Soybean Weeds

C.O.R.N. Newsletter Articles

  1. Marestail (Horseweed)
    Author(s): Mark Loux

    A uniform wheat crop can provide effective suppression of marestail, especially when combined with some in-crop herbicides.  It is nonetheless typical for marestail plants to be evident after the wheat is harvested, and these should be controlled prior to double crop soybean emergence.  There can be a couple types of marestail plants to deal with in this situation:  1) small ones that were lurking near the base of the wheat plants, which are largely not disturbed by the combine; and 2) larger ones that may have been present in areas of thin wheat stand, which get cut off by the combine and

    Issue: 2018-21
  2. Author(s): Mark Loux

    Dicamba can have a good fit in spring preplant burndown programs, especially for control of overwintered marestail in fields not treated the previous fall. We typically recommend a preplant burndown that includes at least two herbicides with substantial activity on marestail in this situation, such as Sharpen + 2,4-D or Gramoxone + 2,4-D + metribuzin. Dicamba is the most effective burndown herbicide on glyphosate-resistant marestail in the spring though, and in our research has usually killed or at least stopped emerged marestail in their tracks without help from other herbicides.

    Issue: 2018-05
  3. Author(s): Mark Loux

    There is obviously a lot going on with the dicamba issue, resulting in uncertainty as to where exactly we are headed with regard to future labels, restrictions, and stewardship.  However, we are fairly confident that the label for early-season use of dicamba in preplant/premeergence burndown programs will be preserved into next year at least  (“dicamba” in this article refers to the three dicamba products approved for use in Xtend soybeans – Engenia, XtendiMax and FeXapan).  Dicamba is more effective than 2,4-D on marestail in the spring, and has a good fit in burndown programs to help with

    Issue: 2017-31
  4. Palmer amaranth seedhead
    Author(s): Mark Loux

    Palmer amaranth has shown up in a few more places in Ohio this summer at a range of infestation levels, and waterhemp has also become more prevalent. Newly discovered Palmer infestations in some fields were too high to be remediated by walking fields and removing plants, although there is still some potential to mow down weeds and soybeans to prevent seed production and even bigger problems next year. Infestation level in a few other fields was low enough to allow removal of Palmer amaranth plants by a crew of concerned people.

    Issue: 2017-27
  5. Author(s): Mark Loux

    As a result of the warm winter and early spring, weed growth in no-till fields is ahead of schedule.  Fields not treated with burndown herbicides last fall or during the earlier drier period this spring can have some large weeds at this point.  Many fields need time to dry out following the most recent rains before they will tolerate traffic, which will allow weeds to get even larger and more challenging to kill.  Large marestail can be especially problematic due to the combination of glyphosate and ALS resistance in most populations.  Cool weather can reduce the activity of the herbicides

    Issue: 2017-12

Publications

  1. 12/2016

    Ohio, Indiana and Illinois Weed Control Guide, Bulletin 789. Publication gives detailed guidance on weed control selections. Numerous tables by crop and application help producers select the best product option for their weed control situation. 

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