Ohio Pesticide Applicator Certification: Category 6a – Ornamental
Weed Control Most Recent exam COMPLETE (2026) EXAM
Questions and Answers (Verified Answers) (Latest Update 2026)
1. Which of the following is a common perennial broadleaf weed in ornamental beds?
A. Crabgrass
B. Dandelion
C. Goosegrass
D. Annual bluegrass
Rationale: Dandelions are perennial broadleaf weeds that commonly invade lawns and
ornamental beds.
2. What type of weed completes its life cycle in one year?
A. Annual
B. Biennial
C. Perennial
D. Woody
Rationale: Annual weeds germinate, grow, reproduce, and die in one growing season.
3. Which weed spreads primarily by rhizomes?
A. White clover
B. Bermuda grass
C. Lambsquarters
D. Pigweed
Rationale: Bermuda grass spreads aggressively through underground rhizomes.
4. Biennial weeds typically flower in which year?
A. First year
B. Second year
C. Third year
D. Fourth year
Rationale: Biennials grow vegetatively in the first year and flower/seed in the second.
5. Which weed is an example of a monocot?
A. Crabgrass
B. Dandelion
C. Clover
D. Chickweed
Rationale: Crabgrass is a grass (monocot), while the others are broadleaf (dicots).
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,6. What part of a weed allows it to survive winter and regrow?
A. Seed
B. Rootstock or rhizome
C. Flower
D. Stem
Rationale: Perennial weeds survive adverse conditions via underground structures like rhizomes
or tubers.
7. Which weed reproduces primarily through seeds?
A. Chickweed
B. Bermuda grass
C. Quackgrass
D. Nutgrass
Rationale: Chickweed spreads mainly through prolific seed production.
8. What term describes weeds growing in areas where they are not wanted?
A. Pest
B. Weed
C. Pathogen
D. Fertilizer
Rationale: A weed is any plant growing where it is undesired.
9. Which factor is most important in weed seed germination?
A. Sunlight
B. Water
C. Insects
D. Fertilizer
Rationale: Adequate moisture is critical for most weed seeds to germinate.
10. Which of the following is an invasive ornamental weed?
A. Japanese knotweed
B. Crabgrass
C. Chickweed
D. Foxtail
Rationale: Japanese knotweed is non-native and aggressively spreads, making it invasive.
11–30: Herbicide Types & Selectivity
11. A selective herbicide:
A. Kills all plants
B. Targets specific plant types
2
C. Kills only insects
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,D. Improves soil fertility
Rationale: Selective herbicides control certain weeds without harming desirable plants.
12. Which herbicide type kills all vegetation it contacts?
A. Selective
B. Nonselective
C. Preemergent
D. Postemergent
Rationale: Nonselective herbicides like glyphosate kill most plants they contact.
13. Preemergent herbicides are applied:
A. After weed emergence
B. Before weed emergence
C. Only to perennials
D. Only to trees
Rationale: Preemergent herbicides prevent germination of seeds.
14. Which herbicide is systemic?
A. Vinegar
B. Glyphosate
C. Soap-based herbicide
D. Corn gluten meal
Rationale: Systemic herbicides move through the plant to kill roots and shoots.
15. Contact herbicides:
A. Move through the plant
B. Kill only the tissue they touch
C. Are applied before seed germination
D. Are selective to grasses
Rationale: Contact herbicides kill only the parts of the plant they contact.
16. Postemergent herbicides:
A. Are applied to soil
B. Target actively growing weeds
C. Are always selective
D. Are applied before seeds germinate
Rationale: Postemergent herbicides are used on emerged weeds.
17. Which factor affects herbicide uptake?
A. Soil type
B. Weather
C. Leaf surface
D. All of the above
Rationale: Uptake depends on multiple factors including leaf cuticle, soil, and environmental
3
conditions.
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, 18. Which herbicide label statement indicates selective use?
A. “Kills all vegetation”
B. “Use on broadleaf weeds only”
C. “Apply to soil only”
D. “Apply with gloves”
Rationale: Selective herbicides specify target plant types.
19. Glyphosate is classified as:
A. Preemergent
B. Systemic, nonselective
C. Contact, selective
D. Soil fumigant
Rationale: Glyphosate moves throughout the plant and kills most plants it contacts.
20. Which herbicide would you use to control crabgrass in an ornamental bed?
A. Postemergent grass-selective
B. Nonselective contact
C. Fungicide
D. Insecticide
Rationale: Grass-selective postemergent herbicides kill crabgrass without harming broadleaf
ornamentals.
21. Herbicide mode of action refers to:
A. Chemical structure
B. How it kills or injures the plant
C. Application timing
D. Label requirements
Rationale: Mode of action is the biochemical pathway affected in the plant.
22. Contact herbicides are most effective on:
A. Small, young weeds
B. Large, mature weeds
C. Underground roots
D. Seeds in soil
Rationale: Contact herbicides act where they touch, so young plants are more susceptible.
23. Which herbicide type is applied to prevent weed germination?
A. Systemic
B. Postemergent
C. Preemergent
D. Contact
Rationale: Preemergent herbicides inhibit germination of weed seeds.
24. Which factor improves herbicide absorption?
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A. Rain immediately after application
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Weed Control Most Recent exam COMPLETE (2026) EXAM
Questions and Answers (Verified Answers) (Latest Update 2026)
1. Which of the following is a common perennial broadleaf weed in ornamental beds?
A. Crabgrass
B. Dandelion
C. Goosegrass
D. Annual bluegrass
Rationale: Dandelions are perennial broadleaf weeds that commonly invade lawns and
ornamental beds.
2. What type of weed completes its life cycle in one year?
A. Annual
B. Biennial
C. Perennial
D. Woody
Rationale: Annual weeds germinate, grow, reproduce, and die in one growing season.
3. Which weed spreads primarily by rhizomes?
A. White clover
B. Bermuda grass
C. Lambsquarters
D. Pigweed
Rationale: Bermuda grass spreads aggressively through underground rhizomes.
4. Biennial weeds typically flower in which year?
A. First year
B. Second year
C. Third year
D. Fourth year
Rationale: Biennials grow vegetatively in the first year and flower/seed in the second.
5. Which weed is an example of a monocot?
A. Crabgrass
B. Dandelion
C. Clover
D. Chickweed
Rationale: Crabgrass is a grass (monocot), while the others are broadleaf (dicots).
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,6. What part of a weed allows it to survive winter and regrow?
A. Seed
B. Rootstock or rhizome
C. Flower
D. Stem
Rationale: Perennial weeds survive adverse conditions via underground structures like rhizomes
or tubers.
7. Which weed reproduces primarily through seeds?
A. Chickweed
B. Bermuda grass
C. Quackgrass
D. Nutgrass
Rationale: Chickweed spreads mainly through prolific seed production.
8. What term describes weeds growing in areas where they are not wanted?
A. Pest
B. Weed
C. Pathogen
D. Fertilizer
Rationale: A weed is any plant growing where it is undesired.
9. Which factor is most important in weed seed germination?
A. Sunlight
B. Water
C. Insects
D. Fertilizer
Rationale: Adequate moisture is critical for most weed seeds to germinate.
10. Which of the following is an invasive ornamental weed?
A. Japanese knotweed
B. Crabgrass
C. Chickweed
D. Foxtail
Rationale: Japanese knotweed is non-native and aggressively spreads, making it invasive.
11–30: Herbicide Types & Selectivity
11. A selective herbicide:
A. Kills all plants
B. Targets specific plant types
2
C. Kills only insects
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EXAMPREPMASTER
,D. Improves soil fertility
Rationale: Selective herbicides control certain weeds without harming desirable plants.
12. Which herbicide type kills all vegetation it contacts?
A. Selective
B. Nonselective
C. Preemergent
D. Postemergent
Rationale: Nonselective herbicides like glyphosate kill most plants they contact.
13. Preemergent herbicides are applied:
A. After weed emergence
B. Before weed emergence
C. Only to perennials
D. Only to trees
Rationale: Preemergent herbicides prevent germination of seeds.
14. Which herbicide is systemic?
A. Vinegar
B. Glyphosate
C. Soap-based herbicide
D. Corn gluten meal
Rationale: Systemic herbicides move through the plant to kill roots and shoots.
15. Contact herbicides:
A. Move through the plant
B. Kill only the tissue they touch
C. Are applied before seed germination
D. Are selective to grasses
Rationale: Contact herbicides kill only the parts of the plant they contact.
16. Postemergent herbicides:
A. Are applied to soil
B. Target actively growing weeds
C. Are always selective
D. Are applied before seeds germinate
Rationale: Postemergent herbicides are used on emerged weeds.
17. Which factor affects herbicide uptake?
A. Soil type
B. Weather
C. Leaf surface
D. All of the above
Rationale: Uptake depends on multiple factors including leaf cuticle, soil, and environmental
3
conditions.
Page
EXAMPREPMASTER
, 18. Which herbicide label statement indicates selective use?
A. “Kills all vegetation”
B. “Use on broadleaf weeds only”
C. “Apply to soil only”
D. “Apply with gloves”
Rationale: Selective herbicides specify target plant types.
19. Glyphosate is classified as:
A. Preemergent
B. Systemic, nonselective
C. Contact, selective
D. Soil fumigant
Rationale: Glyphosate moves throughout the plant and kills most plants it contacts.
20. Which herbicide would you use to control crabgrass in an ornamental bed?
A. Postemergent grass-selective
B. Nonselective contact
C. Fungicide
D. Insecticide
Rationale: Grass-selective postemergent herbicides kill crabgrass without harming broadleaf
ornamentals.
21. Herbicide mode of action refers to:
A. Chemical structure
B. How it kills or injures the plant
C. Application timing
D. Label requirements
Rationale: Mode of action is the biochemical pathway affected in the plant.
22. Contact herbicides are most effective on:
A. Small, young weeds
B. Large, mature weeds
C. Underground roots
D. Seeds in soil
Rationale: Contact herbicides act where they touch, so young plants are more susceptible.
23. Which herbicide type is applied to prevent weed germination?
A. Systemic
B. Postemergent
C. Preemergent
D. Contact
Rationale: Preemergent herbicides inhibit germination of weed seeds.
24. Which factor improves herbicide absorption?
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A. Rain immediately after application
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