Iowa Herbicide Right of Way - Category 6 questions and
answers 2026\2027 A+ Grade
in early spring when sod has greened
- correct answer Growth regulator application is most effective when applied:
A. in early spring when sod has greened
B. in late spring when sod has grown at least 2"
C. after 3 times mowing
D. in fall just prior to leaf fall
Both B and C
- correct answer Which procedures will help reduce herbicide drift?
A. Increasing spray pressure
B. Reducing spray pressure
C. Hanging nozzles to a type which emits larger droplets
D. Reducing height of boom
E. Both B and C
They do not damage grasses
- correct answer Phenoxy herbicides are widely used along roadsides because:
A. They are effective on a wide variety of broadleaf and woody species
B. They rarely damage plants in adjacent areas
C. They are high in human toxicity
D. They do not damage grasses
E. Both A and D
,Dichlobenil
- correct answer Which of the following nonselective herbicides has the longest period of control, when
used at a given site:
A. Bromacil
B. Dichlobenil
C. Prometon
D. Tebuthiuron
During early flowering
- correct answer When is the best time to treat many perennials developing from an established root
system?
Outside an area equal to twice the height of the desirable trees
- correct answer In order to avoid injury to nearby desirable trees; persistent, nonselective herbicides
such as Hyvar should be applied:
A. Only in the fall
B. Outside the drip line of the desirable trees
C. At least 10 feet from the desirable trees
D. Outside an area equal to twice the height of the desirable trees
E. A minimum of 1/2 mile from the desirable trees
The bark prevents penetration of the herbicide and reduces effectiveness
- correct answer Basal bark treatment is not recommended for wood species larger than 6" in diameter
because:
A. The bark prevents penetration of the herbicide and reduces effectiveness
B. The cost is prohibitive
C. There is a high risk of drift
D. None of the above
They can damage desirable plants at very low rates, making them susceptible to drift damage
- correct answer A major disadvantage of the phenoxy-herbicides is:
A. They are non-selective herbicides
, B. They can damage desirable plants at very low rates, making them susceptible to drift damage
C. They are highly toxic to wildlife
D. They persist in the soil for several years
Little effect is seen the year of application
- correct answer Krenite is different from most brush herbicides because:
A. It can be applied either to the foliage or the soil
B. Little effect is seen the year of application
C. Both A and B
D. None of the above
Wettable powders
- correct answer Which of the following formulations do not dissolve in water?
A. Wettable powders
B. Soluble powders
C. Emulsifiable concentrate
D. All of the above dissolve in water
10
- correct answer Herbicide spraying can be performed, as a general rule, until wind speed exceeds ___
miles per hour.
Leaching
- correct answer The downward movements of pesticides in the soil is called _____.
Perennial
- correct answer Which type of weed is best controlled in early bloom?
A. Annual
B. Biennial
C. Perennial
D. Herbaceous
answers 2026\2027 A+ Grade
in early spring when sod has greened
- correct answer Growth regulator application is most effective when applied:
A. in early spring when sod has greened
B. in late spring when sod has grown at least 2"
C. after 3 times mowing
D. in fall just prior to leaf fall
Both B and C
- correct answer Which procedures will help reduce herbicide drift?
A. Increasing spray pressure
B. Reducing spray pressure
C. Hanging nozzles to a type which emits larger droplets
D. Reducing height of boom
E. Both B and C
They do not damage grasses
- correct answer Phenoxy herbicides are widely used along roadsides because:
A. They are effective on a wide variety of broadleaf and woody species
B. They rarely damage plants in adjacent areas
C. They are high in human toxicity
D. They do not damage grasses
E. Both A and D
,Dichlobenil
- correct answer Which of the following nonselective herbicides has the longest period of control, when
used at a given site:
A. Bromacil
B. Dichlobenil
C. Prometon
D. Tebuthiuron
During early flowering
- correct answer When is the best time to treat many perennials developing from an established root
system?
Outside an area equal to twice the height of the desirable trees
- correct answer In order to avoid injury to nearby desirable trees; persistent, nonselective herbicides
such as Hyvar should be applied:
A. Only in the fall
B. Outside the drip line of the desirable trees
C. At least 10 feet from the desirable trees
D. Outside an area equal to twice the height of the desirable trees
E. A minimum of 1/2 mile from the desirable trees
The bark prevents penetration of the herbicide and reduces effectiveness
- correct answer Basal bark treatment is not recommended for wood species larger than 6" in diameter
because:
A. The bark prevents penetration of the herbicide and reduces effectiveness
B. The cost is prohibitive
C. There is a high risk of drift
D. None of the above
They can damage desirable plants at very low rates, making them susceptible to drift damage
- correct answer A major disadvantage of the phenoxy-herbicides is:
A. They are non-selective herbicides
, B. They can damage desirable plants at very low rates, making them susceptible to drift damage
C. They are highly toxic to wildlife
D. They persist in the soil for several years
Little effect is seen the year of application
- correct answer Krenite is different from most brush herbicides because:
A. It can be applied either to the foliage or the soil
B. Little effect is seen the year of application
C. Both A and B
D. None of the above
Wettable powders
- correct answer Which of the following formulations do not dissolve in water?
A. Wettable powders
B. Soluble powders
C. Emulsifiable concentrate
D. All of the above dissolve in water
10
- correct answer Herbicide spraying can be performed, as a general rule, until wind speed exceeds ___
miles per hour.
Leaching
- correct answer The downward movements of pesticides in the soil is called _____.
Perennial
- correct answer Which type of weed is best controlled in early bloom?
A. Annual
B. Biennial
C. Perennial
D. Herbaceous
