Iowa Commercial Pesticide Applicator
Category 1A UPDATED ACTUAL Exam
Questions and CORECT Answers
What is the greatest hazard when applying most herbicides? - CORRECT ANSWER -
Injury to nontarget plants
Name some herbicides which are very effective against germinating weeds but less effective on
established weeds. - CORRECT ANSWER - Frontier, Lasso, and Dual
What soil conditions reduce the activity of many herbicides and require increased rates for
adequate weed control? - CORRECT ANSWER - Higher levels of soil organic matter or
clay
Two herbicides which are more active on soils with a pH above 7.5 and can injure soybeans -
CORRECT ANSWER - Sencor and Lexone
Where are high pH soils most common in Iowa? - CORRECT ANSWER - Next to
limestone and gravel roads
Two herbicides that are more persistent and likely to carryover residues. - CORRECT
ANSWER - Atrazine and chlorimuron
What factors can increase chances of herbicide carryover? - CORRECT ANSWER - Dry
weather, high rates, late application, and in the case of some herbicides, high soil pH
Can additive injury occur when applying Sencor/Lexone on soybeans in fields with atrazine
carryover residues? - CORRECT ANSWER - Yes
, What do preemergence herbicides rely on to move the herbicide into the weed seed germination
zone (top 1/2-1 inch) of soil? - CORRECT ANSWER - Rainfall or irrigation
What tillage tools will improve weed control when rainfall does not occur soon after herbicide
application, and weeds begin emerging? - CORRECT ANSWER - Rotary Hoe and Harrow
Name 3 herbicides which must be incorporated to prevent evaporation loss. - CORRECT
ANSWER - Sultan+, Eradicane, Eradicane Extra
Define photodecomposition - CORRECT ANSWER - Chemical breakdown caused by
exposure to light
Name two herbicides that must be incorporated to prevent photodecomposition. - CORRECT
ANSWER - Treflan, Sonalan
Why are Basagran, Blazer, Buctril, Poast Plus, and Fusilade 2000 only applied postemergence? -
CORRECT ANSWER - They have little or no soil activity
Are Roundup and Gramoxone Extra selective or nonselective herbicides? - CORRECT
ANSWER - Nonselective
Are Blazer, Basagran, Buctril, and Gramoxone Extra contact herbicides or translocated
herbicides? - CORRECT ANSWER - Contact herbicides
Define translocated herbicides - CORRECT ANSWER - Herbicides which move in the
phloem of plants
Do translocated herbicides move up, down, or both ways in plants? - CORRECT
ANSWER - Because translocated herbicides move within the phloem, they can move both
up and down a plant.
Category 1A UPDATED ACTUAL Exam
Questions and CORECT Answers
What is the greatest hazard when applying most herbicides? - CORRECT ANSWER -
Injury to nontarget plants
Name some herbicides which are very effective against germinating weeds but less effective on
established weeds. - CORRECT ANSWER - Frontier, Lasso, and Dual
What soil conditions reduce the activity of many herbicides and require increased rates for
adequate weed control? - CORRECT ANSWER - Higher levels of soil organic matter or
clay
Two herbicides which are more active on soils with a pH above 7.5 and can injure soybeans -
CORRECT ANSWER - Sencor and Lexone
Where are high pH soils most common in Iowa? - CORRECT ANSWER - Next to
limestone and gravel roads
Two herbicides that are more persistent and likely to carryover residues. - CORRECT
ANSWER - Atrazine and chlorimuron
What factors can increase chances of herbicide carryover? - CORRECT ANSWER - Dry
weather, high rates, late application, and in the case of some herbicides, high soil pH
Can additive injury occur when applying Sencor/Lexone on soybeans in fields with atrazine
carryover residues? - CORRECT ANSWER - Yes
, What do preemergence herbicides rely on to move the herbicide into the weed seed germination
zone (top 1/2-1 inch) of soil? - CORRECT ANSWER - Rainfall or irrigation
What tillage tools will improve weed control when rainfall does not occur soon after herbicide
application, and weeds begin emerging? - CORRECT ANSWER - Rotary Hoe and Harrow
Name 3 herbicides which must be incorporated to prevent evaporation loss. - CORRECT
ANSWER - Sultan+, Eradicane, Eradicane Extra
Define photodecomposition - CORRECT ANSWER - Chemical breakdown caused by
exposure to light
Name two herbicides that must be incorporated to prevent photodecomposition. - CORRECT
ANSWER - Treflan, Sonalan
Why are Basagran, Blazer, Buctril, Poast Plus, and Fusilade 2000 only applied postemergence? -
CORRECT ANSWER - They have little or no soil activity
Are Roundup and Gramoxone Extra selective or nonselective herbicides? - CORRECT
ANSWER - Nonselective
Are Blazer, Basagran, Buctril, and Gramoxone Extra contact herbicides or translocated
herbicides? - CORRECT ANSWER - Contact herbicides
Define translocated herbicides - CORRECT ANSWER - Herbicides which move in the
phloem of plants
Do translocated herbicides move up, down, or both ways in plants? - CORRECT
ANSWER - Because translocated herbicides move within the phloem, they can move both
up and down a plant.
