Herbicide programs for control of a five-way herbicide resistant waterhemp population in Xtendflex or Enlist E3 soybean

1. What was the primary objective of this study?

a. Identify effective herbicide programs for controlling multiple-resistant waterhemp.
b. Compare irrigation system strategies for improving water use efficiency in row crops.
c. Evaluate nitrogen management practices for optimizing soybean growth and yield outcomes.
d. Study soybean planting date effects on emergence timing, development, and final yield performance.

2. The waterhemp population evaluated in this study was resistant to how many herbicide groups?

a. Three.
b. Four.
c. Five.
d. Six.

3. Which herbicide groups were included in the resistance profile of the waterhemp population?

a. Groups 1, 3, 7, 10, and 15.
b. Groups 2, 3, 6, 8, and 14.
c. Groups 2, 4, 5, 9, and 14.
d. Groups 4, 9, 10, 12, and 27.

4. Two soybean trait platforms were evaluated in this study. Which were they?

a. Roundup Ready and LibertyLink.
b. XtendFlex and Enlist E3.
c. Clearfield and LibertyLink.
d. Roundup Ready 2 and Xtend.

5. Soybean injury from POST herbicide applications exceeded 10% in at least one year of the study.

a. True.
b. False.

6. What was the general effect of two-pass herbicide programs compared with one-pass programs?

a. Reduced weed control compared with single-pass herbicide application programs.
b. No measurable difference in overall waterhemp control across treatment programs.
c. Increased crop injury without improving overall waterhemp control effectiveness.
d. Increased waterhemp control by at least 30%.

7. In 2021, which herbicide program strategy tended to be more effective?

a. PRE-only programs.
b. POST–POST programs.
c. Single POST applications.
d. No herbicide programs.

8. In 2022, which herbicide program strategy performed better?

a. POST-only programs.
b. Single-pass programs.
c. PRE–POST programs.
d. No difference among programs.

9. Which factor contributed to differences in herbicide performance between 2021 and 2022?

a. Hybrid maturity.
b. Soil texture.
c. Rainfall.
d. Row spacing.

10. Rainfall shortly after PRE application can influence herbicide activation and effectiveness.

a. True.
b. False

11. Which auxin herbicides were compared in the study?

a. Dicamba and 2,4-D.
b. Dicamba and atrazine.
c. Glufosinate and glyphosate.
d. Mesotrione and atrazine.

12. What trend was observed regarding dicamba performance in 2022?

a. It outperformed all other herbicides.
b. It had no activity.
c. It was less effective than 2,4-D.
d. It caused excessive crop injury.

13. There was a significant interaction between soybean variety and herbicide treatment on yield.

a. True. 
b. False.

14. What was the typical timing of the first POST application?

a. At planting.
b. Seven days after planting.
c. At flowering.
d. 28–29 days after planting.

15. Based on the study, what is the most effective strategy for managing multiple-resistant waterhemp?

a. Use a single POST herbicide application.
b. Rely on dicamba alone.
c. Avoid PRE herbicides.
d. Use two-pass herbicide programs that include 2,4-D tank mixed with glufosinate.

16. Which application timing combination defines a PRE–POST herbicide program?

a. Two applications after crop emergence.
b. One application at flowering and one at maturity.
c. One application before crop emergence followed by one after emergence.
d. Two applications before planting.

17. In addition to using two-pass herbicide programs, another best management practice (BMP) for controlling troublesome weeds includes

a. the use of herbicides from multiple effective mode of action groups.
b. the use of herbicides from the same mode of action group.
c. mowing.
d. spraying the same herbicide multiple times.

18. Which herbicide mode of action is associated with glufosinate, a key component in some treatments?

a. Group 2 (ALS inhibitor).
b. Group 4 (synthetic auxin).
c. Group 9 (EPSPS inhibitor).
d. Group 10 (glutamine synthetase inhibitor).

19. Which of the following best describes why multiple modes of action are recommended for managing herbicide-resistant waterhemp?

a. To reduce application costs.
b. To increase soybean yield potential directly.
c. To delay further resistance development and improve control.
d. To simplify herbicide programs.

20. What was a common characteristic of the most effective herbicide programs in this study?

a. Use of a single herbicide with high rate.
b. Reliance on glyphosate alone.
c. Inclusion of multiple effective herbicide sites of action applied in sequence.
d. Application only at late reproductive stages.
 

^{This quiz was drafted with AI assistance and reviewed by the editorial team for accuracy and appropriateness.}