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.

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.

Farm Financial Management Workshops for Women Farmers

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University of Extension Rusk and Taylor counties will be hosting Annie’s Project Financial Management workshops on February 25 and March 4. For more information, read Sandy Stuttgen’s news release below.

February 2015
Contact: Sandy Stuttgen, 715-748-3327, sandy.stuttgen@ces.uwex.edu,

Annie’s Project Financial Management Workshop scheduled for February and March

Medford, Wis. – University of Wisconsin-Extension Rusk and Taylor Counties are hosting a two day Annie’s Project on Farm Financial Management. The workshop will be held on Wednesday, Feb. 25 and Wednesday, March 4 from 10 a.m. to 3 p.m. at the Jump River Community Center in Jump River, Wisconsin.

This workshop series is for farm women who are interested in learning or improving their farm financial management, which is part of the fabric of farm life. The series will be inter-active between speakers and participants with in-class exercises.

Topics include:

  • Introduction to Financial Management
  • Records and Recordkeeping Systems
  • Filing Important Family Papers
  • Management Reports including the Balance Sheet and Income Statement
  • Analysis and Interpretation of Financial Statements
  • Benchmarking of Financial Position and Performance
  • Decision Making Tools including Budgets

The cost of the program is $40 which includes materials and lunch both days. Brochures and registration information are available by contacting UW-Extension Taylor County office at 715-748-3327 or http://taylor.uwex.edu/ .

Annie’s project is an opportunity for farm women to learn about farm management skills by providing resources and information to improve farming operations. Class sizes are small which allows for opportunities to network with other farm women in similar situations.

Certified Crop Advisor Training Series

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Here is another resource brought to you by University of Wisconsin Extension! Free, online certified crop advisor training videos are available now. In addition to CCA training, they are great for adding to your general knowledge about integrated pest management, soil science, and field and forage crops.

Vince Davis has created a series of weed science videos that can be accessed directly from the videos page.

Resource: Wisconsin Farm Center

Wisconsin Farm Center, another resource from the state of Wisconsin and the Department of Agriculture, Trade and Consumer Protection, releases quarterly newsletters with a wide array of topics. If you are too busy during the growing season, winter may be a great time to catch up on Farm Center newsletters. Another great way to stay up-to-date is to subscribe to their email newsletter.

The Farm Center offers a variety of services to Wisconsin farmers.

University of Wisconsin Offers Six MOOCs

University of Wisconsin-Madison is going global this winter with six new MOOCs, not a cow moo with a cough, but Massive Open Online Courses. These are free, non-credit courses taught by UW-Madison faculty. To access the courses or read more about them, go to moocs.wisc.edu. The course schedule is as follows:

  • January 26 to February 22, The Land Ethic Reclaimed: Perceptive Hunting, Aldo Leopold and Conservation
  • February 23 to March 31, Changing Weather and Climate in the Great Lakes Region
  • April 26 to May 23, Shakespeare in Community
  • June 21 to July 18, Energy and the Earth
  • September 30 to December 28, Forests and Humans: From the Midwest to Madagascar
  • November 9 to December 4, Climate Change Policy and Public Health

2015 UWEX Midwest Manure Summit

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University of Wisconsin Extension is hosting the 2015 Midwest Manure Summit on February 24 and 25 at the Radisson Hotel and Conference Center in Green Bay, Wisconsin. New to the summit for 2015 are on-farm tours and an Anaerobic Digestion pre-conference session. Additional information and registration is available at www.midwestmanure.com.

UWEX Crop Budget Analyzer

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Ken Williams, an Extension agent in Waushara county has released an updated Crop Budget Analyzer for corn, soybeans, wheat, seeding alfalfa, and established alfalfa. The Budget Analyzer is a downloadable Excel spreadsheet, which can generate handy one page print-outs.

Other UWEX and USDA resources are available to help with pricing and budgeting.