
D) The soil temperature was below 40°F during application
Answer: A
Rationale: Pre-emergence herbicides must be applied before weed seeds germinate; if seeds have
already emerged, the herbicide will not control them.
2. You are treating landscaped beds with a non-selective post-emergence herbicide around established
hydrangeas. Which application method minimizes phytotoxicity?
A) Over-the-top broadcast spray
B) Shielded spray directed at weed foliage only, avoiding contact with ornamentals
C) Granular application followed by irrigation
D) High-pressure spray aimed at weeds
, Page 3 of 155
Answer: B
Rationale: Shielded spray physically blocks herbicide from contacting desirable plants, preventing drift or
direct contact injury.
3. Which weed is a perennial broadleaf commonly found in Ohio ornamental beds that reproduces by
both seeds and creeping stolons?
A) Crabgrass
B) Yellow nutsedge
C) Ground ivy (creeping Charlie)
D) Annual bluegrass
Answer: C
Rationale: Ground ivy is a perennial broadleaf with creeping stolons; it spreads aggressively in shaded,
moist ornamental beds.
4. A label for an ornamental bed pre-emergence herbicide reads “Do not apply to newly transplanted
ornamentals until soil has settled.” Why is this precaution important?
A) New transplants are too expensive to risk
, Page 4 of 155
B) Settled soil prevents herbicide from washing into root zone and injuring tender roots
C) The herbicide only works on compacted soil
D) New transplants repel herbicides
Answer: B
Rationale: Unsettled soil has large pores and cracks that allow herbicide to reach root systems of newly
planted ornamentals, causing injury.
5. A landscaper applies glyphosate to control poison ivy growing up a chain-link fence adjacent to a rose
garden on a calm morning. Two days later, roses show leaf curling. The most likely cause is:
A) The glyphosate was mixed too strong
B) Glyphosate vapor drift from the poison ivy leaves
C) The roses were overwatered
D) A fungal disease appeared simultaneously
Answer: B
Rationale: Glyphosate has very low volatility, but under warm conditions, fine droplets or particles can
drift as vapor or aerosol; roses are extremely sensitive.
Ohio Commercial Pesticide Applicator Category 6c
– Ornamental Weed Pest Control Exam COMPLETE
QUESTIONS AND DETAILED SOLUTIONS LATEST
UPDATE THIS YEAR-JUST RELEASED
Ohio Commercial Pesticide Applicator Category 6c – Ornamental Weed Pest Control Exam, based on
Ohio regulations (OAC 901:5-11) and standard weed science principles for nurseries, greenhouses,
landscapes, and managed turf adjacent to ornamentals.
SUMMARIZED EXAM COVERAGE (Point Form – High Relevance for Actual Exam)
• Ornamental Weed Identification: Grasses (crabgrass, goosegrass, foxtail), broadleaves
(dandelion, clover, plantain, oxalis, ground ivy, spurge, henbit, chickweed), sedges (yellow
nutsedge, green kyllinga), and woody/invasive perennials (poison ivy, multiflora rose, bush
honeysuckle).
• Herbicide Classification – Sites of Action: WSSA numeric groups (Groups 1–34); understanding
resistance management (e.g., Group 2 (ALS), Group 3 (microtubule), Group 4 (synthetic auxin),
Group 5 (photosystem II), Group 9 (EPSP synthase – glyphosate), Group 14 (PPO), Group 22
(PSI), Group 27 (HPPD).
• Herbicide Selectivity & Application Timing: Pre-emergence vs. post-emergence; soil-residual vs.
contact/translocated; labeling for "ornamental" sites only (not food crops); overseeding
restrictions.
• Application Methods: Granular vs. sprayable; shielded sprayers for over-the-top use; spot
treatment; wiper applicators; calibration (GPA, MPH, nozzle selection).
• Weed Control in Specific Sites: Nurseries (container vs. field-grown), greenhouses (no volatile
herbicides under glass), landscapes (mulch + herbicide combinations), rights-of-way around
ornamentals.
• Non-Chemical Control: Mulching, hand-weeding, cultivation, flame weeding (with care),
irrigation management.
• Phytotoxicity Prevention: Drift to non-target ornamentals; root uptake from soil residuals;
temperature inversions; sensitive species (maples, dogwoods, hydrangeas, roses).
• Environmental Protection: Ohio’s sensitive crop registry; surface water buffers; groundwater
protection (label language); endangered species restrictions.
• PPE & Safety: Labels specify minimum PPE; mixing/loading precautions; decontamination; heat
stress.
• Laws & Regulations: Ohio’s pesticide law does not have a grace period (OAC 901:5-11-07);
recordkeeping required for all commercial applications (3 years); Category 6c specifically for
ornamental weed control (turf excluded except where mixed with ornamentals).
• Invasive & Noxious Weeds (Ohio): Poison hemlock, wild parsnip, Japanese knotweed, purple
loosestrife (wetlands), tree-of-heaven (spotted lanternfly host).
1. A nursery grower applies a pre-emergence herbicide labeled for container ornamentals. Two weeks
later, weeds are still emerging. Which is the most likely cause?
, Page 2 of 155
A) Herbicide was applied after weed seeds had already germinated
B) The herbicide was mixed at double the label rate
C) The herbicide was a post-emergence product
D) The soil temperature was below 40°F during application
Answer: A
Rationale: Pre-emergence herbicides must be applied before weed seeds germinate; if seeds have
already emerged, the herbicide will not control them.
2. You are treating landscaped beds with a non-selective post-emergence herbicide around established
hydrangeas. Which application method minimizes phytotoxicity?
A) Over-the-top broadcast spray
B) Shielded spray directed at weed foliage only, avoiding contact with ornamentals
C) Granular application followed by irrigation
D) High-pressure spray aimed at weeds
, Page 3 of 155
Answer: B
Rationale: Shielded spray physically blocks herbicide from contacting desirable plants, preventing drift or
direct contact injury.
3. Which weed is a perennial broadleaf commonly found in Ohio ornamental beds that reproduces by
both seeds and creeping stolons?
A) Crabgrass
B) Yellow nutsedge
C) Ground ivy (creeping Charlie)
D) Annual bluegrass
Answer: C
Rationale: Ground ivy is a perennial broadleaf with creeping stolons; it spreads aggressively in shaded,
moist ornamental beds.
4. A label for an ornamental bed pre-emergence herbicide reads “Do not apply to newly transplanted
ornamentals until soil has settled.” Why is this precaution important?
A) New transplants are too expensive to risk
, Page 4 of 155
B) Settled soil prevents herbicide from washing into root zone and injuring tender roots
C) The herbicide only works on compacted soil
D) New transplants repel herbicides
Answer: B
Rationale: Unsettled soil has large pores and cracks that allow herbicide to reach root systems of newly
planted ornamentals, causing injury.
5. A landscaper applies glyphosate to control poison ivy growing up a chain-link fence adjacent to a rose
garden on a calm morning. Two days later, roses show leaf curling. The most likely cause is:
A) The glyphosate was mixed too strong
B) Glyphosate vapor drift from the poison ivy leaves
C) The roses were overwatered
D) A fungal disease appeared simultaneously
Answer: B
Rationale: Glyphosate has very low volatility, but under warm conditions, fine droplets or particles can
drift as vapor or aerosol; roses are extremely sensitive.
