1. It’s Time for Glyphosate Stewardship Can PSEP Help? Chris Boerboom Extension Weed Scientist University of Wisconsin-Madison

2. Glyphosate Technologies Burndown treatments in no-till

3. Glyphosate Technologies Glyphosate-resistant crops in-season glyphosate use Benefits Broad spectrum weed control Crop safety Rotational crop flexibility Environmentally favorable

4. What is Herbicide Resistance?

5. Confirmed Glyphosate Resistant Weeds in the US (2006) Horseweed (Marestail) Common Ragweed Italian Ryegrass Rigid Ryegrass Palmer Amaranth Common Waterhemp Giant Ragweed

6. Glyphosate Resistant Weeds in the US Rigid ryegrass Horseweed Italian ryegrass Common ragweed Waterhemp Palmer amaranth Giant ragweed

7. "Stupidity is doing the same thing over and over again expecting different results" ~ A. Einstein

8. Photo credit: Larry Steckel Horseweed or “Marestail”

9. 2004 Common Horseweed Burndown Program Photo credit: Larry Steckel

10. California: Glyphosate-resistant horseweed on a ditch-bank

11. Common Ragweed 96 oz/a WeatherMax York, NCSU

12. WeatherMax 22 oz, 2 d after application to 16 inch Palmer

13. WeatherMax 88 oz at 1 inch WeatherMax 88 oz at 4 inch WeatherMax 88 oz PDIR Culpepper, UG Palmer Amaranth

14. Prowl H20 1.75 pt + Reflex 1 pt PRE WeatherMax 22 oz + Dual Mag 18 DAP before Pigweed emergence WeatherMax 22 oz + Direx 1.5 pt PDIR Culpepper, UG

15. Distribution of Glyphosate-Resistant Palmer Amaranth Culpepper, UG

16. Herbicide Cost Needed To Manage Palmer Amaranth in Georgia and North Carolina Cotton Soybean Corn Sensitive Palmer $18 $8 $10 Resistant Palmer $42 $24 $14 Culpepper, UG

17. Johnson, PU “Giant” Ragweed

18. Sensitive Henry co. Suspect Noble co. Untreated 2.25 lb ae/A at 21 DAT Johnson, PU

19. To which herbicide has waterhemp NOT developed resistance? 1.Blazer 2.Pursuit 3.Glyphosate 4.Reflex 5.Classic

20. Resistance trait will move through pollen Culpepper, UG

22. Critical factors affecting the development of herbicide resistance Mutation rate for resistance traits Initial frequency of resistant weeds Herbicide selection intensity Inheritance of resistance traits Gene flow

23. 96 97 98 99 00 01 02 03 04 05 06 98 99 00 01 02 03 04 05 06 97 98 99 00 01 02 03 04 05 06 Adoption of Roundup Ready Technology in the US (million acres) Soybean CornCotton 94% 43% 67%

24. Adoption of Next Crops Roundup Ready alfalfa? Roundup Ready sugar beets?

25. Reduce Selection Pressure Diversify herbicide use – Ideally, use more than one herbicide mode of action on all weeds every year – Rotate glyphosate with other herbicides – Use preemergence herbicides in sequential programs – Apply glyphosate in combination with other POST herbicides – Use cultivation

26. Resources Available

27. Glyphosate, Weeds, and Crops (GWC) Series http://www.glyphosateweedscrops.org/