Diversify your Weed Management Toolbox

The Weed Science Society of America recently held an Herbicide Resistance Summit that brought together leading weed scientists from around the world to discuss the future of herbicide resistance at the National Academy of Sciences in Washington D.C. All of the presentations are on YouTube.

If you have 1 minute or 30 minutes, take the time to hear what the Director of the Australian Herbicide Resistance Initiative, Stephen Powles, says about herbicide resistance in the United States.

Highlights:

Diversify Weed Management

The Transgenic Treadmill

Avoiding the Herbicide Resistance Train Wreck in the United States

Harvest Weed Seed Control

Full Presentation

On the Bookshelf: 2015 Pest Management in Wisconsin Field Crops

Don’t miss this year’s “Pest Management in Wisconsin Field Crops” from University of Wisconsin Extension. This is a comprehensive guide to insect, weed, and plant disease management in corn, soybean, forage, and stored grain crops.

To obtain a print copy of the guide, go here. For a free electronic copy in pdf format, go here for the download. For mobile access, go to University of Wisconsin Extension’s Pest Management Mobile.

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.

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.

Hurry! Register for Pest Management Update Meetings

Hopefully, you will have finished or nearing the end of harvest by mid-November and will be ready to attend Extension’s Pest Management Update series. County Extension agents across Wisconsin will be hosting Pest Management Update Meetings during the second and third weeks in November. The purpose of each meeting is to review the past growing season and provide updates on research that can be applied to your farm. The speakers are Extension State Specialists including:

  • Bryan Jensen, Entomologist
  • Damon Smith, Field Crops Pathologist
  • Dan Heider, IPM Specialist
  • Mark Renz, Weed Scientist for Perennial Cropping Systems
  • Vince Davis, Weed Scientist for Annual Cropping Systems

Please register one week prior to the event. For a complete schedule of meetings including county agent contact information, please go here. Registration includes lunch, an information packet, and a copy of the 2015 Pest Management in Wisconsin Field Crops book. Four hours of CEU pest management credits will be available at each location. The registration fee is $40.

Winners Announced from the Biggest Weed Contest

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The Department of Agronomy’s Mark Renz announces this year’s winners of the Biggest Weed Contest at the Farm Technology Days, August 12-14, 2014.

2014 Contest Winner

This giant ragweed, submitted by Ken McGwin of Montello, was the Day 1 winner of the Biggest Weed contest at Wisconsin Farm Technology Days. Measuring 12’6” x 4’, its overall size wasn’t big enough though to beat the grand champion – another giant ragweed measuring over 10 feet tall and seven feet wide.

Here is Mark’s press release:

Contact: Mark Renz, UW-Extension weed specialist, 608-263-7437, mrenz@wisc.edu

Biggest Weed contest winners announced

Madison, Wis. – Despite the cool summer, plenty of weeds were entered in the ‘Biggest Weed’ contest sponsored by University of Wisconsin-Extension/Madison Weed Experts at the recent Wisconsin Farm Technology Days. Of the many samples brought in for identification, eight participants submitted nine weeds they felt deserved the title of Biggest Weed.

“While none of the samples topped the 13 foot mark like last year, several were quite wide, making up for the lack of height,” said Mark Renz, University of Wisconsin-Extension/Madison weed specialist. “Of the nine samples submitted, four were annuals, four biennials, and only one perennial plant – common milkweed.”

Typically the biennial and perennial plants take the prize, but this year a giant ragweed was the grand champion. Wayne Greeler from Neillsville, Wisconsin brought in this specimen that was over 10 feet tall and seven feet wide. The overall size of the plant is determined by multiplying the weed’s height by the maximum width when held in its normal growth form.

Renz said, “It is uncommon for a giant ragweed to get this wide but the extra girth allowed it to take the grand prize.”

Tuesday’s winner was another giant ragweed submitted by Ken McGwin from Montello. It was much taller than the grand champion, more than 12 feet, but only four feet wide. Wednesday’s winner Mary Jane Fry from Pittsville did bring in a massive bull thistle, but its dimensions couldn’t match the winners from Tuesday or Thursday.

“All submissions were found next to a barn, shed, fence, or tree,” Renz noted, “So apparently having a structure nearby helps. Remember this tip when we hold the event next year at Wisconsin Farm Technology Days in Dane County.”

All daily winners will receive a weed identification book, as thanks for hauling these winning specimens to Wisconsin Farm Technology Days. Anyone who has tried to bring in one of these plants can attest that it is no easy task.

For more information about identifying and controlling weeds in your field or yard, contact your local county Extension agent or visit the University of Wisconsin Weed Science website at http://fyi.uwex.edu/weedsci

 

To-Do List: Fall Dandelion Management

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It’s time to start planning ahead for fall dandelion management. The Weed Science website at the University of Wisconsin Extension has a thorough description of the dandelion’s life cycle and some suggestions for control. A group of researchers at the University of Wisconsin evaluated fall and spring herbicide applications for control of dandelion in 2011. Their key findings were:

  1. Herbicide applications in the fall were most effective for early-season dandelion control compared to applications at normal corn planting in the spring.
  2. Applications during the spring were ideal for late-season control when soybean planting occurs.

For specific information on herbicides, please see their slide presentation.

The flowering stage of dandelion is easily identified by most. However, identifying the seedling stage is helpful because management is best before dandelions enter the adult stage. The following plant characteristics will help with identifying seedling dandelions:

  • Seed leaves (cotyledons) are oval or spoon-shaped
  • First true leaf is ovular and 0.4 inches (1 cm) long. Leaf margins have a few very small teeth that point back toward the base of the leaf. The midvein is prominent on the underside of the leaf.
  • Later leaves are more elongated and will have the toothed margins and rosette arrangement typical of the mature plant.

Managing dandelions can either be done through the use of herbicide or physical removal in either the spring or fall. However, dandelions are more susceptible to herbicides applied in the fall. If physical removal is the management mode of choice, it must be done in the spring as well as the fall.

Management options for corn and soybean are listed below.

Corn

Chemical control options:

  • Fall application of 2,4-D or dicamba at 1 pint per acre applied alone or as a tank mix prior to the first killing frost. Another option is glyphosate but for optimal activity applications need to be made when the air temperature is above 50 degrees F and the plant is still actively growing.
  • Spring applications of 2,4-D ester at 1 pint per acre prior to corn emergence or a tank-mix of 2,4-D with glyphosate will provide some dandelion control. Also, post-emergence applications of growth regulator herbicides typically provide acceptable control.

Mechanical control options:

  • Moldboard or chisel plowing will weaken the plant by disturbing the taproot and may make chemical applications more effective.

Soybean

Chemical control options:

  • 2,4-D ester may be applied prior to soybean planting if a seven-day interval is observed between application and planting.
  • There are no good post-emergence options for dandelion control in soybeans.
  • If possible, control heavy infestations of dandelions in the fall if the field is to be planted to no-till soybeans.

References:

  1. http://www.extension.psu.edu/pests/weeds/weed-id/common-dandelion, site accessed July 27, 2014.
  2. http://www.umanitoba.ca/outreach/naturalagriculture/articles/dandelion.html, site accessed July 27, 2014.
  3. http://fyi.uwex.edu/weedsci/2002/11/12/dandelion/, site accessed July 27, 2014.

Authors:

Madeline Fischer and Liz Bosak

Madeline Fischer is an undergraduate research assistant working for WCWS at the Arlington Agricultural Research Station. In Fall 2014, Madeline will be a sophmore pursuing a degree in Life Science Communcations and Environmental Studies.

To-Do List: Late-Season Scouting

A critical component of herbicide resistance management and integrated pest management is scouting for pests. In this case, it is time to start thinking about scouting for late-season weed escapes. Late-season weed scouting will help to focus your weed management plans for next year- what worked, did not work, and which weed species may be a problem during the next growing season. If you suspect that you have found an herbicide-resistant weed, please contact your local county Extension agent or Vince Davis at vmdavis@wisc.edu

To learn more about late-season weed scouting in soybean, please watch Vince’s videos:

http://www.youtube.com/watch?feature=player_embedded&v=eD2QBM3xxH8
http://www.youtube.com/watch?feature=player_embedded&v=CkDqduaUjyY

For more videos, please visit our video page, http://wcws.cals.wisc.edu/videos/