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:
- Herbicide applications in the fall were most effective for early-season dandelion control compared to applications at normal corn planting in the spring.
- 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.
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.
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.
- http://www.extension.psu.edu/pests/weeds/weed-id/common-dandelion, site accessed July 27, 2014.
- http://www.umanitoba.ca/outreach/naturalagriculture/articles/dandelion.html, site accessed July 27, 2014.
- http://fyi.uwex.edu/weedsci/2002/11/12/dandelion/, site accessed July 27, 2014.
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.
Please check out our new factsheet Herbicide Rotation Restrictions in Forage and Cover Cropping Systems.
Here is a short excerpt:
Designing effective herbicide programs while following pesticide label restrictions can be challenging in any cropping system. With rotations that include forage and cover crops, the challenge can be increased-especially when a planned cover crop might be needed as supplemental or emergency forage. In this case, the best approach is to be aware of crop rotation restrictions ahead of time and plan the most effective solutiuon for all possible scenarios.
For more information on this topic, please see another WCWS article- Is it legal to use a cover crop as a forage crop? Maybe not.
In Wisconsin, it is not easy to get your cover crop seeded after corn silage, corn grain, or soybean harvests. From Penn State, researchers have been working on equipment modifications to seed a cover crop while side-dressing a corn crop with nitrogen and applying a POST herbicide.
Under Cover Farmers is a video featuring farmers discussing how they use cover crops and specifically rolling-crimping for termination in a conventional system. The video is 28 minutes in length and was produced by the USDA-NRCS.
It’s worth taking a long coffee break and hearing what these farmers have to say.
Don’t miss this year’s Pest Management in Wisconsin Field Crops guide from University of Wisconsin Extension.
New updates to the weed managment section include:
- Another glyphosate-resistant weed from Jefferson County has been confirmed.
- Several active ingredient name changes.
- New herbicides have been added to the corn and soybean chapters.
Farmers in Illinois are paying attention to the growing Buy Local and farm-to-school campaigns sweeping through their communities and finding ways to diversify their farm income. The New York Times article “The Seeds of a New Generation” features several Illinois farmers who have alotted some of their acreage to new fruit orchards and vegetable production. To read the article, go here.
The introduction and continued use of genetically modified crops has sparked furious debates. The scientific journal Nature, a preeminent publication, has a series of articles with a relatively balanced evaluation of transgenic crops including a very good article evaluating the myths and truths swirling around popular case studies.
Are you looking for ways to expand your cover crop* seeding window? Here in Wisconsin, the cover crop species options after harvest are rather limited. For instance, this year in Columbia county, planting a cover crop into a field planted in corn for grain on June 1 with a projected harvest date of October 15 results in only one choice with no freeze risk to establishment according to the Midwest Cover Crops Council selector tool- cereal (winter) rye.
Seeding a cover crop into an existing corn crop before harvest is a strategy to extend the number of cover crop species that will establish good stands before frost. Farmers in Indiana have been using modified high-clearance sprayers to seed cover crops before the main crop harvest. Want to learn more? Dan Perkins, an Indiana Extension agent, provides a detailed discussion in his video.
*What is a cover crop? It is a crop planted between main crops that is NOT intended for harvest. For a discussion of the benefits and drawbacks of different cover crop species, consult the Midwest Cover Crops Council website or “Managing Cover Crops Profitably”, for a free pdf copy go here. Also, the Midwest Cover Crops Council in partnership with the Purdue Crop Diagnostic Training and Research Center have produced a handy pocket guide to cover crops. To purchase, visit this site.
Wisconsin’s Department of Agriculture, Trade, and Consumer Protection produces The Wisconsin Pest Bulletin at weekly or semi-monthly intervals. For email notifications, go here. The bulletins are archived and available as printable pdf documents.
What information can you find in the bulletin?
- Degree day accumulations for towns located throughout Wisconsin.
- A pest forecast with scouting guidelines for different pests.
- Scouting reports for several cropping systems arranged by the following categories: forages and grains, corn, soybeans, fruit, nursery and forest, and vegetables.