Wisconsin Cropping Systems Weed Science Program

Weed Science Knowledge to Academics and Practitioners

UW-Madison | UW-Extension

On October 31, 2018 the United States Environmental Protection Agency announced their decision to extend the registration of the dicamba products Engenia, Fexapan, and Xtendimax for use in dicamba-tolerant crops (Xtend technology) through December 20, 2020; however, additional label changes were made. In this post, I (try to) address the new 57-foot omnidirectional buffer requirement to protect federally listed threatened and endangered species and critical habitat in specific US counties.


20 unique cases (weed species by herbicide site of action) of herbicide resistance have been confirmed in Wisconsin, including 13 weed species with evolved resistance to one or more herbicide sites of action. Herein we share the current state of documented herbicide resistance cases in Wisconsin crop production.


Looking for some research-based information to assist with PRE-emergence soybean herbicide selection for waterhemp control? Check the results of the “2018 UW Waterhemp Challenge: Comparison of Soil Residual Soybean Herbicides Study”


Check the “Herbicide Site of Action Key for Crop Injury Symptoms” developed to help corn and soybean farmers, agronomists, Ag educators and crop scouts identify potential herbicide injury symptoms on crops.


We invite Wisconsin farmers and agronomists to collect waterhemp seeds this fall from their row crop production fields and submit them to UW-Madison for herbicide resistance screenings.



Coming soon!


Technical Bulletins

Research reports will be shared here after our first field season.




20. Stepanovic, S.V., C. Burr, J.A. Peterson, D. Santra, D. Rudnick, T. Adesemoye, C.F. Creech, and R. Werle. 2018. Field peas response to seeding rate, depth and inoculant in west-central Nebraska. Agronomy Journal. 2018. In Press.

19. Werle, R., and J. Miller. 2018. Survey of Nebraska soybean producers: current and future status of weed management. Journal of Extension. 56(2).

18. Werle, R., C. Burr, and H. Blanco-Canqui. 2018. Cereal rye cover crop suppresses winter annual weeds. Canadian Journal of Plant Science. 98:498-500.

17. Vieira, B.C., S.L. Samuelson, G.S. Alves, T.A. Gaines, R. Werle, and G.R. Kruger. 2018. Distribution of glyphosate-resistant Amaranthus spp. in Nebraska. Pest Management Science. Wiley Online Library. DOI 10.1002/ps.4781

16. Rudnick, D.R., T. Lo, J. Singh, R. Werle, F. Munoz-Arriola, T. Shaver, C.A. Burr, T.J. Dorr. 2018. Reply to comments on “Performance assessment of factory and field calibrations for electromagnetic sensors in a loam soil”. Agricultural Water Management. 203:272-276.

15. Singh, J., T. Lo, D.R. Rudnick, T.J. Dorr, C.A. Burr, R. Werle, T.M. Shaver, F. Munoz-Arriola. 2018. Performance assessment of factory and field calibrations for electromagnetic sensors in a loam soil. Agricultural Water Management. 196:87-98.


14. Barnes, E., R. Werle, L.D. Sandell, J.L. Lindquist, S.Z. Knezevic, P.H. Sikkema, and A. Jhala. 2017. Influence of tillage on common ragweed (Ambrosia artemisiifolia) emergence pattern in Nebraska. Weed Technology. 31:623-631.

13. Werle, R., K. Begcy, M. K. Yerka, I. Dweikat, A. J. Jhala, J. P. Mower, and J. L. Lindquist. 2017. Independent evolution of acetolactate synthase-inhibiting herbicide resistance in weedy Sorghum populations across common geographic regions. Weed Science. 65:164-176.

12. Werle, R., B. Tenhumberg, and J. L. Lindquist. 2017. Modeling the evolution of shattercane resistance to ALS-inhibiting herbicides in an ALS-tolerant sorghum cropping system. Ecological Modeling. 343:131-141.


11. Saini, S., R. Werle, L.D. Sandell, and A. Jhala. 2016. Spring-tillage has no effect on the emergence pattern of glyphosate-resistant giant ragweed (Ambrosia trifida L.) in Nebraska. Canadian Journal of Plant Science. 96: 726-729.

10. Werle, R., A. Jhala, M.K. Yerka, J.A. Dille, and J.L. Lindquist. 2016. Distribution of herbicide-resistant shattercane and johnsongrass populations in sorghum production areas of Nebraska and northern Kansas. Agronomy Journal. 108:321-328. Invited Submission.


9. Werle, R., L.J. Giesler, M.L. Bernards, and J.L. Lindquist. 2015. Likelihood of soybean cyst nematode (Heterodera glycines) reproduction on henbit (Lamium amplexicaule) roots in Nebraska. Weed Technology. 29:35-41.

8. Werle, R., L.D. Sandell, D.D. Buhler, R.G. Hartzler, and J.L. Lindquist. 2014. Predicting emergence of twenty three summer annual weed species. Weed Science. 62:267-279.


7. Werle, R., M.L. Bernards, T.J. Arkebauer, and J.L. Lindquist. 2014. Environmental triggers of winter annual weed emergence in the midwestern United States. Weed Science. 62:83-96.

6. Werle, R., L.L. Perez, L.D. Sandell, and J.L. Lindquist. 2014. Corn (Zea mays) emergence and early growth as influenced by tansymustard (Descurainia pinnata) residue. Crop Management. doi:10.2134/CM-2013-0088-RS.

5. Werle, R., J.J. Schmidt, J. Laborde, A. Tran, C. Creech, and J.L. Lindquist. 2014. Shattercane X ALS-resistant sorghum F1 hybrid and shattercane interference in ALS-resistant sorghum. Journal of Agricultural Science. 6:159-165.


4. Werle, R., M.L. Bernards, L.J. Giesler, and J.L. Lindquist. 2013. Influence of two herbicides on soybean cyst nematode (Heterodera glycines) reproduction on henbit (Lamium amplexicaule) roots. Weed Technology. 27:41-46. Outstanding paper in Weed Technology.


3. Han, C., C. Borman, D. Osantowski, J. Wagnitz, K. Koehler-Cole, K. Korus, E. Sonderegger, R. Werle, T. Wood, and J. L. Lindquist. 2012. Productivity of field pea (Pisum sativum L.) and spring oat (Avena sativa L.) grown as sole and intercrops under different nitrogen levels. Journal of Agricultural Science. 4:136-143.


2. Rosolem, C.A., R. Werle, R.A. Garcia. 2010. Nitrogen washing from C3 and C4 cover grasses residues by rain. Revista Brasileira de Ciência do Solo. 34:1899-1905.


1. Werle, R., R.A. Garcia, C.A. Rosolem. 2008. Potassium leaching as affected by soil texture and potassium availability. Revista Brasileira de Ciência do Solo. 32:2297-2305 (In Portuguese with English abstract).


Those who get the work done!

Ryan DeWerff (Research Specialist)

Ryan DeWerff

Maxwel Coura Oliveira (Postdoctoral Research Associate)

Maxwel Oliveira

Sarah Striiegel (MS Graduate Student)

Sarah Striegel

Nikola Arsenijevic (MS Graduate Student)

Nikola Arsenijevic

Victor Ribeiro (Visiting MS Graduate Student)

Victor Ribeiro

Former Lab Members

No one has left (thankfully) or graduated from our program yet!