Iowa Commercial Pesticide Applicator Category 1A Exam Well Solved

Iowa Commercial Pesticide Applicator Category 1A Exam Well Solved What is the greatest hazard when applying most herbicides? ANS-Injury to nontarget plants Name some herbicides which are very effective against germinating weeds but less effective on established weeds. ANS-Frontier, Lasso, and Dual What soil conditions reduce the activity of many herbicides and require increased rates for adequate weed control? ANS-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 ANS-Sencor and Lexone Where are high pH soils most common in Iowa? ANS-Next to limestone and gravel roads Two herbicides that are more persistent and likely to carryover residues. ANS-Atrazine and chlorimuron What factors can increase chances of herbicide carryover? ANS-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? ANS-Yes What do preemergence herbicides rely on to move the herbicide into the weed seed germination zone (top 1/2-1 inch) of soil? ANS-Rainfall or irrigation What tillage tools will improve weed control when rainfall does not occur soon after herbicide application, and weeds begin emerging? ANS-Rotary Hoe and Harrow Name 3 herbicides which must be incorporated to prevent evaporation loss. ANS-Sultan+, Eradicane, Eradicane Extra Define photodecomposition ANS-Chemical breakdown caused by exposure to light Name two herbicides that must be incorporated to prevent photodecomposition. ANS-Treflan, Sonalan