Iowa Commercial Pesticide Applicator Category 1A Latest Update Graded A
Question : What is the greatest hazard when applying most
herbicides?
CORRECT ANSWER : Injury to nontarget plants
Question : Name some herbicides which are very effective
against germinating weeds but less effective on established weeds.
CORRECT ANSWER : Frontier, Lasso, and Dual
Question : 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
Question : Two herbicides which are more active on soils
with a pH above 7.5 and can injure soybeans
CORRECT ANSWER : Sencor and Lexone
Question : Where are high pH soils most common in Iowa?
CORRECT ANSWER : Next to limestone and gravel roads
Question : Two herbicides that are more persistent and likely
to carryover residues.
CORRECT ANSWER : Atrazine and chlorimuron
Question : 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
Question : Can additive injury occur when applying
Sencor/Lexone on soybeans in fields with atrazine carryover residues?
CORRECT ANSWER : Yes
Question : 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
Question : 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
Question : Name 3 herbicides which must be incorporated to
prevent evaporation loss.
CORRECT ANSWER : Sultan+, Eradicane, Eradicane Extra
Question : Define photodecomposition
CORRECT ANSWER : Chemical breakdown caused by
exposure to light
Question : Name two herbicides that must be incorporated to
prevent photodecomposition.
CORRECT ANSWER : Treflan, Sonalan
Question : Why are Basagran, Blazer, Buctril, Poast Plus, and
Fusilade 2000 only applied postemergence?
CORRECT ANSWER : They have little or no soil activity
Question : Are Roundup and Gramoxone Extra selective or
nonselective herbicides?
CORRECT ANSWER : Nonselective
Question : Are Blazer, Basagran, Buctril, and Gramoxone
Extra contact herbicides or translocated herbicides?
CORRECT ANSWER : Contact herbicides
Question : Define translocated herbicides
CORRECT ANSWER : Herbicides which move in the
phloem of plants
Question : Do translocated herbicides move up, down, or both
ways in plants?