1. Diffusion of herbicide resistance crops: Effects on adoption of conservation tillage and resistance management practices George Frisvold Department of Agricultural & Resource Economics University of Arizona Jeanne Reeves Cotton Incorporated 19 th ICABR Conference Sustainability, the Environment & Human Health Ravello, Italy June 16-19, 2015

2. Logistic Diffusion Curve

3. Simultaneous Diffusion Model

4. 3SLS Results

5. Cross-adoption elasticities

7. Adoption of Herbicide Resistant Crops in the US USDA, ERS

8. Cross-adoption elasticities Elasticity go to zero as adoption of cross-technology reaches 100%

9. US pesticide applications in kilotons 196419952005 Total Pesticides97.5235.7222.8 Total Herbicides21.9146.1144.6 Corn11.684.576.4 Cotton2.114.713.1 Soybeans1.930.938.9 Herbicide a.i / Total a.i22%62%65% USDA, NASS

10. Specific crop herbicide ai as a % of total herbicide ai 196419952005 Corn53%58%53% Cotton10% 9% Soybeans9%21%27% Three Crops71%89% USDA, NASS

11. Glyphosate Kg of active ingredient (a.i.) applied as a % of total Kg of herbicide a.i. applied CropYearPercent Corn1997 1 1999 3 200515 201035 Soybeans199511 199954 200689 Cotton1995 3 199920 200557 201062 USDA, NASS

12. Herbicides applied to corn by herbicide family and MOA % of total herbicide hectare- treatments Herbicide familyMechanism of action19962005 Phosphinic acidG (9) 219 TriazineC 1 (5) 3848 AmidesK 3 (15) 274 Benzoic / PhenoxyO (4) 155 SulfonylureaB (2) 115 PyridineF 1 (12) 06 Other herbicides89 USDA, NASS

13. Herbicides applied to cotton by herbicide family and MOA % of total herbicide hectare- treatments Herbicide familyMechanism of action19962007 Phosphinic acidG (9) 360 DinitroanilineK 1 (3) 2614 UreaC 2 (7) 206 TriazineC 1 (5) 132 Organic arsenicalZ (17) 121 BenzothiadiazoleC 3 (6) 31 Other herbicides2317 USDA, NASS

14. Herbicides applied to soybeans by herbicide family and MOA % of total herbicide hectare-treatments Herbicide familyMechanism of action19962006 Phosphinic acidG (9) 1077 DinitroanilineK 1 (3) 203 ImidazolinoneB (2) 212 SulfonylureaB (2) 9NA 2 Diphenyl etherE (14) 81 OximeA (1) 71 Aryloxyphenoxy propionic acidA (1) 7NA PhenoxyO (4) 55 AmidesK 3 (15) 42 TriazineC 1 (5) 41 BenzothiadiazoleC 3 (6) 4NA Other herbicides26

15. Planned glyphosate resistant (GR) crop plantings and residual herbicide use from a survey of 1,205 growers VariableCornSoybeansCotton 2008 GR acreage planned (%) 739692 2008 GR acreage with residual planned (%) 662866 2008 GR acreage following GR acreage planned (%) 634768 Hurley et al., 2009b

16. Fields Scouted for Weeds USDA, ARMS

17. Pre-emergence Weed Control USDA, ARMS

18. Post-emergence Weed Control USDA, ARMS

19. Cultivation for Weed Control USDA, ARMS

20. Percent of respondents who believed growers were following the practice “less” or “much less” as a result of HR crop adoption (from internet survey of agricultural professionals Practice % of respondents Combination of weed control methods>60% Crop rotation for weed control>40% Annual rotation of herbicides>50% Use of multiple herbicides>60% Tillage for weed control>80% Harrington et al., 2009

21. Room for improvement in BMP adoption Many growers practicing many Best Management Practices (BMPs) to delay resistance much of the time, but...... adoption of some of the most critical BMPs remains low

22. Most Growers Practicing Most BMPs Much of the Time

23. Growers adopting practice often or always Corn Frisvold et al., 2009

24. Note similarity in adoption across crops Corn SoybeansCotton Source: Frisvold et al., 2009

25. GR crop adoption & Resistance Management Frisvold, Hurley, & Mitchell AgBioForum, 2009, Adoption of BMPs Econometric Results from survey of >1,000 growers GR crop adoption had no effect on total count of BMPs adopted Positive effect on use of label rate Negative effect on using different MOAs

27. Glyphosate-resistant Palmer amaranth: A threat to conservation tillage Price, A. J., Balkcom, K. S., Culpepper, S. A., Kelton, J. A., Nichols, R. L., & Schomberg, H. (2011). Journal of Soil and Water Conservation, 66(4), 265-275.

28. Percentage Point Reduction in Conservation Tillage Acreage in US Soybeans from 2006 to 2012

29. Diffusion of Conservation Tillage in Soybean State-level fixed effects Diffusion speed parameter a function of % of acres that are HEL Lagged presence of glyphosate resistant weeds

30. Conservation Tillage Diffusion in Soybean

31. Summing Up Evidence of complementarity between GR crops and conservation tillage GR crops associated with reduced diversity of weed management tactics, especially w.r.t. use of MOAs Preliminary evidence that GR weeds beginning to discourage conservation tillage