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The mission of this program is to evaluate weed management practices to help Wisconsin growers sustainably control weeds and maximize the production of corn, soybean, small grains, and sweet corn crops. Through integration of applied field research and extension activities, we strive to deliver thorough, unbiased results to Wisconsin crop producers and improve upon the body of scientific weed science literature.

To read the complete blog, please visit the Out of Control page.

Why Use Cover Crops and Green Manures In Your Home Vegetable Garden?

Using cover crops and green manures can be beneficial to the soil of your vegetable garden. Cover crops can help return nutrients to the soil, increase the amount of organic matter in the soil, and prevent erosion. These things help to build a better soil structure which leads to better water infiltration and allows the soil to hold nutrients and water more efficiently. Green manures are used to increase organic matter and add nutrients to the soil. Green manures in the pea family can increase the levels of nitrogen in the soil by using a bacteria in their roots to take nitrogen from the air and turn it into nitrogen that plants can use.

You can find information on which cover crops will be most beneficial to your garden and best management practices on the Wisconsin Horticulture website. This article was created by Doug Higgins, Kristin Krokowski, and Erin Silva.

Information regarding the best cover crop rotation practices for your garden can be found here.

 

Herbicide Injury Diagnosis for Corn Seedlings at Emergence

Depending upon the herbicide, injury can occur after a pre-emergence application when corn is germinating in cool, wet soils. This year, if corn was planted in mid-April then you may observe some injury. However, it is important to remember that other environmental factors can mimic herbicide injury symptoms such as corn emerging in crusted or compacted soil. For this spring, WCWS has a re-designed online diagnostic tool, available at http://wcws.cals.wisc.edu/herbicide-injury-diagnostic-tool or from the main page, go to ‘Resources’ and then to ‘Tools’. The diagnostic tool asks three basic questions 1) When do injury symptoms appear? 2) Are both broadleaves and grasses affected or just one group? and 3) What are the symptoms and where do they occur? The original web-based tool was developed by Tim Trower and Chris Boerboom to accompany a handy two-page guide. The following changes were made to the new version:

  1. Each page shows your previous answers.
  2. A ‘Start over’ button is located at the bottom of each page.
  3. For each herbicide mode-of-action, an herbicide chart from the TakeAction Herbicide Classification poster or on the WCWS website under ‘Resources’, ‘Documents’(Fig. 1).
  4. Simplified guides to symptoms that mimic herbicide injury during and after emergence are included on each mode-of-action page (Fig. 2).
  5. Photo galleries for both corn and soybean injury symptoms are located on the same page (Fig. 3).

Figure 1. Herbicide site-of-action groups, chemical  families, active ingredients, and product examples for the seedling shoot growth inhibitor mode-of-action.  Specific sections of the larger TakeAction chart are on each mode-of-action page.

Figure 1. Herbicide site-of-action groups, chemical families, active ingredients, and product examples for the seedling shoot growth inhibitor mode-of-action. Specific sections of the larger TakeAction chart are on each mode-of-action page.


Figure 2. Mimics of herbicide injury to corn during or at emergence.

Figure 2. Mimics of herbicide injury to corn during or at emergence.


Figure 3. Example of a photo gallery for corn and soybean herbicide injury symptoms.

Figure 3. Example of a photo gallery for corn and soybean herbicide injury symptoms.

For pre-emergence applications in corn, the seedling shoot growth inhibitors, particularly the chloroacetamides, may injure seedlings when soils are cool and wet. Injury will not always be apparent aboveground. For example, corn plants with seedling root growth inhibitor damage will display clubbed root tips and grasses will be more affected than broadleaves. To get an idea of injury risk, check out the herbicide tables in “Pest Management in Wisconsin Field Crops” available in pdf and print formats at Cooperative Extension’s Learning Store.

When Does a Weed Become “Super”?

The term “superweed” has come to mean any weed that has become difficult to manage even if there has only been one or two management techniques employed. However, according to the Weed Science Society of America, this isn’t what a true superweed is. Just because a weed has developed resistance to one management technique (such as how dandelions begin to produce seed differently in a regularly mowed lawn), does not make it “super”. A true super weed has the ability to develop resistance to all kinds of management techniques, including multiple herbicides and mechanical, biological, or cultural management techniques. This new definition of superweed is hoped to clear up any confusion and encourage proper weed management techniques. More information about what a superweed really is can be found here.

Scout your fields for weed seedlings this spring

Figure 1. A) Common lambsquarters, Chenopodium album; a soil sampler, one inch diameter, is in the foreground B) Horseweed (marestail), Conyza canadensis; C) Giant ragweed, Ambrosia trifida, with seed capsule attached; D) Giant ragweed seedlings.

Figure 1. A) Common lambsquarters; a soil sampler, one inch diameter, is in the foreground B) Horseweed (marestail); C) Giant ragweed, with seed capsule attached; D) Giant ragweed seedlings.

The fields may look cold, wet, and dormant this week but weeds were germinating in some fields in Janesville and Arlington last week. On April 17 at Janesville, common lambsquarters, giant ragweed, and horseweed were emerging (Fig. 1A-D). At Arlington in a plowed area, velvetleaf was emerging (Fig. 2). If you are leasing new land this year or want to get a head start on weed management, then scouting for weeds at the seedling stage before tillage can be a good way to assess density, the number of weeds in a given area, and for which weed species will likely be an issue around planting time. The Weedometer, developed by University of Wisconsin, can predict when weed species will likely be emerging for your location at http://weedecology.wisc.edu/weedometer/ . A guide to identifying the “Common Weed Seedlings of the North Central States” is available in pdf and print formats at Cooperative Extension’s Learning Store, or on the WCWS Weed info page.

Figure 2. Velvetleaf seedling.

Figure 2. Velvetleaf, Abutilon theophrasti, seedling.

UW Cooperative Extension Cover Crop Workgroup Website

What are the economic costs of cover crops? What are the environmental and economic benefits? How do the nutrients from cover crops cycle through the soil? What is The New York Times saying about cover crops? All of this information and much more can be found on the UW Cooperative Extension Cover Crop Workgroup website, where UWEX personnel across Extension programs and disciplines provide resources regarding cover crops which will be frequently updated.

Yahara Watershed Videos

Wisconsin’s Yahara Watershed encompasses lakes Mendota, Monona, Waubesa, Wingra, and Kegonsa, and also includes the Lakeshore Nature Preserve.The UW-Madison Water Sustainability and Climate project created the Water Walk video series to provide a virtual tour of this beautiful area as well as to show how human activities impact the quality of water in the watershed.