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.

Common ragweed confirmed ALS inhibitor-resistant in Brown County Wisconsin

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Recently, Thomas Butts, a graduate research assistant, Vince Davis, and Dave Stoltenberg confirmed that a common ragweed population in Wisconsin is resistant to an ALS inhibitor. The full report is now available. For more information, please visit the WCWS documents page.

National Cover Crop Survey Seeks Farmers

Farmers are invited to complete this national online survey regarding their use of cover crops. This survey, conducted by the Conservation Technology Information Center (CTIC) is used to collect data on the national use of cover crops and results will be released this summer in order to increase best management practices. Farmers who complete the survey are eligible for a drawing for one of two $100 Visa gift cards.