Iowa Commercial Pesticide Applicator
Category 1A Questions & Answers
1.What is the greatest hazard when applying most herbicides?
Answer Injury to non- target plants
2.Name some herbicides which are very effective against germinating
weeds but less effective on established weeds.
Answer Frontier, Lasso, and Dual
3.What soil conditions reduce the activity of many herbicides and require
increased rates for adequate weed control?
Answer Higher levels of soil organic matter or clay
4.Two herbicides which are more active on soils with a pH above 7.5 and
can injure soybeans
Answer Sencor and Lexone
5.Where are high pH soils most common in Iowa?
Answer Next to limestone and gravel roads
6.Two herbicides that are more persistent and likely to carryover residues.
Answer -
Atrazine and chlorimuron
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, 7.What factors can increase chances of herbicide carryover?
Answer Dry weather, high rates, late application, and in the case of
some herbicides, high soil pH
8.Can additive injury occur when applying Sencor/Lexone on soybeans
in fields with atrazine carryover residues?
Answer Yes
9.What do preemergence herbicides rely on to move the herbicide into
the weed seed germination zone (top 1/2-1 inch) of soil?
Answer Rainfall or irrigation
10.What tillage tools will improve weed control when rainfall does not occur
soon after herbicide application, and weeds begin emerging?
Answer Rotary Hoe and Harrow
11.Name 3 herbicides which must be incorporated to prevent
evaporation loss.
Answer Sultan+, Eradicane, Eradicane Extra
12.Define photodecomposition
Answer Chemical breakdown caused by exposure to light
13.Name two herbicides that must be incorporated to prevent
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Category 1A Questions & Answers
1.What is the greatest hazard when applying most herbicides?
Answer Injury to non- target plants
2.Name some herbicides which are very effective against germinating
weeds but less effective on established weeds.
Answer Frontier, Lasso, and Dual
3.What soil conditions reduce the activity of many herbicides and require
increased rates for adequate weed control?
Answer Higher levels of soil organic matter or clay
4.Two herbicides which are more active on soils with a pH above 7.5 and
can injure soybeans
Answer Sencor and Lexone
5.Where are high pH soils most common in Iowa?
Answer Next to limestone and gravel roads
6.Two herbicides that are more persistent and likely to carryover residues.
Answer -
Atrazine and chlorimuron
1/
8
, 7.What factors can increase chances of herbicide carryover?
Answer Dry weather, high rates, late application, and in the case of
some herbicides, high soil pH
8.Can additive injury occur when applying Sencor/Lexone on soybeans
in fields with atrazine carryover residues?
Answer Yes
9.What do preemergence herbicides rely on to move the herbicide into
the weed seed germination zone (top 1/2-1 inch) of soil?
Answer Rainfall or irrigation
10.What tillage tools will improve weed control when rainfall does not occur
soon after herbicide application, and weeds begin emerging?
Answer Rotary Hoe and Harrow
11.Name 3 herbicides which must be incorporated to prevent
evaporation loss.
Answer Sultan+, Eradicane, Eradicane Extra
12.Define photodecomposition
Answer Chemical breakdown caused by exposure to light
13.Name two herbicides that must be incorporated to prevent
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8
