Module 8.2: Summative Assessment: Herbicide Resistant Weed Interpretation and Management of Multiple Pest Types

Instructions

Explore the International Survey of Herbicide Resistant Weeds: an answer the questions below.On theInternational Survey of Herbicide Resistant WeedsHome page, examine the trends of herbicide resistant weeds. In the left column chose "Summaries" by "US State Map" and by "Country". By moving your cursor over the states and scrolling down the list of countries, compare the number of herbicide resistant weed species across a range of geographical regions. You can also view the data in as a “Global Map”.

  1. Based on what you have learned about factors that contribute to weeds evolving resistance to herbicides, what might explain the number of herbicide resistant species and how they differ among world countries, regions, and states in the United States?
  1. Return to the left column and click on Glyphosate Resistant Weeds. Review the chronological list of weeds that have been identified as resistant to glyphosate, and where the resistance was reported in the United States. Examine the reports of resistance for the two annual weed species:Amaranthuspalmeri(Palmer amaranth) andConyzacanadensis(Horseweed). How might you describe the spatial and temporal trends of glyphosate resistance in the United States of these two annual weed species? Based on what you have learned about weed reproduction, glyphosate herbicide use, and industrial agricultural systems, discuss two to three factors that likely explain the spatial distribution and rate of evolution of glyphosate resistance in these weed species.
  1. In this module,you learned about thestackedtransgenic herbicide-resistancecrops thatMonsanto and Dow AgroSciences developedto control glyphosate-resistant weeds. In addition to glyphosate resistance, the stackedtransgenic herbicide-resistance soybeans and cottonhave resistanceto either dicamba or 2,4-D, herbicides that are volatile, and prone todrifting and damaging broadleaf plants outside of the location where they are sprayed. In 2017,dicamba-resistant crops were released in some states, and manyfarmers reported that dicambadrifted into theirfields and damaged their crops. Discuss at least two other potential problems withwide-scale adoption ofthese stacked herbicide resistant crops.
  1. Insects, weeds, and pathogens have evolved resistance to chemical control tacticsand insects totransgenic Bt crop traits. Describetwo specificpest control tactics other than chemical control tactics andthe transgenic Bt cropsthat a farmer whom grows grains crop such as corn and soybeanscould employ tocontrol insects, weeds and diseases. Explain how and whyIPM canreduce the risk of thepests evolving resistance.
  2. Submitting your Assignment

You should submit your answers in your course CMS, and bring your typed answers to this assessment to the following class.