What’s Your Weed Resistance I.Q.?

How knowledgeable are you about weed resistance?  Take this short quiz and post your answers below. Check back tomorrow to see how well you did!

1.         Experts at the University of Illinois recently confirmed the first glyphosate-resistant weed in the state. What weed species did they identify?

A. Waterhemp

B. Horseweed

C. Common ragweed

2.         One U.S. state holds the sole title of being the only state with four weeds confirmed resistant to glyphosate. What state is it?

A. Arkansas

B. Missouri

C. Kansas

3.         Stacked resistance, or resistance to multiple herbicide chemistries, can wreak havoc for growers and limit control options even further. There are a few cases of weeds with stacked resistance that include glyphosate herbicides. Name one.

A. Glyphosate- and ALS-resistant marestail (horseweed) in Ohio

B. Glyphosate- and ALS-resistant waterhemp in Illinois

C. Glyphosate-, ALS- and PPO-resistant waterhemp in Missouri

D. Options A and B

E. All of the above

4.         Around the world, the number of unique cases of herbicide resistant weeds has dramatically increased over the last 20 years. What are the three most common modes of action for weeds to develop resistance to?

A. ALS inhibitors, ACCase inhibitors, glycines

B. ALS inhibitors, Photosystem II inhibitors, ACCase inhibitors

C. ACCase inhibitors, glycines, Photosystem II inhibitors

5.         What is the proper definition of herbicide resistance?

A. The incremental increase in tolerance of a weed population to a herbicide with

        each generation, eventually leading to resistance

B. The inherited ability of a plant to survive and reproduce following exposure to

        a dose of herbicide normally lethal to the wild type

C. The failure of a herbicide to kill a plant

6.         How many unique herbicide-resistant weed biotypes are there in the United States today?

A. 70+

B. 15+

C. 50+

7.         There are very few new herbicides being developed by chemical companies. To bring a new herbicide to market generally takes 10 years and $200 million. What were the last new modes of action developed for cereals, soybeans and corn (respectively)?

A. ALS inhibitors, Glufosinate, Glufosinate

B. ACCase inhibitors, Glufosinate, HPPD inhibitors

C. ALS inhibitors, Glufosinate, HPPD inhibitors

8.         What country has the worst problem with grass weed resistance in the world?

A. Australia

B. United States

C. Brazil

9.         How long has glyphosate been on the market? When was it first used intensively over-the-top of crops?

A. 30+, 1996

B. 5+, 2000

C. 10+, 1991

10.       Since the first case of glyphosate resistance was confirmed in 2000, how many states across the country have confirmed glyphosate resistance?

A. 17

B. 19

C. 12

11.       What can this picture tell us about possible resistance?

A. That there is possible resistance because the weed is not completely destroyed

B. That there is no possibility of resistance because the weed is dying

C. That there is possible resistance because there are dead weeds next to live ones

12.       Once a grower identifies resistant weeds in his field, what percent of the population typically has already developed resistance?

A. 30%

B. 2%

C. 65%

13.       Have you experienced weed resistance first-hand?  What did you do to combat it?

Good luck!  Need some hints?  Try these resources:

¨      www.weedscience.org

¨      http://www.plantprotection.org/HRAC/

¨      http://www.resistancefighter.com/library/default.aspx

¨      http://www.resistancefighter.com/about/default.aspx