IOWA COMMERCIAL PESTICIDE APPL: RIGHT-OF-WAY
(CATEGORY 6) EXAM QUESTIONS AND ANSWERS COMPLETELY
VERIFIED
Who's Responsible?
An applicator is responsible for any damage to private or public property resulting from careless
application or misuse of herbicides
What are roadside management objectives?
The current goal of many roadside management programs is to 1) control only those plants listed as
noxious weeds or 2) plants that interfere with the vision of motorists, 3) inhibit the flow of water
through drainage ditches, 4) pose a fire hazard, or 5) interfere with activities of humans in other
manners. Spot treatments of problem areas, rather than broadcast applications, are commonly used
along roadsides.
What management techniques do counties use to maintain prairie vegetation on roadsides?
Counties integrate several different management techniques to maintain a strong, healthy plant
community. Techniques include 1) spot spraying perennial weeds, 2) mowing of annual & biennial weeds
to control seed production, and 3) periodic burning to recycle nutrients & increase plant diversity.
What are the most commonly used herbicides for roadside use?
The most commonly used herbicides for roadsides are postemergence chemicals that selectively control
herbaceous, broadleaf plants without injuring grasses
What types of herbicides are registered for use in rights-of-way?
The majority of these products are either growth regulator herbicides or ALS-inhibiting herbicides. These
herbicides are classified according to their mode of action, or how they kill plants.
List some common growth regulator herbicides
, Growth regulator herbicides include the 1) phenoxy products (2,4-D; 2,4-DP; and MCPP), 2) dicamba
(Banvel), 3) triclopyr (Garlon), 4) picloram (Tordon) and 5) clopyralid (Stinger). To broaden the spectrum
of control, these herbicides are often tank-mixed or formulated as products that contain more than one
active ingredient (e.g., Crossbow is a combination of 2,4-D and triclopyr. The specific combination used
should be based on weeds present, rather than indiscriminately adding herbicides to the spray tank.
What are some characteristics of growth regulator herbicides?
Most of these herbicides are rapidly degraded in the soil; thus, they provide little residual control. Only
weeds that are established at the time of application will be controlled. All of the growth regulator
herbicides are translocated within the plant, making them effective for both annual & perennial weeds.
List some common ALS-inhibiting herbicides
ALS is an enzyme involved in the synthesis of specific amino acids in plants. 1) Sulfrometuron (Oust) and
2) chlorsulfuron (Telar) are the most common ALS-inhibitors used on roadsides for broadleaf control.
Certain perennial grasses, including tall fescue & smooth brome, have a relatively low tolerance to these
chemicals & may be injured under certain conditions, follow label rates carefully. Plateau (Imazapic) and
Journey (Imazapic & glyphosate) are other ALS-inhibitors; Plateau is unique in that it is safe to use on
native grass & wildflower plantings.
What are the best times for applications?
Generally , herbicides are most effective when applied to actively growing plants, applications should be
avoided during hot, dry periods of midsummer.
ANNUAL weeds, such as velvetleaf & pigweed, are easiest to control early in the spring while they are
still small.
Musk thistle, common mullen, & other BIENNIALS should be treated in the fall or early spring while they
are still in the rosette stage. Biennials become fairly tolerant to most herbicides once the flower stalk
begins to elongate.
Optimum control of PERENNIALS, such as Canada thistle & field bindweed, can often be achieved with
applications made while the plant is in early bloom. Two applications of a herbicide may be required to
provide effective control of some perennials.
Why should you be especially careful treating roadsides with selective herbicides?
(CATEGORY 6) EXAM QUESTIONS AND ANSWERS COMPLETELY
VERIFIED
Who's Responsible?
An applicator is responsible for any damage to private or public property resulting from careless
application or misuse of herbicides
What are roadside management objectives?
The current goal of many roadside management programs is to 1) control only those plants listed as
noxious weeds or 2) plants that interfere with the vision of motorists, 3) inhibit the flow of water
through drainage ditches, 4) pose a fire hazard, or 5) interfere with activities of humans in other
manners. Spot treatments of problem areas, rather than broadcast applications, are commonly used
along roadsides.
What management techniques do counties use to maintain prairie vegetation on roadsides?
Counties integrate several different management techniques to maintain a strong, healthy plant
community. Techniques include 1) spot spraying perennial weeds, 2) mowing of annual & biennial weeds
to control seed production, and 3) periodic burning to recycle nutrients & increase plant diversity.
What are the most commonly used herbicides for roadside use?
The most commonly used herbicides for roadsides are postemergence chemicals that selectively control
herbaceous, broadleaf plants without injuring grasses
What types of herbicides are registered for use in rights-of-way?
The majority of these products are either growth regulator herbicides or ALS-inhibiting herbicides. These
herbicides are classified according to their mode of action, or how they kill plants.
List some common growth regulator herbicides
, Growth regulator herbicides include the 1) phenoxy products (2,4-D; 2,4-DP; and MCPP), 2) dicamba
(Banvel), 3) triclopyr (Garlon), 4) picloram (Tordon) and 5) clopyralid (Stinger). To broaden the spectrum
of control, these herbicides are often tank-mixed or formulated as products that contain more than one
active ingredient (e.g., Crossbow is a combination of 2,4-D and triclopyr. The specific combination used
should be based on weeds present, rather than indiscriminately adding herbicides to the spray tank.
What are some characteristics of growth regulator herbicides?
Most of these herbicides are rapidly degraded in the soil; thus, they provide little residual control. Only
weeds that are established at the time of application will be controlled. All of the growth regulator
herbicides are translocated within the plant, making them effective for both annual & perennial weeds.
List some common ALS-inhibiting herbicides
ALS is an enzyme involved in the synthesis of specific amino acids in plants. 1) Sulfrometuron (Oust) and
2) chlorsulfuron (Telar) are the most common ALS-inhibitors used on roadsides for broadleaf control.
Certain perennial grasses, including tall fescue & smooth brome, have a relatively low tolerance to these
chemicals & may be injured under certain conditions, follow label rates carefully. Plateau (Imazapic) and
Journey (Imazapic & glyphosate) are other ALS-inhibitors; Plateau is unique in that it is safe to use on
native grass & wildflower plantings.
What are the best times for applications?
Generally , herbicides are most effective when applied to actively growing plants, applications should be
avoided during hot, dry periods of midsummer.
ANNUAL weeds, such as velvetleaf & pigweed, are easiest to control early in the spring while they are
still small.
Musk thistle, common mullen, & other BIENNIALS should be treated in the fall or early spring while they
are still in the rosette stage. Biennials become fairly tolerant to most herbicides once the flower stalk
begins to elongate.
Optimum control of PERENNIALS, such as Canada thistle & field bindweed, can often be achieved with
applications made while the plant is in early bloom. Two applications of a herbicide may be required to
provide effective control of some perennials.
Why should you be especially careful treating roadsides with selective herbicides?
