Post-emergence herbicides for corn and soybean

At this time of the year, integrated weed management programs focus on scouting and diversifying management practices including non-chemical methods and herbicide sites-of-action. For more information, please visit the United Soybean Board’s TakeAction website for field management guidelines and to learn more about herbicide sites of action. Michigan State University’s Weed Science website has detailed web pages on common weeds in annual crops with biological information and management recommendations. After each field season, the Herbicide Evaluation Program here at the university publishes efficacy data in a research report. Summary ratings for many weed species are located in “Pest Management in Wisconsin Field Crops” available as a free pdf or in print at Cooperative Extension’s Learning Store.

Post-emergence herbicides for corn and soybean

At this time of the year, integrated weed management programs focus on scouting and diversifying management practices including non-chemical methods and herbicide sites-of-action. For more information, please visit the United Soybean Board’s TakeAction website for field management guidelines and to learn more about herbicide sites of action. Michigan State University’s Weed Science website has detailed web pages on common weeds in annual crops with biological information and management recommendations. After each field season, the Herbicide Evaluation Program here at the university publishes efficacy data in a research report. Summary ratings for many weed species are located in “Pest Management in Wisconsin Field Crops” available as a free pdf or in print at Cooperative Extension’s Learning Store.

Triple threat herbicide resistant goosegrass

Researchers from the Australian Herbicide Resistance Initiative report on the first confirmed case of a weed, Indian goosegrass (Eleusine indica), resistant to three non-selective herbicides, glufosinate, glyphosate, and paraquat along with several ACCase inhibitor herbicides (Jalaludin et al., 2014). The goosegrass population was initially reported in Malaysia by a vegetable farmer and a planter from an oil palm nursery (Jalaludin et al. 2010).

In the United States, E. indica occurs in forty five of the fifty states. In Wisconsin, populations have been identified in the following counties: Columbia, Dane, Grant, Lafayette, Rock, Kenosha, and Milwaukee. The first documented case of herbicide resistant E. indica was from North Carolina in 1973 and the latest confirmation was in 2011 (Heap, 2015).

The amount of glufosinate to kill half of the tested resistant plants was equivalent to applying 40 fl oz per acre (e.g. Liberty 280 SL). The maximum rate for the season in corn is 36 fl oz per acre. The next generation of plants from the resistant population required 657 fl oz per acre of glyphosate (i.e. Roundup Powermax) to kill half of the tested population. These plants also were twice as resistant to paraquat compared to the susceptible plants. Half of the resistant population survived applications of the ACCase inhibitors- haloxyfop-P-methyl (e.g. Verdict) and fluazifop-P-butyl (e.g. Fusilade).

  1. Heap, I. 2015 The International Survey of Herbicide Resistant Weeds. Online. Available at www.weedscience.org
  2. Jalaludin, A.; Ngim, J.; Baki, BB.; Zazali, A. 2010 “Preliminary findings of potentially resistant goosegrass (Eleusine indica) to glufosinate-ammonium in Malaysia.” Weed Biology and Management 10: 256-260.
  3. Jalaludin, A.; Yu, Q.; Powles, S.B. 2014 “Multiple resistance across glufosinate, glyphosate, paraquat, and ACCase-inhibiting herbicides in an Eleusine indica population” Weed Research 55: 82-89.

For more information about herbicide resistance management, please visit our documents page, video page and/or the TakeAction on Weeds website.

Glyphosate resistance confirmed in two Wisconsin common waterhemp populations

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Recently, Thomas Butts, a graduate research assistant, and Vince Davis confirmed two herbicide-resistant common waterhemp populations in Wisconsin. The full report is now available. For more information, please visit the WCWS documents page.

Palmer amaranth confirmed glyphosate-resistant in Dane County, Wisconsin

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Thomas Butts, a graduate research assistant, and Vince Davis report a new confirmation of a glyphosate-resistant weed in Wisconsin. Their full report is available here. For more information, please visit the WCWS documents page.

Palmer amaranth confirmed glyphosate-resistant in Dane County, Wisconsin

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Thomas Butts, a graduate research assistant, and Vince Davis report a new confirmation of a glyphosate-resistant weed in Wisconsin. Their full report is available here. For more information, please visit the WCWS documents page.

Start the New Year with Herbicide Resistance Management

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Here is another WCWS video discussing strategies to manage herbicide resistance. Get great weed control and save a bag of soybean seed by using a residual herbicide. Check out more WCWS videos at http://wcws.cals.wisc.edu/videos.

Event- 2015 Wisconsin Crop Management Conference

The 2015 Wisconsin Crop Management conference will be held at the Alliant Energy Center in Madison, Wisconsin from January 13 until January 15. To save on advance registration, make sure to submit your form and payment by December 19, 2014.

To access the conference programming, go here for a complete list of events and the registration form. Also, online registration is available here.

Vince Davis, Thomas Butts, and Dan Smith will be presenting at this year’s conference. During the Weed Management section on Wednesday January 14, Vince will be talking about “Efficacy of “new” herbicides and program approaches for resistance management.” Tommy will be discussing his latest research results, “Herbicide-resistant pigweeds (Amaranthus spp.) are in Wisconsin, how serious is it?” Dan will be presenting his research on “Cover crop establishment following commonly applied corn and soybean herbicides in Wisconsin.”

More Winter Reading, the 2014 WCWS Research Report

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Yep, it is that time of year. Winter is setting in and the 2014 WCWS Research Report is here to chase away the winter blues. Print copies will be distributed at the Pest Management Update meetings and at the Wisconsin Crop Management conference. Check out our Documents page again in December for an updated report with yield data.