Resistant Weed Quiz

 Answers to the Quiz will be posted later this week. Good luck!

What is the definition of herbicide resistance?

    1. The incremental tolerance of a weed population to a herbicide with each generation, eventually leading to resistance.
    2. The failure of a herbicide to kill a plant.
    3. The inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type.

 

Research shows (Bill Johnson, Purdue University) that the prevalence of glyphosate-tolerant giant ragweed is highly correlated to the management and use of glyphosate.

    1. True
    2. False

Common lambsquarters has been officially confirmed resistant to glyphosate in Wisconsin.

    1. True
    2. False

 

Which state is home to tri-resistant waterhemp (ALS, PS II, PPO)?

    1. Illinois
    2. Indiana
    3. Iowa
    4. Minnesota

 

According to speculation based on university research which glyphosate-resistant weed could be the biggest threat to the cotton industry since the boll weevil?

    1. Johnsongrass
    2. Marestail (horseweed)
    3. Velvetleaf
    4. Palmer pigweed

 

Which weed has become more prevalent in recent years due to the widespread use of glyphosate-tolerant corn?

    1. Waterhemp
    2. Volunteer corn
    3. Giant ragweed

 

When is the ideal time to apply glyphosate?

    1. When weeds are large, since glyphosate can control large weeds.
    2. Doesn't matter what size the weeds are, glyphosate should be applied in early June.
    3. When weeds are no larger than 4 to 6 inches tall.

 

Name this glyphosate-resistant weed found in Iowa.

Is it:

    1. Marestail (horseweed)
    2. Johnsongrass
    3. Waterhemp
    4. Common lambsquarters

 

Which of the following are good management practices to use on your fields?

    1. Scouting
    2. Alternating herbicide modes of action
    3. Using a pre-emergence residual herbicide
    4. Apply glyphosate to the proper weed size
    5. All of the above.

 

Researchers estimate that about which percent of the weed population is resistant by the time growers recognize it in the field?

    1. 10 percent
    2. 20 percent
    3. 30 percent
    4. 50 percent

 

Glyphosate-tolerant giant ragweed in Minnesota.

 

Palmer pigweed in cotton.

Published Wednesday, January 07, 2009 12:02 PM by Chuck Foresman

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